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Among the influential figures that shaped the scientific revolution during the Renaissance, the figure of Galileo Galilei stands out (Rubio, n.d.). This Italian mathematician, physicist, and scientist made a significant contribution to science and changed the paradigm regarding the position of the Earth in the Universe (Rubio, n.d.). As expressed by Cajal (n.d.), due to all the aforementioned and his tireless work in the development of the scientific revolution and the scientific method, he is considered the father of modern science. Biography Galileo Galilei was born on February 15, 1564, in Tuscany, more precisely in the city of Pisa (Cajal, n.d.). His parents, Vincenzo Galilei, a mathematician and musician from Florence, and Giulia Ammannati di Pescia, from a family of artisans, took charge of his education until he turned ten (Cajal, n.d.; Rubio, n.d.). However, the family had to move to Florence, and unable to care for Galileo, they delegated his education to a neighbor named Jacobo Borhini, a man of deep religious faith (Rubio, n.d.; Cajal, n.d.). According to Cajal (n.d.), it was precisely Borhini who arranged for Galileo's entry into the convent of Santa Maria Vallombrosa in Florence. The news was not well-received by Galileo's father, who was not particularly religious (Rubio, n.d.). Therefore, he decided to withdraw his son from the monastery, and in 1581, enrolled him in the University of Pisa to study medicine (Rubio, n.d.). However, four years later, he left the university without a degree but with a solid understanding of Aristotle (Fernandez & Tamaro, 2004). This experience allowed him to discover his true vocation: physics (Farias, 2021). At the age of twenty, he began conducting experiments in mechanics, catching the attention of several professors (Rubio, n.d.). His self-taught knowledge in mathematics was so extensive that at the age of twenty-five, he secured a position as a mathematics instructor at the University of Pisa. According to Rubio (n.d.), in 1592, he moved to Padua and began working as a professor at the university, teaching subjects such as astronomy, mechanics, and geometry. During the eighteen years he spent in Padua, until his departure in 1610, he made most of his discoveries (Rubio, n.d.). Despite the omnipresent threat of the Spanish Inquisition in Europe, Padua was a metropolis distant from religious repression (Cajal, n.d.; Rubio, n.d.). This allowed him to conduct his experiments in complete tranquility, without feeling threatened by this oppressive institution (Cajal, n.d.; Rubio, n.d.). During his time in Padua, he formulated the law describing the accelerated motion of objects, observed the stars, verified the operation of the water pump, built the precursor to the thermometer, and studied magnetism (Rubio, n.d.). In fact, according to Rubio (n.d.), a milestone in his professional career occurred there in 1609 when he perfected the telescope and could observe the night sky in a way that no one had seen before, acquiring the knowledge that allowed him to challenge the geocentric theory. Through his observations, he concluded that the Sun, and not the Earth, is the center of the galaxy (Rubio, n.d.). This conclusion was based on the scientific method, not beliefs or assumptions. Simultaneously, by recognizing that the Earth was not the center of the Universe, he also acknowledged that the planet was in motion. With this, he confirmed the premise formulated years earlier by Nicolaus Copernicus, who claimed that the Earth was not the center of everything. Additionally, according to Rubio (n.d.), his telescope observations helped him demonstrate that celestial bodies did not revolve around the Earth, but rather planets orbited the Sun. In 1611, he embarked on a journey to Rome with the purpose of presenting his discoveries (Rubio, n.d.). His opposition to the model that had been accepted in Renaissance society until then attracted the attention of several researchers, as well as the disapproval of most ecclesiastical authorities. Asserting that the Earth was not the center of everything was an attack on one of the fundamental pillars of the Church and Christian religion. The censorship was immediate, and in 1616, the Spanish Inquisition prohibited him from defending, disseminating, teaching, and promoting the heliocentric theory. Despite the repression against his science, he continued researching and developing his studies, as well as publishing works. To circumvent censorship, instead of "defending" heliocentrism, he presented this idea as a hypothesis, which technically did not defend it but described it. According to Rubio (n.d.), this was a clever and subtle nuance that allowed him to continue publishing for some time. Over the decades, perhaps a bit tired of presenting a scientific fact as a mere hypothesis, he openly defended the heliocentric theory in 1632 in a work titled "Dialogues on the Two Chief World Systems" (Rubio, n.d.). This time, the Spanish Inquisition quickly realized and began investigating the situation as heresy. One year later, at the age of sixty-nine, he was accused in Rome of violating the 1616 censorship, treating it as an infringement and threatening him with torture. He was ultimately forced to retract the heliocentric theory and his findings. After rejecting his ideas, his sentence was reduced to house arrest, which, though unjust, was preferable to being tortured by the more sophisticated inquisitorial means. According to Rubio (n.d.), legend has it that upon leaving the court, he muttered "Eppur si muove," alluding to the fact that the Earth would continue moving as he had observed. House arrest lasted from 1633 to 1638, during which he became blind (Rubio, n.d.). Realizing that Galileo had become blind, the Spanish Inquisition showed some Christian mercy and allowed him to move to a residence near the ocean. There, he continued working with several of his students, including Evangelista Torricelli and Vincenzo Viviani (Cajal, n.d.). Finally, he died on January 8, 1642, at the age of seventy-seven (Rubio, n.d.). According to Rubio (n.d.), he died rejected by his followers, who did not forgive him for yielding to inquisitorial pressure, and was seen as a heretic by the Holy Church, an institution that acknowledged its mistake in condemning him in 1992. Scientific Method Galileo Galilei is recognized for introducing an innovative approach to research, supported by the scientific method (Cajal, n.d.). The development and implementation of the scientific method were crucial for the advancement of true science (Farias, 2021). For Galilei, hypotheses were essential and would be accepted or rejected based on empirical observations. However, according to Farias (2021), what should be avoided was adopting Church truths and absolutizing them without subjecting them to the scientific method. Heliocentric Theory Galileo Galilei is acknowledged for his heliocentric theory, which led him to face the Inquisition's tribunals (Rubio, n.d.). This contribution is considered a crucial moment in the separation between Church and science. Through his observations, he strengthened the Copernican theory, asserting that the Earth revolves around the Sun and not the other way around (Rubio, n.d.). This heliocentric theory was one of the most significant scientific revolutions in the history of science, changing the previous paradigm and making people realize they were not the center of the cosmos but part of a celestial body, among others, revolving around a star. However, it's important to note that he was mistaken in thinking the Sun was the center of the Galaxy (Rubio, n.d.). Indeed, according to Rubio (n.d.), the Sun is the heart of the Solar System, but today it's known that the Sun orbits around larger celestial objects, and its position in the Milky Way is rather peripheral. Telescope Improvement Galileo Galilei is often incorrectly credited with inventing the telescope (Redd, 2017). He did not invent the telescope from scratch since similar devices with lenses that magnified objects already existed (Rubio, n.d.). However, according to Rubio (n.d.), it was Galileo Galilei's insight that made it possible to optimize these devices, giving rise to the first telescope as known today, an instrument capable of magnifying celestial bodies up to 30 times. Observations of the Sky Thanks to the development of his telescope, Galileo Galilei is recognized for having observed the sky in a way that no one had achieved before (Rubio, n.d.). He pioneered the observation of lunar craters, sunspots, the four largest satellites of Jupiter, the phases of Venus, and other astronomical phenomena and bodies (Rubio, n.d.). Finally, in line with Cajal (n.d.), the telescope revealed that the cosmos contained a much greater number of stars than those visible to the naked eye. Laws of Motion Galileo Galilei is acknowledged as an inspiration and precursor to the laws of motion, later formulated by the English physicist and mathematician Isaac Newton (Rubio, n.d.). Galilei concluded that all bodies, regardless of their size or mass, accelerate at the same rate (Cajal, n.d.). Similarly, he developed the concept of motion in terms of velocity by implementing inclined planes. Additionally, he formulated the concept of force as the cause of motion and established that the natural state of an object is either at rest or in uniform motion. For example, objects always have a velocity, and sometimes this velocity has a magnitude of zero, equivalent to being at rest. Finally, according to Cajal (n.d.), Galilei postulated that objects resist changes in motion, a concept known as inertia. Development of Mathematics During his adolescence, Galileo Galilei had a deep love for mathematics and believed that they could describe the laws of how the world worked (Rubio, n.d.). Mathematics were a fundamental tool for understanding nature because the world was governed by numbers. Therefore, according to Rubio (n.d.), he was one of the first scientists to base his research on mathematics, using numbers as tools to analyze and understand natural phenomena. Precursor of the Thermometer Galileo Galilei is credited with the creation of the precursor to the thermometer, known as the thermoscope (Rubio, n.d.). This device consisted of a tube ending in a large sphere, filled with water or alcohol (Aguirre, 2019). It used hot air to move the water through the tube, marked with a range of temperatures. According to Aguirre (2019), this discovery was the basis for the development of modern thermometers, making it a highly significant finding. References Cajal, A. (s.f.). Galileo Galilei: biografía, aportes y obras. Lifeder. Recuperado 16 de noviembre de 2021, de https://www.lifeder.com/aportaciones-galileo-galilei/ Farias, I. (2021). Principales aportaciones de Galileo Galilei a la ciencia. Psicocode. Recuperado 16 de noviembre de 2021, de https://psicocode.com/ciencia/aportaciones-galileo-galilei/ Fernández, T., & Tamaro, E. (2004). Galileo Galilei. Biografías y Vidas. Recuperado 16 de noviembre de 2021, de https://www.biografiasyvidas.com/monografia/galileo/ Redd, N. T. (2017). Galileo Galilei: Biography, inventions & other facts. Space.Com. Recuperado 17 de noviembre de 2021, de https://www.space.com/15589-galileo-galilei.html Rubio, N. M. (s. f.). Galileo Galilei: biografía y aportes a la ciencia de este investigador. Psicología y Mente. Recuperado 16 de noviembre de 2021, de https://psicologiaymente.com/biografias/galileo-galilei

Sometimes, Goclenius is attributed with the invention of the term "psychology" in 1590. However, it is important to note that the word had already been used by Marko Marulić almost seven decades earlier (Kühner, 2017). Additionally, Goclenius is recognized as one of the first writers to use the term ontology. According to Kühner (2017), he held the position of professor of philosophy, logic, metaphysics, and ethics at the Philipps University of Marburg, and he wrote about logic, philosophy, and psychology at a time when the Malleus Maleficarum continued to be a bestseller, surpassed only by the Bible. Biography On March 1, 1547, the scholastic philosopher Rudolphus Goclenius the Elder was born in Korbach, Germany (Sack, 2021; Kühner, 2017). He was the son of respected burghers from Korbach in the County of Waldeck, an independent territory of the Holy Roman Empire, located on the Eder River, northwest of the present-day state of Hesse, Germany (Sack, 2021). In this town, he first attended the local school until 1564 and then studied in Erfurt before continuing his studies in Marburg from 1567. In 1568, he returned to Korbach and taught at his former institute. On April 9, 1570, he married Margaretha Emmerich, whom he possibly knew from his childhood. On July 31, 1570, he enrolled at the University of Wittenberg, where he earned the title of Magister on March 13, 1571, and taught until 1573. Subsequently, as per Sack (2021), he returned to his hometown, Korbach, and served as the director of the municipal school from 1573 to 1575. In 1575, the landowner William IV of Hesse-Kassel appointed him rector of the Kassler Pädagogium (Sack, 2021). During this time, he adopted the Latinized academic name Goclenius. In Kassel, according to Sack (2021), he leaned towards the philosophical direction of Ramism, named after the famous French humanist, Petrus Ramus, without completely rejecting Melanchthonism, which he had encountered during his school and study days. By the late 16th century, the philosophical world was divided into two hostile camps: the Ramists and the antiramists (Sack, 2021). However, according to Kristic (2001), due to his philosophical attitude, Goclenius belonged to the so-called "semiramists," i.e., the group of Aristotelians who were in an intermediate position between those advocating the dialectical interpretation of Aristotle's knowledge and those advocating his Averroistic exposition. In Goclenius's circle of friends were admirers of Ramus, such as Hieronymus Treutler and Rudolph Snellius; opponents of Ramus, like Nikodemus Frischlin and Philipp Scherbius; semiramists, like Bilstein; independent thinkers, such as Nicolaus Taurellus, and opponents like Johannes Weber, Johannes Hesselbein, Libavius, and Daniel Hofmann (Sack, 2021). Probably, this was the reason why the inhabitants of Korbach wanted to attract him back to the city in 1580, where the Gymnasium of Korbach had just reopened to teach the spirit of Ramist principles. However, the landowner did not want to lose his scholar and refused to allow him to continue but agreed to transfer him to Marburg, Germany. According to Sack (2021), despite offers from the universities of Bremen, Herborn, Lemgo, and even Wittenberg, the most important of all Protestant universities at the time, they failed to lure him away from Marburg. In 1581, Goclenius accepted the call as a philosophy professor (Sack, 2021). From 1589, he taught logic and mathematics as a professor, and from 1603, he taught logic and ethics. Goclenius's reputation attracted numerous students to Marburg, not only from all parts of Germany but also from foreign countries. Along with the jurist Hermann Vultejus, he exerted a significant influence on the development of the University of Marburg. Both advised the landowner Moritz of Hesse. In 1618, Moritz sent Goclenius with three theologians to the Synod of Dordrecht. According to Sack (2021), although Goclenius was not a genius or had a deep or original nature, he possessed broad erudition, quick wit, dialectical sharpness, clarity, and lightness of exposition, unusual even in those times of polymathy, along with a kind, fresh, and peaceful demeanor. The last years of his life were embittered by multiple dark events (Sack, 2021). In 1621, he lost his eldest son, Rudolph, who had worked alongside him for 13 years as a physics professor at the University of Marburg. Two years later, the horrors of the Thirty Years' War descended upon Hesse. A conflict over inheritance between Moritz and Louis of Hesse-Darmstadt led to Tilly and his execution army arriving in Marburg in 1624. Eventually, the city and the university came under the possession of the House of Darmstadt, and as a result, many professors were dismissed. The burden Goclenius carried is reflected in a poem from 1624, expressing exhaustion from heart-wrenching concerns, sick in the soul amid the turmoil of all things sacred and profane. According to Sack (2021), he died with his strength almost intact but full of pain for the state of his homeland on June 8, 1628, at the age of 81. The Christian Aristotle He was widely known in his time and celebrated as the "Plato of Marburg" or the "Christian Aristotle" (Sack, 2021). In addition to various treatises in the field of logic and a philosophical dictionary, he published a treatise in the year 1590, titled "Psychologia: hoc est, de hominis perfectione, animo, et in primis ortu hujus" (Kristic, 2001). According to the available information, this is the earliest preserved printed book containing the word "psychology" in the title (Kristic, 2001). In this context, the term psychology refers to both a research subject and the research itself (Sack, 2021). He is also recognized for being the first to separate ontology from special metaphysics, a practice that became common in the teaching of philosophy after him. Apart from that, he proved to be incredibly knowledgeable and versatile. However, it cannot be said that he had much intellectual independence. According to Sack (2021), his descriptions often appear too general and nebulous, and he frequently resorted to erudite tricks. Ontology The term ontology seems to have been used for the first time in German by Goclenius (Sack, 2021). In a similar time period, there is a reference to Jacob Lorhard, who worked as a professor in San Gall, Switzerland. Johann Georg Walch, in his work "Philosophisches Lexicon," defines ontology as the doctrine of the end, a designation that some recent philosophers have interpreted as the science dealing with the end in general and its properties. However, the term "ontology" was first used in its proper sense by Goclenius in 1613 and by Clauberg in 1656. Similarly, Goclenius separated ontology from metaphysics. According to Sack (2021), in classical philosophical systematic, ontology is considered a fragment of metaphysics, i.e., general metaphysics as opposed to special metaphysics, which deals with topics like God, the soul, and the world. Despite the term "ontology" being introduced relatively late in the history of philosophy, its subject matter was already addressed in antiquity (Sack, 2021). According to Sack (2021), Rudolphus Goclenius distinguished ontology as "philosophia de ente" based on its object's relationship to the matter of "scientia transnaturalis," interpreted as the doctrine of God and angels. A Theorist of Witchcraft As a theorist of witchcraft, he gained some importance thanks to his discourse "Oratio de natura sagarum in purgatione et examinatione per frigidam aquis innatantium" in the year 1583, which was also printed in the year 1590 (Sack, 2021). In this discourse, the doctrine of the water trial was addressed. This ancient divine judgment had been reintroduced as a "witch's bath" during the witch hunts that took place in the early modern period. As a result, an academic dispute arose regarding its legality. Goclenius primarily argued against Wilhelm Adolf Scribonius, who vehemently defended the legality of the water trial for the crime of witchcraft. However, according to Sack (2021), Goclenius turned out to be a proponent of the witchcraft doctrine, in total agreement with the explanations present in the Malleus Maleficarum. Referencias Kühner, W. (2017). On Rudolphus Goclenius and the latest news about the “folk on the dark side”. Medium. Recuperado 4 November 2021, a partir de https://medium.com/kühner-kommentar/on-rudolphus-goclenius-and-the-latest-news-about-the-folk-on-the-dark-side-54a867b46b7f Kristic, K. (2001). Classics in the History of Psychology. Psychclassics.yorku.ca. Recuperado 4 November 2021, a partir de https://psychclassics.yorku.ca/Krstic/marulic.htm Sack, H. (2021). Rudolph Goclenius the Elder and the Philosophical Discipline of Ontology. SciHi Blog. Recuperado 4 November 2021, a partir de http://scihi.org/Rudolph-goclenius-ontology/

Giambattista della Porta, recognized for his unique and extensive ingenuity, showed a deep interest in various disciplines, ranging from cosmology, meteorology, and physics to biology, human psychology, moral philosophy, and politics (Fernández & Tamaro, 2004; Kodera, 2021). He stood out as a prolific author on topics that, at the time, were associated with alternative currents to Aristotelian natural philosophy (Kodera, 2021). According to Kodera (2021), this versatility allowed him to become one of the most celebrated and successful figures in the intellectual life of the second half of the 16th century and beyond. Della Porta was constantly at the intersection between science and magic, and between faith and superstition (Fernández & Tamaro, 2004). Despite this duality, he was one of the authors who contributed the most to the formation of modern scientific thought during the Counter-Reformation. His work "Natural Magic" brought him European fame and is considered the best reflection of his personality. Despite his apparent naivety and enthusiasm in the pursuit of the philosopher's stone, as well as the mysterious atmosphere that sometimes surrounded his discoveries, della Porta demonstrated rigor in his research, and some of his conclusions were of great importance. According to Fernández & Tamaro (2004), among his most notable achievements is the invention of the camera obscura, and, according to some authors, he played a prominent role in the construction of the first telescopes. Biography Giambattista della Porta, who was born in Vico Equense in 1535, was the son of Nardo Antonio della Porta, a man of considerable wealth and significance, owning lands and ships (Buzzi, 2016; O'Connor & Robertson, 2010). Since 1541, his father served Emperor Charles V as Scrivano di Mandamento, meaning the emperor's secretary in charge of civil affairs before the vicariate. His mother was the sister of Adriano Guglielmo Spadafora, a learned man working as a curator in the archives of Naples. His education was largely thanks to his father, an intellectual whose home became a meeting point for philosophers, mathematicians, poets, and musicians (O'Connor & Robertson, 2010). According to Buzzi (2016), della Porta and his siblings were raised to be knights, learning to dance, ride, participate in tournaments and games, behave properly, and dress appropriately to excel in all these pursuits. In 1558, when della Porta was twenty-three, he published the four volumes of "Magiae naturalis, sive de miraculis rerum naturalium" (O'Connor & Robertson, 2010). In this book, he examined the natural world, asserting that it could be manipulated by the natural philosopher through theoretical and practical experiments. The work covers various topics, including demonology, magnetism, and the camera obscura. O'Connor & Robertson (2010) mention that originally written in Latin, the work was later translated into French, Italian, and German, becoming a widely read book. In 1560, a society was formed under the direction of Giambattista della Porta, known as the Accademia dei Segreti or the Otiosi (O'Connor & Robertson, 2010; Buzzi, 2016). This society, one of the first scientific communities in Europe, aimed to discover the secrets of nature (Buzzi, 2016). Anyone wishing to join this society had to demonstrate a new discovery in the natural sciences. According to Buzzi (2016), this early academy had to dissolve when its members were suspected of dealing with the occult. In 1563, he published "De Furtivis Literarum Notis," a work related to cryptography, where he specified the first known substitution cipher (Buzzi, 2016). During the Spanish Inquisition, some of his friends were imprisoned. However, to enter the prison, everything was checked except for eggs. According to Buzzi (2016), this led him to invent a method for writing secret messages inside eggshells using a mixture of vegetable pigments and alum. In 1566, he published "Arte del ricordare," a work describing how to use mnemonic devices to enhance memory (O'Connor & Robertson, 2010). According to Giambattista della Porta, to organize memory, one must build a mental gallery populated with striking images of people or groups of people (Kodera, 2021). Corresponding to O'Connor & Robertson (2010), it is concluded from this work that della Porta's memory was more due to his classification and organizational skills than to natural genius. In November 1579, he was invited to join the service of Luigi, Cardinal d'Este (O'Connor & Robertson, 2010). In need of a sponsor, he moved to Rome two months later and lived in the Palazzo d'Este. There, he carried out his scientific work financed by the cardinal, although causing inconveniences as he insisted on going to bed immediately after dinner, woke up very early, and made a lot of noise when studying before breakfast. Similarly, according to O'Connor & Robertson (2010), he demanded complete silence whenever he was working or sleeping. After a period of illness, della Porta joined the service of the cardinal in Venice in December 1580 (O'Connor & Robertson, 2010). There, he worked with parabolic mirrors and lenses, discovering that the Venetian experience with glass was very useful. He spent time at the court of Duke Alfonso II d'Este in Ferrara, but in April 1581, he returned to Naples, though he continued working for the cardinal. Like his earlier academy, his house became a meeting place for the scholars of the region. Like many scientists of the time, he dedicated himself to trying to transform common metal into gold and believed he had found the secret. However, according to O'Connor & Robertson (2010), after more experiments, della Porta discovered that his method was unsuccessful. In 1583, he published "De humana physiognomonia" (Buzzi, 2016). In this work, he explained his interpretation of how the behavior of animals and humans is associated with physical appearance. He based it on the idea that physical traits are related to the moral and psychological aspects of a person (Buzzi, 2016). This theme was treated with some suspicion by the Roman Catholic Church, which at that time included many works in the Index of Forbidden Books (O'Connor & Robertson, 2010). However, after a long wait of three years, the book was approved by official censors. During the research for his work, he visited various places, including, of course, the public prison (Buzzi, 2016). According to Buzzi (2016), he compared his findings with animals, found connections, and provided interpretations. In 1588, he collected rare botanical specimens and cultivated exotic plants (Buzzi, 2016). In his work "Phytognomonica," he listed plants according to their geographical location and recorded the first observations of fungal spores, making him a pioneer in mycology. In 1589, on the eve of the scientific revolution, he was the first to experimentally challenge the ancient claim that garlic could demagnetize magnets. This fact represents one of the first instances where the authority of ancient authors was replaced by scientific claims supported by experiments. The Secretorum Natura Academy was replaced by the Accademia dei Lincei in 1603. This new academy was founded by Federico Cesi, along with three other friends. According to Buzzi (2016), the four founders chose the name Lincei from della Porta's book "Magia naturalis," which has an illustration of the legendary lynx on the cover. In 1611, he joined the Accademia dei Lincei, which became one of the most relevant academies of its time (Buzzi, 2016). In 1874, after the unification of Italy, Quintino Sella, a Piedmontese, transformed the Accademia dei Lincei into the Accademia Nazionale Reale dei Lincei, making it the official scientific academy of the country (Buzzi, 2016). The last years of his life were dedicated exclusively to theater and studies on the atmosphere (Fernández & Tamaro, 2004). According to Kodera (2021), in February 1615, della Porta passed away in his daughter Cinzia's house. Works The treaty titled "De la magia natural," composed of four volumes and published in Naples in the year 1558, is a peculiar work that combines magical practices with scientific essays (Fernández & Tamaro, 2004). This work gathers a series of interesting experimental observations, such as recipes to blush the face, to generate beautiful children, or to cultivate pitless peaches, as well as descriptions of monstrous creatures, including a flying dragon. Also, according to Fernández & Tamaro (2004), the creator makes significant observations about mirrors called "ustorious," that is, curved. In the 1589 edition, it is mentioned that, in addition to explaining a kind of magic lantern, the author describes the effect of lenses (Fernández & Tamaro, 2004). He claims that with concave lenses, objects can be seen smaller but sharper, and with convex lenses, the size of objects can be increased, although they will appear blurry. In this way, he discovered that by combining concave and convex lenses, objects will be perceived both sharper and larger, both near and distant objects. This finding allows us to declare that, before Galileo Galilei, Giambattista della Porta managed to build a long-range telescope with a divergent eyepiece. However, according to Fernández & Tamaro (2004), some authors, such as Giambattista de Nelli, argue, rightly, that Giambattista della Porta understood composite lenses but did not construct or imagine a true telescope. In connection with this last topic, the author also dealt with the nine books that make up his work "De la refracción óptica," published in Naples in the year 1593 (Fernández & Tamaro, 2004). The first book deals with the phenomenon of refraction through the "crystal pile" or crystal sphere, and also through a half-sphere of crystal. This is followed by a set of five books dedicated to the structure and functioning of the eye, as well as the mechanism of vision. Finally, according to Fernández & Tamaro (2004), the eighth book deals with lenses, and the ninth with the rainbow and colors produced by refraction. This treaty represents a crucial period in the history of science (Fernández & Tamaro, 2004). Although the first seven books and the ninth are a compilation of knowledge from the time, an innovative criterion can be found in all of them, something uncommon during the 16th century. He highlighted theoretical deficiencies and weaknesses that followers of the ideas of the time believed they had to hide. For example, he announced that, in terms of refraction, analysis could describe many things that are still unclear and eliminate many errors. However, the greatest interest lies in the eighth book "De los lentes." This is the first study attempting a theory of lenses. In fact, the lenses that have been used to correct the vision of presbyopes since the 13th century have been ignored by the scientific community. There is no mention of them until della Porta mentioned them, and only now does he aspire to establish a theory based on the knowledge available about the "crystal pile." Finally, he is attributed twenty-nine comedies, of which fourteen are preserved (Fernández & Tamaro, 2004). Among them, "Cintia," "El astrólogo," "La Chiappinaria," "El moro," "Olimpia," and "Los dos hermanos rivales" can be mentioned. In addition to these works, Fernández and Tamaro (2004) mention the tragicomedy "Penélope" and a tragedy inspired by the life of Saint George. References Buzzi, A. (2016). La Phisiognomia de Giovanni Battista della Porta. Almarevista.com. Recuperado 9 November 2021, a partir de http://almarevista.com/revista/wp-content/uploads/2020/06/ALMA.V2N4.43-57.pdf Fernández, T., & Tamaro, E. (2004). Biografia de Giambattista della Porta. Biografiasyvidas.com. Recuperado 9 November 2021, a partir de https://www.biografiasyvidas.com/biografia/p/porta_giambattista.htm Kodera, S. (2021). Giambattista della Porta. Plato.stanford.edu. Recuperado 9 November 2021, a partir de https://plato.stanford.edu/entries/della-porta/ O'Connor, J., & Robertson, E. (2010). Giambattista della Porta - Biography. Maths History. Recuperado 9 November 2021, a partir de https://mathshistory.st-andrews.ac.uk/Biographies/Porta/

The topic of death remains a taboo in society, especially when discussing it with a child (Francisco, 2018). In many cases, when a loved one or a friend becomes ill or passes away, children are often kept in the dark without a clear explanation of what is happening. This practice extends even to cases where the child themselves is ill or in a terminal phase, with some families choosing not to provide them with information about their situation. Therefore, in accordance with Francisco (2018), it is common for children to feel confused about the concept of death. It is important to note that boys and girls do not understand death in the same way as adults (Carrera et al., 2020). Their understanding of the concept evolves throughout their development, shaped by their experiences, the questions they ask, the responses they receive, and the interests and concerns that emerge during their life cycle (Carrera et al., 2020). Consequently, effective communication and honest information tailored to the child's needs are essential for them to face their fears appropriately (Francisco, 2018). But how do you talk to a child about death? At what age does a child have similar ideas about death as an adult? How Does a Child Acquire the Concept of Death? It is understood that boys and girls face death differently, depending on their cognitive maturity (Francisco, 2018). This implies that children's understanding of the concept of death is based on their developmental level rather than their chronological age. Therefore, in accordance with Reguera (2019), understanding the grieving process in children will enable us to provide better support during these difficult times. Barbara Kane describes three stages in the development of the concept of death in children (Francisco, 2018). The first stage is characterized by the acquisition of separation concepts, meaning the understanding that the deceased no longer live among us, and the lack of movement, meaning that the deceased remain motionless. In the second stage, the concepts of universality, i.e., that death will reach us all, and the cessation of bodily activity are distinguished, along with irreversibility, i.e., that death is final, and causality, initially related to external causes such as accidents or illness. In the final phase, the child can think about death in an abstract way, almost like an adult. As can be observed, the concept of death is defined multidimensionally by integrating the understanding of three basic concepts: universality, irreversibility, and cessation of bodily processes. But, according to Francisco (2018), at what approximate age are each of these concepts acquired? When Does a Child Acquire the Concept of Death? Prelinguistic Stage (0 - 18 Months) At this moment, there is a relative lack of understanding of the meaning of death, so it is not considered as something final (Figueroa, Cáceres & Torres, n.d.). Even though death may not be fully comprehended at these ages, infants can perceive the emotions of the person caring for them. Therefore, it is crucial that primary caregivers recognize their own emotional needs. It is also essential for the primary caregiver to strive to maintain as many routines as possible (Figueroa, Cáceres & Torres, n.d.). In the absence of the loved one, the routine provides the infant with a sense of security (Carrera et al., 2020). Otherwise, the child may experience a certain degree of confusion, restlessness, and uncertainty when these routines are disrupted or canceled (Carrera et al., 2020). In short, according to Figueroa, Cáceres & Torres (n.d.), routine serves as a protective force for infants amid significant disruptions. On the other hand, death is equated with separation in a concrete sense, from the perception that something or someone is missing (Sánchez, 2013). In this way, separation is experienced as abandonment and represents a threat to security (Sánchez, 2013). Therefore, it is important to avoid physical separation, provide additional physical care to comfort the child, and enhance their sense of security (Figueroa, Cáceres & Torres, n.d.). This way, the little ones will feel loved and protected by someone else (Reguera, 2019). However, in line with Reguera (2019), it is important to note that this will not make them stop expecting the deceased to return, but it will help them overcome the pain and gradually return to normalcy. Preschool Stage (18 Months - 5 Years) From the age of two, when language development significantly expands, preschoolers tend to perceive death as a reversible, transient, and impersonal phenomenon (Paris, 2011). As a result, it is common for them to insist on the possibility of seeing the deceased person again, even after being told that this will not happen (Reguera, 2019). At this stage of life, there is a belief that illness is caused by external factors or accidents (Francisco, 2018). Additionally, according to Francisco (2018), death is interpreted as a dream characterized by the loss of mobility, separation, or temporary malfunction. This stage is also characterized by magical thinking, meaning that children believe the dead breathe, eat, and move from one place to another (Francisco, 2018). This kind of thinking can lead them to experience illness as a punishment for their misbehavior or bad thoughts (Francisco, 2018). Since children at this stage are concrete thinkers, interpreting things as they appear, it is crucial that information about death is provided to them in understandable and simple language (Figueroa, Cáceres & Torres, n.d.). Therefore, euphemisms like "went to sleep" or "traveled to the beyond" should be avoided, as these phrases may not be understood and, in some cases, may induce fear of sleeping or during long journeys (Salek & Grinsburg, 2016). Instead, according to Figueroa, Cáceres & Torres (n.d.), they should hear that their loved one has died and that means they won't be able to see them again. During this stage, questions about the whereabouts of the deceased or when they will return may persist (Salek & Ginsburg, 2016). However, it is necessary to provide clear messages, which can be softened with the idea that memories will endure forever (Figueroa, Cáceres & Torres, n.d.). The decision to use religious explanations rests with the parents, but relying solely on religious explanations at this stage may be ineffective, as children require more concrete explanations about the physical reality of death (Salek & Ginsburg, 2016). Considering that, at this age, children cannot always express their thoughts and fears, these often emerge at unexpected moments, such as during their playtime (Figueroa, Cáceres & Torres, n.d.). According to Salek & Ginsburg (2016), it is important to emphasize that play is the language of childhood; therefore, caregivers should pay attention to what children are trying to communicate through it. Moreover, some children may revert to immature behaviors, such as baby talk, thumb-sucking, becoming clingy, or irritable (Figueroa, Cáceres & Torres, n.d.). Others may have outbursts of anger. However, in line with Figueroa, Cáceres & Torres (n.d.), it is important to consider that these behavior changes are likely manifestations of unexpressed emotions, such as confusion or frustration. School - Age Stage (From 5 Years Old) During the school - age stage, children begin to show curiosity about death and social relationships (Francisco, 2018). At this age, they already understand that certain internal factors can cause illnesses. However, they often think that death is selective, affecting only the elderly (Francisco, 2018). Therefore, it is common for them to believe they can avoid death through their cleverness (Paris, 2011). At this stage, children also tend to personify death, associating it with a skeleton or the angel of death (Paris, 2011). These images can trigger nightmares in some children (Paris, 2011). For this reason, it is crucial to provide simple and honest explanations about what has happened and then ask them what they understand (Figueroa, Cáceres & Torres, n.d.). According to Salek & Ginsburg (2016), it is essential for adults to take the time to clarify any misunderstandings or misinterpretations. During the school - age stage, children may need help from adults to find the right words to express their emotions and find ways to feel better (Figueroa, Cáceres & Torres, n.d.). Therefore, primary caregivers should provide repeated opportunities for children to feel comfortable talking about their feelings (Salek & Ginsburg, 2016). Common reactions to death at these ages may include difficulty concentrating in school, sleeping problems, and recurrent thoughts about death (Figueroa, Cáceres & Torres, n.d.). In accordance with Figueroa, Cáceres & Torres (n.d.), they may experience physical reactions such as stomachaches and headaches that can be triggered by staying in places that remind them of the deceased person. Between 7 and 13 Years Old In this phase, it is observed that children begin to fully understand that death is irreversible, that all living beings die, and that they will also die someday (Paris, 2011). This understanding often leads them to frequently elaborate philosophical ideas about life and death or seek the meaning of life, although their anchoring in the present prevents them from imagining that someday it will come for them. Facing and fearing death, they are trying to overcome their fears and "control" mortality (Paris, 2011). At this stage, the structuring of the mind allows them to understand abstract processes, meaning they differentiate between fantasy and reality (Carrera et al., 2020). Moreover, they become aware of violence, differences in society, and the difficulties that may arise. Therefore, according to Carrera et al. (2020), this is a stage where high levels of frustration can develop. On another note, children between seven and thirteen years old perceive their surrounding environment much better and, therefore, may be more prone to seek companionship in grief (Carrera et al., 2020). Adults in their surrounding environment must be very clear that, having an understanding of abstract processes, such as the rituals performed after a person's death, can be explained to them without fear of the purpose of these rituals and how they help us bid farewell to the loved one. In line with Carrera et al. (2020), when faced with their questions or concerns, it is fundamental to clarify to children in this stage how the body or organs stop functioning, as this will help them better understand that death is not a consequence of their thoughts. During this stage, support networks are expanding, with the presence of friends and authority figures outside the family becoming more important. Therefore, a child should not be forced to isolate themselves to prevent them from expressing their feelings or finding peace by force or habit. This is a crucial moment to let them know how important they are and how good it is to have them close. Additionally, it is possible to work with children to build or strengthen a self-care structure with communication and respect-based strategies, keeping them away from risky behaviors. Also, according to Carrera et al. (2020), it is important to prevent the uncertainty that generates frustration and a lack of understanding of death from affecting them and preventing them from engaging in activities they used to do in their daily lives. Communication with the Child About the End of Life Talking about death with children is one of the most challenging situations that adults face (Francisco, 2018). It is evident that the child has the capacity to learn about illness, even if there is an attempt to hide it. Therefore, it is important to discuss these topics with them, always in a manner suitable for their level and respecting their needs. By using language that is easy for the child to understand and allowing them to share drawings, stories, or narratives, they are given the opportunity to explore their fears. According to Francisco (2018), this will provide comfort, as well as equip them with arguments to counter the "temptation" to believe that they are responsible for someone's death due to misbehavior. One of the most important communication skills will be active listening since many boys and girls talk about death through puzzles, story characters, television series, or comics (Francisco, 2018). Similarly, non-verbal communication is crucial, as children may use posture, tone of voice, or gaze to express their fears or unpleasant sensations that they cannot articulate with words. Finally, it is necessary to be attentive and, at the same time, be mindful of how one communicates with them. Ideally, communication should be calm and without dramatization. In this way, in line with Francisco (2018), concern or sadness can be expressed, but with confidence, assuring them that they will be accompanied at all times. References Carrera, M., Gutiérrez, K., Hernández, O., Ibarra, S., Poiré, R., & Sabbagh, L. et al. (2020). Recomendaciones para Abordar el Duelo y la Muerte con Niñas, Niños y Adolescentes. Enduelo.org. Recuperado 7 octubre 2021, a partir de https://enduelo.org/descargas/guia_ninos_enDuelo.pdf Figueroa, M., Cáceres, R., & Torres, A. Duelo: Manual de Capacitación Para Acompañamiento y Abordaje de Duelo. Unicef.org. Recuperado 4 octubre 2021, a partir de https://www.unicef.org/elsalvador/media/3191/file/Manual%20sobre%20Duelo.pdf Francisco, J. (2018). El Concepto de Muerte en los Niños y Adolescentes. La Mente es Maravillosa. Recuperado 4 octubre 2021, a partir de https://lamenteesmaravillosa.com/el-concepto-de-muerte-en-los-ninos/ Paris, E. (2011). Etapas del Niño en la Comprensión de la Muerte. Bebesymas.com. Recuperado 4 octubre 2021, a partir de https://www.bebesymas.com/desarrollo/etapas-del-nino-en-la-comprension-de-la-muerte Reguera, L. (2019). Comprender el Duelo de Nuestros Pequeños: Una Ayuda en Momentos Difíciles. La Mente es Maravillosa. Recuperado 4 octubre 2021, a partir de https://lamenteesmaravillosa.com/comprender-duelo-pequenos-una-ayuda-momentos-dificiles/ Salek, E., & Ginsburg, K. (2016). Cómo Entienden los Niños la Muerte y qué Debe Decir. HealthyChildren.org. Recuperado 4 octubre 2021, a partir de https://www.healthychildren.org/Spanish/healthy-living/emotional-wellness/Building-Resilience/Paginas/how-children-understand-death-what-you-should-say.aspx Sánchez, I. (2013). La Vinculación Afectiva y el Camino de la Vida. Apego, Pérdida y Psicopatología Infantil. Psiquiatria.com. Recuperado 5 October 2021, a partir de https://psiquiatria.com/trabajos/usr_555289354.pdf

He is known as Paracelsus, although his real name was Theophrastus Philippus Aureolus Bombastus von Hohenheim (Sánchez, 2019). He stood out as one of the most fascinating personalities in the history of medicine and science in general. Some people considered him a bit eccentric, visionary, and undoubtedly extremely ingenious. He was characterized by his intellectual ambition. He is remembered as a fervent seeker of the philosopher's stone, a mysterious substance believed to have the ability to transform lead into gold. In correspondence with Sánchez (2019), he also aspired to discover the elixir of eternal youth and worked tirelessly to achieve it. During his adventures, he became an exceptional researcher (Sánchez, 2019). For some, he was a science revolutionary and a pioneer in pharmacology and modern medicine, but for others, he never ceased to be an esoteric figure (Gargantilla, 2021). His life was filled with controversial moments, including questioning and even burning classical texts on medicine and science, belittling scientific figures considered untouchable, and breaking with traditional practices (Bertran, n.d.). All of this contributed to making him a legend in the field of medicine. Additionally, according to Bertran (n.d.), he was not only a precursor in the development of what is now known as "medicines," but he was also the first to describe the symptoms of some infectious diseases, establish the connection between the mind and body, and develop treatments for diseases considered incurable. Biography Born on November 10, 1493, in Einsiedeln, a town in central Switzerland (Bertran, n.d.), he hailed from a family with a tradition in medicine, including his father, which sparked his interest in the discipline (Sánchez, 2019). After the death of his mother when he was young, his father moved to Villach, in southern Austria (Hargrave, 2021). There, he attended Bergschule, an institution founded by the merchant banking family Fugger from Augsburg, where his father taught theory and practical chemistry. At Bergschule, young individuals were trained to be supervisors and analysts of gold, tin, and mercury mining operations, as well as iron, alum, and copper sulfate minerals (Hargrave, 2021). It was here that he developed a profound passion for nature and science in general (Bertran, n.d.). Bertran (n.d.) mentions that due to this, and because his family enjoyed a good social standing, he received a solid education in astronomy, music, arithmetic, grammar, among other disciplines. During his youth, he worked as an analyst in the mines (Sánchez, 2019). In this environment, he learned about metals "growing" in the earth, observed the transformations of metallic components in smelting furnaces, and possibly pondered the transmutation of lead into gold, a conversion believed possible by alchemists of the time (Hargrave, 2021). In correspondence with Hargrave (2021), these experiences allowed him to understand metallurgy and chemistry, likely laying the groundwork for his later discoveries in the field of chemotherapy. In 1506, he enrolled at the University of Basel to continue his studies in chemistry and medicine (Bertran, n.d.). It is believed that he obtained his medical degree from the University of Vienna in 1510 (Hargrave, 2021). Later, he went to the University of Ferrara in Italy, where he expressed his rejection of the prevailing opinion that the stars and planets controlled all parts of the human body. It is believed that he received the title of doctor from the University of Ferrara in 1516 and presumably started using the name "para-Celsus," meaning above or beyond Celsus. According to Hargrave (2021), his new name reflected the fact that he considered himself even more important than Aulus Cornelius Celsus, a renowned Roman medical writer of the 1st century. After receiving his doctorate, he decided to embark on a 12-year pilgrimage that took him to numerous countries, including England, Spain, Turkey, and Egypt (Bertran, n.d.). During this extensive journey, he began to gain followers by sharing his ideas on how philosophers and scientists were wrong in their approach to medical studies. Contrary to popular belief, he was convinced that diseases arose from external factors, not internal changes. Consequently, he deemed it impossible to cure diseases with herbs, ointments, let alone with purges and other traditional "treatments." Instead, according to Bertran (n.d.), he argued that the cure for all these ailments lay in nature, not in plants, but in minerals. For this reason, everything explained up to that point was considered incorrect. After this pilgrimage, he returned to Switzerland, where he was appointed a professor at the University of Basel in 1526 (Bertran, n.d.). In this city, he dedicated much of his professional life to dismantling classical medicine and trying to demonstrate that the solution to medical problems lay in minerals and chemistry. To combat classical medicine, he even publicly burned the books of some of the most distinguished philosophers and scientists in history. It is believed that he managed to burn some texts of Hippocrates, considered the father of medicine. He published various works combining alchemy and medicine, in which he argued that each disease should have its own treatment, meaning universal remedies could not exist. He described how to create "medications" by combining different types of chemicals and metals. However, according to Bertran (n.d.), it is clear that he made many enemies, both among physicians and "pharmacists." Because of this, he was forced to leave Basel in 1528 and return to different countries, repeatedly changing his residence (Bertran, n.d.). During this time, he continued to challenge classical medicine and advocate for a new vision in which he argued that chemistry would provide the answer to how to cure the diseases that had plagued the world. Although he made incredible advances in the field of medicine, not all of his research turned out to be valid. Among them, he claimed that surgery was useless because human anatomy had no significance in the development of diseases. In this, he was mistaken, but in his progress as an alchemist lies the origin of modern medicine (Bertran, n.d.). Finally, in May 1538, he returned to Villach to see his father but discovered that he had died four years earlier (Hargrave, 2021). According to Hargrave (2021), in 1541, he died under mysterious circumstances in Austria, where he had assumed a position under the Prince-Archbishop, Duke Ernest of Bavaria. The "Tria Prima" Paracelsus developed a hypothesis in an attempt to explain the nature of medicine (Gargantilla, 2021). According to his theory, all substances from the mineral, animal, and vegetable realms were composed of the "tria prima," namely, sulfur, mercury, and salt. These elements combine in different proportions but always in a stable manner. He considered mercury to be the principle of liquidity and volatility; sulfur represented heat and combustion, and salt was to be understood as the principle of resistance to fire. When, for some reason, the proportions of tria prima in the organism were altered, diseases would arise. According to Paracelsus, these conditions could be cured by ingesting certain chemicals that would restore balance. As per Gargantilla (2021), an overdose of mercury could trigger paralysis and melancholy; an excess of sulfur could lead to heat and fever in patients, while an imbalance toward salt could result in dropsy and diarrhea. Development of the First Pharmaceuticals Paracelsus, despite his controversial figure, is undoubtedly recognized as a person ahead of his time (Bertran, n.d.). Like those who leave a mark, he dared to question the foundations of everything. One of his significant contributions was confirming that, although sometimes treatments for diseases can be found in plants, as a general rule, one had to resort to minerals and chemicals, something that was considered inconsistent until then. Thanks to his knowledge in alchemy, Paracelsus developed various preparations using salts, iron, mercury, antimony, lead, sulfur, among others. This laid the groundwork for modern pharmacology. Finally, in line with Bertran (n.d.), he was the first to consider that certain poisons, in the right doses, could cure diseases. Clinical Description of Diseases Up to that moment, diseases and their nature were an absolute enigma (Bertran, n.d.). Paracelsus was one of the pioneers in proposing that diseases did not originate from internal changes in the individual but rather came from the external environment. This approach represented a complete paradigm shift, contradicting existing beliefs (Bertran, n.d.). Among Paracelsus's most notable contributions to medicine of his time are the first clinical descriptions of syphilis and goiter, as well as the introduction of new treatment methods based on minerals such as lead or mercury (Bertran, n.d.; Fernández & Tamaro, 2004). However, some of his writings resembled homeopathy more than conventional medicine (Bertran, n.d.). Recently, in line with Hargrave (2021), he asserted that the "miner's disease," or silicosis, resulted from inhaling metallic vapors and was not a punishment for sins committed. Denial of Universal Remedies Until that moment, the belief in the existence of universal remedies capable of curing a wide variety of diseases persisted (Bertran, n.d.). However, Theophrastus Philippus Aureolus Bombastus von Hohenheim was the first to contradict this notion. This pioneer argued that each disease was unique, and therefore, the remedy to cure it should be equally specific. According to Bertran (n.d.), this assertion has been thoroughly validated. Defense of Experimentation as a Scientific Method Theophrastus Philippus Aureolus Bombastus von Hohenheim, renowned for his staunch defense of experimentation as the only way to advance in medicine and science in general, is a perfect example of the application of the scientific method, which remains absolutely valid to this day (Bertran, n.d.). In accordance with Bertran (n.d.), he maintained that the only way to make genuine discoveries was to formulate a theory and then experiment to confirm or refute it. Defense of the Union Between Mind and Body Theophrastus Philippus Aureolus Bombastus von Hohenheim, known for pioneering the connection between the emotional and the physical, advocated the idea that emotions and mental state can play a crucial role in determining an individual's susceptibility to developing diseases (Bertran, n.d.). At the time, in correspondence with Bertran (n.d.), this idea was considered incoherent; however, nowadays, it is widely accepted that the body and mind are intimately connected. References Bertran, P. (2021). Paracelso: biografía y resumen de sus aportes a la ciencia. Medicoplus.com. Recuperado 27 October 2021, a partir de https://medicoplus.com/biografias/paracelso}Fernández, T., & Tamaro, E. (2004). Biografia de Paracelso. Biografiasyvidas.com. Recuperado 27 October 2021, a partir de https://www.biografiasyvidas.com/biografia/p/paracelso.htm Gargantilla, P. (2021). Paracelso, el alquimista rebelde que revolucionó la farmacología. abc. Recuperado 27 October 2021, a partir de https://www.abc.es/ciencia/abci-paracelso-alquimista-rebelde-revoluciono-farmacologia-202109120038_noticia.html Hargrave, J. (2021). Paracelsus. Encyclopedia Britannica. Recuperado 27 October 2021, a partir de https://www.britannica.com/biography/Paracelsus Sánchez, E. (2019). Paracelso, biografía de un alquimista y soñador. La Mente es Maravillosa. Recuperado 27 October 2021, a partir de https://lamenteesmaravillosa.com/paracelso-biografia-de-un-alquimista-y-sonador/

Many adults hold the belief that children do not understand death or are not affected by it, but this assumption is incorrect (Ortego, n.d.). It has been noted that children tend to live more in the present, have shorter attention spans, and easily get distracted, allowing them to "forget" their pain more often, giving the impression that nothing has happened. However, this does not imply that they have forgotten the deceased person or do not miss them (Ortego, n.d.). Therefore, it is important for adults to help children express their emotions (Taberno, 2019). Fortunately, it has been observed that the majority of children manage their grief without major complications. However, it is equally important to be aware of strategies to assist them and better understand the process of childhood grief. According to Taberno (2019), how adults manage their grief of losing someone will influence the grieving process of the children around them. Childhood Grief Grief is commonly associated with death, but this process also encompasses other forms of loss, such as the loss of a pet, the loss of a significant object, among others (Taberno, 2019). In essence, grief is the emotional adjustment process that follows any loss. Undoubtedly, the death of a loved one is the most challenging situation one has to face. Death evokes a range of emotions, such as pain, sadness, loneliness, among others, and all these emotions need to be expressed to be effectively managed (Taberno, 2019). How children manage these emotions depends on various factors, including their developmental stage, temperament, social environment, and, particularly, the attitude of the adults around them (Arbizu, Kantt & Cepeda, 2020). According to Sánchez (2013), how loss experiences are processed in childhood will determine the ability to cope with later experiences of loss. Generally, adults are not well-prepared to navigate grief, as they often avoid discussing death, abandonment, or separation (Taberno, 2019). However, children develop an understanding of illness and death through a process that depends on their developmental level and cognitive maturity (Ortego, n.d.). Hence, it is crucial that the child is accompanied by individuals who provide the necessary support and external defenses (Arbizu, Kantt & Cepeda, 2020). The actual disappearance of a significant external object brings about noticeable changes in their internal world, as they remain highly dependent on external objects for coherence. On the other hand, due to their more flexible ego defenses, children are equipped with greater resilience and adaptability. According to Arbizu, Kantt & Cepeda (2020), after the death of a parent, many children perceive changes in their daily lives to which they also need to adapt. The death of a parent, in particular, implies a reduction in family income, which can lead to a change of residence and, in this case, a change of school and the possible loss of friends (Arbizu, Kantt & Cepeda, 2020). The death of a mother often signifies a decrease in the quantity and quality of childcare. Therefore, psychological adjustment is related to the emotional impact that the event has on the surviving caregiver. Likewise, in line with Arbizu, Kantt & Cepeda (2020), it was found that psychopathology in adulthood, after the loss of a parent in childhood, correlates with the adequacy of care during that loss. In terms of behaviors, children may quickly return to activities such as watching television, playing, drawing, among others (Arbizu, Kantt & Cepeda, 2020). Sometimes, adults may not understand this and may perceive this behavior as if the child has already moved on from the deceased, but that's not the case. The adult behaves differently because if they start to enjoy some outings or moments, they might feel guilt or feel like they are betraying the deceased. Children's grief is expressed more through their bodies and behavior (Arbizu, Kantt & Cepeda, 2020). Therefore, it is important to encourage clear communication at the time of the death of a significant person for the child (Ortego, n.d.). Also, in accordance with Arbizu, Kantt & Cepeda (2020), it is crucial not to hide emotions when facing the death of a loved one, as they will serve as a model for children in emotional learning. Finally, it is essential to consider that a child's cognitive level and experience are limited, making it easier for them to draw erroneous conclusions if they are not provided with clear and accurate information, or if they are not allowed to ask questions (Ortego, n.d.). Therefore, it is important to provide the child with truthful and age-appropriate information, as well as allowing them to ask questions, clarifying their doubts, mistakes, and fears. According to Ortego (n.d.), sometimes, as a result of loss, children may fear other losses, and that anxiety can lead to behaviors that are difficult to understand, such as being very anxious in any situation requiring separation from their caregivers. Differences in Childhood Grief versus Grief in Adults The grieving process for the loss of a loved one holds diverse meanings for both adults and children, depending on the situation and the age at which the individual faces such circumstances (Betancur, n.d.). However, a child's experience of grief is distinct from that of an adult (Arbizu, Kantt & Cepeda, 2020). The experiences of loss and grief have a more significant impact on children, as they affect a being still in development, whose defenses, cognitive abilities, emotional support, and coping strategies are still in the process of formation (Arbizu, Kantt & Cepeda, 2020). While grief in adults generally follows a series of stages that vary only in relation to the emotional closeness to the departed, children's grief involves two variables: one related to the direct relationship with the caregiver and another related to how they perceive reality based on chronological age (Betancur, n.d.). Therefore, according to Betancur (n.d.), childhood grief involves a more deeply rooted dependency relationship between the child and the deceased adult. The familial relationship is crucial in terms of the difficulty of grief and coping stages for both children and adults (Betancur, n.d.). It is particularly pertinent to childhood grief since the process in children is directly linked to their perception of death, making it essential to identify their understanding of death given their intellectual capacity. In addition to emotional and psychological development aspects, the level of dependency of the child becomes a key factor, as the child's dependence on the adult in the early stages is fundamental. Consequently, it is of vital importance to review the relationships established after the grieving process with other individuals and environments. According to Betancur (n.d.), under conditions that hinder the overcoming of grief, children generally employ a series of denial mechanisms that allow them to enjoy pleasant situations more easily than adults. Arbizu, J., Kantt, M., & Cepeda, C. (2020). Los niños y niñas frente a la muerte y el duelo. Revistas.unc.edu.ar. Recuperado 3 October 2021, a partir de https://revistas.unc.edu.ar/index.php/aifp/article/view/31686/32523 Betancur, M. EL DUELO INFANTIL POR LA PÉRDIDA DE UN SER QUERIDO Y LAS DIFERENCIAS CON EL DUELO DEL ADULTO. Repositorio.ucp.edu.co. Recuperado 3 October 2021, a partir de https://repositorio.ucp.edu.co/bitstream/10785/4876/1/DDEPCEPNA79.pdf Otego, M., López, S., Álvarez, M., & Aparicio, M. El Duelo. Ocw.unican.es. Recuperado 3 October 2021, a partir de https://ocw.unican.es/pluginfile.php/1575/course/section/2034/tema-11.pdf Sánchez, I. (2013). LA VINCULACIÓN AFECTIVA Y EL CAMINO DE LA VIDA. APEGO, PÉRDIDA Y PSICOPATOLO GÍA INFANTIL. Psiquiatria.com. Recuperado 5 October 2021, a partir de https://psiquiatria.com/trabajos/usr_555289354.pdf Taberno, C. (2019). El duelo en la infancia: un proceso que necesita comprensión. La Mente es Maravillosa. Recuperado 3 October 2021, a partir de https://lamenteesmaravillosa.com/el-duelo-en-la-infancia-un-proceso-que-necesita-comprension/

Cells are the smallest units of life and the fundamental components that define living organisms (Corbin, 2017). Due to their extremely small size, they could not be discovered until the invention of the microscope. It was in the 19th and 20th centuries when the cell theory was developed, explaining that cells are the structural units of living beings and stating that all living organisms are composed of one or more cells. They are also considered functional units, as they perform all vital functions (nutrition, relationship, and reproduction). Likewise, cells are genetic units, containing hereditary material, and all originate from another preexisting cell. According to Corbin (2017), prokaryotic and eukaryotic cells are the two main types of cellular life forms, with their division rooted in the trunk of the biological evolution tree. Cell Classification: Prokaryotes and Eukaryotes Cells are the structural, functional, and genetic units of all living organisms and can be classified in different ways (Corbin, 2017). Among the main classifications are prokaryotic cells (or prokaryotes) and eukaryotic cells (or eukaryotes). Within eukaryotic cells, one can distinguish between animal and plant cells, as well as those of other eukaryotic organisms such as protozoa, algae, and fungi. The two major groups of cells (prokaryotes and eukaryotes) have similarities and differences. Prokaryotic cells are unicellular organisms that lack a defined cellular nucleus, and the DNA (deoxyribonucleic acid) is dispersed throughout the cytoplasm. According to Corbin (2017), eukaryotic cells are organisms composed of cells that possess a true nucleus, enclosed within a double lipid layer, and with organized cytoplasm. Cells in Contrast: Eukaryotic and Prokaryotic Origin An important difference between prokaryotic and eukaryotic cells lies in the timing of their appearance (Corbin, 2017). Naturally, the first cells were relatively simple, adopting the characteristics of prokaryotic cells. According to Corbin (2017), prokaryotic cells are estimated to have originated approximately 3.7 billion years ago, while eukaryotic cells appeared around 2 billion years ago. Size and Shape In general, eukaryotic cells are larger, exceeding 10 micrometers, and exhibit greater complexity compared to prokaryotic cells, which do not exceed 10 micrometers and have a simpler structure (Fernández Roldán, 2023). According to Fernández Roldán (2023), eukaryotic cells can take on various shapes, while prokaryotic cells tend to have a rod or spiral spherical shape. Cellular Organization In correspondence with Corbin (2017), prokaryotic cells tend to give rise to unicellular organisms, while eukaryotic cells are responsible for the formation of multicellular organisms, with the genome allowing the emergence of various specialized cells for different biological functions within a living organism. Nucleus A fundamental distinction between eukaryotic and prokaryotic cells is related to the cell nucleus, where the cell's DNA is located (Fernández Roldán, 2023). Eukaryotic cells exhibit a clearly defined and easily identifiable nucleus, while prokaryotic cells lack this distinctive feature (Corbin, 2017). According to Corbin (2017), genetic information is stored within the nucleus in eukaryotic cells, whereas in prokaryotes, the genetic material is dispersed throughout the cell's interior, indicating a more primitive and less evolved nature. Chromosomes The number of chromosomes is a feature that differentiates the two types of cells: prokaryotic and eukaryotic (Corbin). Corbin (2017) mentions that while prokaryotic cells have a single circular chromosome that houses all their genetic information, eukaryotic cells have multiple linear chromosomes distributed in different regions of the cell nucleus, containing different segments of genetic information. Genetic Material Regarding the configuration of genetic material, it is observed that in eukaryotic cells, genetic material is stored in the nucleus (Corbin, 2017). On the other hand, in prokaryotic cells, DNA is dispersed in the cytoplasm. According to Corbin (2017), it is crucial to highlight that in prokaryotic cells, DNA molecules do not associate with histones, which are proteins responsible for the compact structure of genetic material in nucleosomes. In terms of the shape of genetic material, in prokaryotic cells, genetic information consists of a single circular DNA molecule associated with very few proteins (Brunetti, 2023). Inside the cell, DNA is compacted into a structure called the nucleoid. However, in eukaryotic cells, DNA is organized much more complexly. Genetic material is located in chromosomes, which are composed of a proportional amount of proteins and DNA. Chromosomes are packaged, separated during cell division, transmitted to descendant cells, and transcribed into RNA (ribonucleic acid), which is involved in protein synthesis (Brunetti, 2023). Additionally, according to Corbin (2017), the genetic material of eukaryotic cells is linear and associates with special proteins known as histones. Cell Membrane On one hand, in eukaryotic cells, it is observed that cell membranes contain sterols and are composed of phospholipids (Corbin, 2017; Brunetti, 2023). On the other hand, in the case of prokaryotic cells, only mycoplasmas have a cell membrane (Corbin, 2017). In these cells, according to Brunetti (2023), this cell membrane is mainly composed of peptidoglycan or murein. Organelles In prokaryotic cells, there is an inner matrix with non-membranous organelles (Corbin, 2017). On the other hand, eukaryotic cells present membranous organelles in the cytoplasm, such as the Golgi apparatus (Corbin, 2017). Moreover, in the cytoplasm of eukaryotic cells, there are several non-membranous structures involved in movement, cell contraction, and the establishment and support of cellular architecture (Brunetti, 2023). These structures are different from those present in prokaryotic cells. That is, the cytoskeleton varies between prokaryotic and eukaryotic cells. While eukaryotic cells have microfilaments, intermediate filaments, and microtubules, in prokaryotic cells, the cytoskeleton is formed by two proteins that seem to be precursors to the proteins in eukaryotic cells. The main difference, according to Brunetti (2023), is that these proteins in prokaryotic cells do not cluster to form microtubules in the cytoskeleton. Reproduction Another fundamental distinction between eukaryotic and prokaryotic cells is in relation to reproduction (Fernández Roldán, 2023). In prokaryotic cells, reproduction takes place through the process of binary fission as a method of asexual reproduction (Corbin, 2017). On the contrary, according to Corbin (2017), in eukaryotic cells, reproduction occurs through mitosis and meiosis. Types of Living Organisms They Give Rise To The lifestyle as independent unicellular organisms is characteristic of prokaryotic cells (Fernández Roldán, 2023). Within eukaryotic cells, some live in a unicellular and free form, while others constitute complex multicellular organisms (Fernández Roldán, 2023). According to Corbin (2017), bacteria represent the group of prokaryotic cells, while eukaryotic cells are divided into animals, plants, fungi, protozoa, and algae. Beyond the Differences Prokaryotic cells and eukaryotic cells, although different in many aspects, also exhibit certain similarities (Corbin, 2017). Both are the basic and fundamental units of life on Earth, and thanks to them, different unicellular and multicellular organisms have been able to evolve and colonize various habitats on the planet (Fernández Roldán, 2023). According to Fernández Roldán (2023), both are characterized as membrane-bound structures that preserve their DNA or genetic information inside, along with different enzymatic machinery that enables them to carry out essential functions of nutrition, growth, and reproduction. Their basic chemical structures are similar, as they are composed of carbohydrates, proteins, nucleic acid, minerals, fats, and vitamins (Corbin, 2017). Additionally, both prokaryotic and eukaryotic cells contain ribosomes (which produce proteins), regulate the flow of nutrients and waste entering and leaving the cells, reproduce (though in different ways), require energy to survive, contain cytoplasm inside, and have a cytoskeleton (Corbin, 2017). Finally, in accordance with Corbin (2017), both cell types have a lipid bilayer known as the plasma membrane, which forms the boundary between the inner and outer sides of the cell. References Brunetti, A. (2023, enero 29). Diferencias Entre la Célula Eucariota y Procariota. Ciencia y Biología. https://cienciaybiologia.com/diferencias-celula-eucariota-procariota/ Fernández Roldán, L. (2023, mayo 18). Diferencia Entre Célula Eucariota y Procariota. Ecologia Verde. https://www.ecologiaverde.com/diferencia-entre-celula-eucariota-y-procariota-2550.html Páez, J. C. (2021, marzo 1). Partes de la Célula Animal. Ecología Verde. https://www.ecologiaverde.com/partes-de-la-celula-animal-3279.html Corbin, J. A. (2017, septiembre 1). Las 12 Diferencias Entre Célula Eucariota y Célula Procariota. Psicología y Mente. https://psicologiaymente.com/cultura/diferencias-celula-eucariota-procariota

In the early 16th century, when the majority of people believed that the Earth was the center of the universe, the Polish scientist Nicolaus Copernicus proposed that the planets orbited around the Sun (Redd, 2018). However, his significance lies not only in being the first to formulate a coherent heliocentric theory but also in being the precursor to the scientific revolution that accompanied the European Renaissance (Fernández & Tamaro, 2004). This revolution, involving figures like Galileo Galilei and culminating in the work of Isaac Newton, systematized physics and brought about a profound change in philosophy and religious beliefs. Therefore, this historical process is called the Copernican revolution, which had a significant impact not only on astronomy and science but also on thought and culture (Fernández & Tamaro, 2004). Thus, according to Williams (2015), the Copernican revolution marked the beginning of the era of modern science. Biography Nicolas Copernicus was born on February 19, 1473, in Torun, a city in Thorn, located in central-northern Poland, on the banks of the Vistula River and south of the important Baltic Sea port of Gdańsk (Westman, 2021). He came from an affluent and distinguished family of merchants: his father, Nicolaus, and his mother, Barbara Watzenrode, were part of this guild (Westman, 2021). He was the youngest of four siblings: Andreas, Barbara, and Katharina (Brown, n.d.). His elder brother devoted himself to religious life as an Augustinian canon, similar to his sister Barbara, who became a Benedictine nun and prioress of a convent (Williams, 2015). Only his sister Katharina married and had descendants, whom Nicolas Copernicus cared for until the end of his days. According to Williams (2015), Copernicus never married or had children, dedicating his life to study and the Church. When his father died in 1483, his maternal uncle, Lucas Watzenrode, took charge of his guardianship and education (Westman, 2021). Lucas Watzenrode was a successful clergyman who promoted his nephew's ecclesiastical career and sent him to the best schools of the time (Rabin, 2019). Williams (2015) mentions that although there is little information about his childhood, it is believed that he first attended the School of St. John in Torun, where his uncle had been a teacher, and later the Cathedral School of Wloclawek, which prepared him for admission to the University of Krakow, the alma mater of Lucas Watzenrode. In 1491, Nicolas Copernicus began his studies in the Department of Arts at the University of Krakow, where he specialized in mathematics, astronomy, philosophy, and natural sciences (Williams, 2015). Although there is no record of him obtaining a degree, it was not necessary for his ecclesiastical career or further studies (Rabin, 2019). It was during this time that Copernicus developed his interest in astronomy, thanks to contact with various contemporary philosophers teaching or associated with the School of Mathematics and Astrology in Krakow (Williams, 2015). Additionally, according to Williams (2015), he acquired a solid foundation in mathematical-astronomical knowledge, as well as the works of Aristotle, Euclid, and other humanist writers. In 1495, his maternal uncle and guardian chose him as a canon of the chapter of Frombork of the Cathedral Chapter of Warmia, an administrative position just below that of bishop (Rabin, 2019). Two years later, he assumed the position, securing his financial situation for life. Meanwhile, he moved to the University of Bologna in 1496 to study canon law. There, he lived with astronomy professor Domenico Maria Novara and made his first astronomical observations (Rabin, 2019). Over time, he began to question the Aristotelian and Ptolemaic models of the universe, which had difficulties explaining the motion of planets and their variations in size in the night sky (Williams, 2015). Therefore, according to Williams (2015), he used his time at the university to study Greek and Latin authors, as well as historical information fragments held by the university about ancient astronomical, cosmological, and calendar systems, including other heliocentric theories. In 1501, Nicolas Copernicus moved to Padua, where he studied medicine as part of his ecclesiastical career (Williams, 2015). Like in Bologna, Copernicus completed his designated studies but remained committed to his own astronomical research. Between 1501 and 1503, according to Williams (2015), he continued studying ancient Greek texts, and it is believed that during this time, his ideas for a new astronomy system crystallized, one in which the Earth itself moved. In 1503, after obtaining a doctorate in canon law, he returned to Warmia (Williams, 2015). Around 1507, he first described the heliocentric astronomical system, in which the Earth orbited the Sun, in contrast to the traditional Ptolemaic system, which placed Earth at the center of all celestial movements (Fernández & Tamaro, 2004). According to Fernández & Tamaro (2004), a limited number of manuscript copies of the scheme circulated among astronomers, and Copernicus began to be considered a notable astronomer; however, his research was primarily based on the analysis of texts and data established by his predecessors, as there is little evidence that he made more than fifty observations throughout his life. In 1513, he was invited to participate in the reform of the Julian calendar, and in 1533, his doctrines were presented to Pope Clement VII (Fernández & Tamaro, 2004). In 1536, Cardinal Schönberg wrote to him from Rome, urging him to make his findings public. By then, Copernicus had already finished writing his work "On the Revolutions of the Celestial Spheres," an astronomical treatise advocating the heliocentric theory. According to Fernández & Tamaro (2004), the writing adhered to the model of Ptolemy's "Almagest," preserving the traditional concept of a limited and spherical universe and the principle that circular movements were the only ones suitable for the nature of celestial bodies. However, it contradicted the old conception of the universe, where the center was no longer coincident with that of the Earth, and there was no single common center for all celestial movements. Aware of the novelty of his ideas and fearful of potential criticism, Copernicus did not release the work to the media (Fernández & Tamaro, 2004). However, its publication occurred thanks to the intervention of the astronomer Georg Joachim von Lauchen, known as Rheticus, who visited Copernicus and persuaded him to print the treatise, taking care of it himself. According to Fernández & Tamaro (2004), the work appeared a few weeks before its creator's death, preceded by an anonymous prologue written by editor Andreas Osiander, presenting the Copernican system as a conjecture, as a precautionary measure and in opposition to Copernicus's conviction. Towards the end of 1542, Nicolas Copernicus suffered a cerebral hemorrhage or stroke that left him paralyzed (Williams, 2015). On May 24, 1543, he passed away at the age of 70 and was buried in the cathedral of Frombork, Poland (Williams, 2015). According to Williams (2015), it is said that on the day of his death, he was given an early copy of his book, at which he smiled before dying. The Heliocentric Theory The science of the Renaissance (15th-17th centuries) was propelled by the heliocentric model of Nicolaus Copernicus, who challenged the geocentric conception of the universe that had prevailed for fourteen centuries (Fernández & Tamaro, 2004). This conception, based on Ptolemy's Almagest (2nd century), consisted of a detailed and systematic development of the Greek astronomical method, positing a geocentric cosmos with the Moon, the Sun, and the planets fixed in spheres orbiting the Earth (Fernández & Tamaro, 2004). According to Cartwright (2020), Copernicus's proposal, surprising to the European academic community and especially to the Catholic Church hierarchy, was that the central point of the universe was not the Earth with all other bodies revolving around it, but the Sun, around which the Earth orbited as just another planet. Moreover, the movement of celestial bodies through the sky in a single night and over the course of a year was attributed to the Earth rotating on its own axis and orbiting around the Sun, not to these bodies revolving around the Earth (Cartwright, 2020). Additionally, Copernicus suggested that the Earth completed one rotation on its axis in a day and took a year to orbit around the Sun (Cartwright, 2020). However, the Copernican universe maintained the finitude and limitation of the sphere of fixed stars from classical astronomy (Fernández & Tamaro, 2004). Although Copernicus began to undermine Ptolemy's astronomical work, his goal was rather modest, aiming for a simplification of the traditional system that had become too complex. Therefore, according to Fernández & Tamaro (2004), he assumed that the heliocentric theory would resolve many difficulties and make the system more economical by merely replacing the Earth with the Sun as the center of the universe, without altering the rest of the scheme. Nicolaus Copernicus was the first to develop a coherent heliocentric system, but his theory was not so much based on the observation of empirical data as on the formulation of new hypotheses from a previous worldview with a metaphysical foundation (Fernández & Tamaro, 2004). Firstly, Copernicus was inspired by the Neoplatonic tradition of Pythagorean origin, assigning the Sun an immobile position at the center of the cosmos. Secondly, the Copernican motion of the planets was grounded in a geometric imperative. That is, Copernicus still believed that the planets described uniform circular orbits as they moved around the Sun. Finally, according to Fernández & Tamaro (2004), the Copernican metaphysical paradigm rested on the conviction that the ontological truth of his system perfectly reflected the true harmony of the universe. The Copernican Revolution The Danish Tycho Brahe proposed a third way that combined the Ptolemaic and Copernican systems after the latter presented his heliocentric model in the 16th century (Fernández & Tamaro, 2004). According to this model, planets revolved around the Sun, and the Sun, in turn, revolved around the Earth, thus maintaining the central role of the Earth in the universe (Fernández & Tamaro, 2004). However, Brahe did not adopt a heliocentric cosmology; instead, he left his observational data to Johannes Kepler, a German astronomer who used them to enhance the heliocentric model by introducing elliptical orbits in the year 1609 (Williams, 2015). By the end of the same century, according to Fernández & Tamaro (2004), Isaac Newton published the "Mathematical Principles of Natural Philosophy" with his three axioms or laws of motion and the law of universal gravitation. The Copernican heliocentrism had laid the foundation for traditional physics, providing a comprehensive description of terrestrial and celestial phenomena. However, Copernicus's contribution's importance goes beyond a more or less successful contribution to astronomical science (Fernández & Tamaro, 2004). By equating the Earth with the other planets orbiting the Sun, Copernicus's cosmos composition broke with scholastic and philosophical postulates that advocated the distinction between an immutable celestial world and a sublunary world subject to changes and movements (Fernández & Tamaro, 2004). Over time, this theory became widespread, accepted, and gained the support of many influential proponents (Williams, 2015). Thus, Copernicus's theses marked the first step in the progressive secularization of Renaissance conceptions, which began to seek an interpretation of interactions between the universe, Earth, and human beings. According to Fernández & Tamaro (2004), the first gap between science and magic, astronomy and astrology, mathematics and mystical numbers opened up. The new system had profound repercussions on scientific methodology, mindset, and the religious and philosophical convictions of an entire era (Fernández & Tamaro, 2004). Consequently, in line with Fernández & Tamaro (2004), five centuries later, the language continues to use the concept of the "Copernican revolution" to denote a drastic change in a situation or way of thinking. References Brown, C. (s.f.). Nicolaus Copernicus. Khan Academy. Recuperado 17 de noviembre de 2021, de https://www.khanacademy.org/humanities/big-history-project/big-bang/how-did-big-bang-change/a/nicolaus-copernicus-bh Cartwright, M. (2020). Nicolaus Copernicus. World History Encyclopedia. Recuperado 17 de noviembre de 2021, de https://www.worldhistory.org/Nicolaus_Copernicus/ Fernández, T., & Tamaro, E. (2004). Biografia de Nicolás Copérnico. Biografías y Vidas. Recuperado 17 de noviembre de 2021, de https://www.biografiasyvidas.com/biografia/c/copernico.htm Rabin, S. (2019). Nicolaus Copernicus. Stanford Encyclopedia of Philosophy. Recuperado 17 de noviembre de 2021, de https://plato.stanford.edu/entries/copernicus/ Redd, N. T. (2018). Nicolaus Copernicus biography: Facts & discoveries. Space.com. Recuperado 17 de noviembre de 2021, de https://www.space.com/15684-nicolaus-copernicus.htmlhttps://www.space.com/15684-nicolaus-copernicus.html Westman, R. (2021). Nicolaus Copernicus. Encyclopedia Britannica. Recuperado 17 de noviembre de 2021, de https://www.britannica.com/biography/Nicolaus-Copernicus Williams, M. (2015). Who Was Nicolaus Copernicus? Universe Today. Recuperado 17 de noviembre de 2021, de https://www.universetoday.com/45091/copernicus/

Cells represent the smallest anatomical unit of organisms and perform various functions, which are grouped into three fundamental actions: nutrition, interaction, and reproduction (Montagud Rubio, 2020). In order to carry out these processes, Montagud Rubio (2020) mentions that it is observed that cells have organelles and other structures that facilitate their interaction with the environment, supplying energy to the organism and generating waste during this process. What is a Cell? The cell is the smallest anatomical unit that constitutes the structure of living beings (Montagud Rubio, 2020). Although the size of cells may vary, on average, they measure around 10 µm (micrometers) (Álvarez, 2023). The vast majority of these cells are microscopic, implying that they can only be seen through the use of a microscope. However, according to Álvarez (2023), there is an exception: the human egg, which, with its 100 µm size, can be observed with the naked eye and is comparable in magnitude to the tip of a pencil. The fundamental areas of all cells are the nucleus, the plasma membrane, and the cytoplasm, all housing various organelles (Montagud Rubio, 2020). Thanks to the presence of these organelles, cells can carry out the three essential functions that categorize them as living beings: nutrition, interaction, and reproduction. In correspondence with Montagud Rubio (2020), these functions are achieved through specific biochemical processes that enable cell survival and functioning. Types of Cells The most relevant classification of cells is based on whether they have a cellular nucleus or not (Montagud Rubio, 2020). Prokaryotic cells exhibit a simple basic structure without a nuclear membrane, causing their genetic material to be dispersed in an area called the nucleoid, directly connected to the rest of the cytoplasm (Álvarez, 2023). With dimensions ranging from 1 to 5 µm, these cells are small. According to Álvarez (2023), they are recognized as the original forms of life on Earth, and to the best of our knowledge, all organisms formed by prokaryotic cells are unicellular. In contrast, eukaryotic cells have a more complex structure (Álvarez, 2023). Their nucleus is surrounded by a nuclear membrane, confining their genetic material in the nucleus. In addition, these cells house organelles, also known as "organelles," in their cytoplasm, which can be bounded by membranes. Their size varies between 10 - 100 µm, being larger than prokaryotic cells. In the terrestrial evolution, eukaryotic cells emerged after prokaryotic cells (Álvarez, 2023). Although the differentiation between eukaryotes and prokaryotes is important, especially in the study of species evolution, the eukaryotic cell has been the most studied, with two types identified: animal and plant cells, differing in their shape and organelles (Montagud Rubio, 2020). According to Montagud Rubio (2020), animal cells are found in animals, while plant cells, besides being present in plants, can also be found in algae. Cell Parts Plasma Membrane The plasma membrane, also known as the "cell membrane" or "plasmalema," delimits the interior of the cell from its surrounding environment (Montagud Rubio, 2020). This structure, with a thickness of approximately 7 nm (nanometers or millionths of a millimeter), stands out for its precise and organized arrangement that covers the entire cell (Patton & Li, 2016). According to Montagud Rubio (2020), its function lies in regulating the entry and exit of substances, facilitating the entry of nutrients, and the excretion of waste. This structure is composed of two layers containing carbohydrates, phospholipids, and proteins, constituting a selectively permeable barrier. This means that, while maintaining the cell's stability and providing shape, it can modify its configuration to allow the entry or exit of substances (Montagud Rubio, 2020). Additionally, cholesterol, an additional lipid molecule, contributes to stabilizing the phospholipid molecules, thus preventing potential breaks in the plasma membrane (Patton & Li, 2016). According to Álvarez (2023), the main functions of this membrane include shaping and stabilizing the cell, establishing a separation between the cell's internal content and its surrounding environment, facilitating the exchange of substances to and from the cell, as well as participating in cellular interactions. Cell Wall This is a characteristic structure of plant cells, such as those present in plants and fungi (Montagud Rubio, 2020). Plant cells exhibit an additional wall outside the plasma membrane, providing them with rigidity and resistance. This wall is mainly composed of cellulose (Montagud Rubio, 2020). However, according to Álvarez (2023), the composition of the cell wall varies depending on the cell type. For example, in plants, it is mostly composed of cellulose, while in bacteria, it is constituted by peptidoglycan, a copolymer of sugars and amino acids. Nucleus The nucleus is the structure that allows the distinction between eukaryotic cells, which possess it, and prokaryotic cells, which lack it (Montagud Rubio, 2020). When observed under the microscope, the nucleus appears as a simple structure: a small sphere in the center of the cell (Patton & Li, 2016). Its main function lies in safeguarding the genetic material, which is organized into DNA chains forming genes that encode different proteins (Montagud Rubio, 2020). These genes, in turn, are grouped into chromosomes (Montagud Rubio, 2020). In addition to this protective function, Montagud Rubio (2020) and Patton & Li (2016) mention that the nucleus plays fundamental roles, such as the generation and reassembly of messenger RNA (mRNA) into proteins, the formation of pre-ribosomes (rRNA), the organization of genes into chromosomes for cell division, and the regulation of the complex process of cell reproduction. The cell nucleus is surrounded by a nuclear membrane composed of two separate layers (Patton & Li, 2016). This envelope has extremely small nuclear pores that facilitate the entry and exit of large molecules from the nucleus. According to Patton & Li (2016), within the nucleus, there is the nucleoplasm, a special cellular substance that houses crucial structures, such as the nucleolus and chromatin granules. Nuclear Membrane The structure in question, like the plasma membrane that surrounds the cell, is characterized by being a double lipid membrane envelope around the nucleus (Montagud Rubio, 2020). According to Montagud Rubio (2020), this nuclear membrane plays a crucial role in regulating communication between the inside of the nucleus and the cytoplasm. Nucleolus Within the cell nucleus is a structure whose main function lies in the synthesis of ribosomes, from its DNA components, to generate ribosomal RNA (rRNA) (Montagud Rubio, 2020). In accordance with Montagud Rubio (2020), this activity is linked to protein synthesis. For this reason, in cells with a high rate of protein synthesis, a greater number of these nucleoli is commonly found. Chromosomes Structures containing genetic material are known as chromosomes, particularly visible during the process of cell division (Montagud Rubio, 2020). Humans have 22 pairs of numbered chromosomes (autosomes) and one pair of sex chromosomes (XX or XY), totaling 46 (Bates, 2024). According to Montagud Rubio (2020), each pair contains two chromosomes, one from each parent, meaning that children inherit half of their chromosomes from their mother and the other half from their father. Chromatin Chromatin, composed of DNA and a variety of proteins, including histones and non-histones, resides in the cell nucleus, constituting the cell's genetic material (Montagud Rubio, 2020). According to Montagud Rubio (2020), nucleosomes, identified as the fundamental units of information, are an integral part of this complex system. Cytoplasm The cytoplasm is recognized as the interior medium of the cell, often referred to as its body (Montagud Rubio, 2020). It consists of a liquid part known as "cytosol," which is composed of water, ions, and proteins (Álvarez, 2023). Within the cytosol, all cellular organelles are immersed (Álvarez, 2023). Many vital chemical processes for life take place in this environment (Montagud Rubio, 2020). The cytoplasm can be divided into two sections. One of them, the ectoplasm, has a gelatinous consistency, while the other, the endoplasm, is more fluid and serves as the site where organelles reside. According to Montagud Rubio (2020), this characterization is associated with the main function of the cytoplasm, which is to facilitate the movement of cellular organelles and provide them with protection. Cytoskeleton The cytoskeleton presents itself as an internal skeleton within the cell, providing cohesion and structure (Montagud Rubio, 2020). The cytoskeleton is composed of three types of filaments: microfilaments, intermediate filaments, and microtubules (Montagud Rubio, 2020). Microfilaments consist of fibers formed by very thin proteins, with a diameter between 3 and 6 nanometers. Actin, a contractile protein, is the main component of these microfilaments. On the other hand, intermediate filaments, approximately 10 nanometers, provide tensile strength to the cell. According to Montagud Rubio (2020), microtubules are cylindrical tubes with a diameter of 20 to 25 nanometers, composed of tubulin units, and act as the scaffold shaping the cell. Types of Organelles According to their designation, organelles are small organs present inside the cell (Montagud Rubio, 2020). Montagud Rubio (2020) mentions that, from a technical standpoint, the plasma membrane, cell wall, cytoplasm, and nucleus are not classified as organelles, although there could be a debate regarding whether the nucleus should be considered as such or if it is a structure that requires a representative classification. Mitochondria Mitochondria are organelles present in eukaryotic cells, providing the necessary energy for various activities (Montagud Rubio, 2020). In comparison to other organelles, they are considerably larger and have a globular shape. Their main function is to break down nutrients and synthesize adenosine triphosphate (ATP), a crucial substance for energy acquisition. In addition to their energy function, they exhibit reproductive capacity by possessing their own DNA, allowing them to generate more mitochondria as per the cell's needs (Montagud Rubio, 2020). The number of mitochondria in a cell can vary significantly, reaching up to thousands, depending on cellular activity (Álvarez, 2023). According to Montagud Rubio (2020), the production of ATP occurs during cellular respiration, where mitochondria use molecules from carbohydrate-rich foods to produce this vital substance. Golgi Apparatus The Golgi apparatus, present in all eukaryotic cells, plays an essential role in the production and transport of proteins, lipids, and lysosomes within the cell (Montagud Rubio, 2020). Its main function can be likened to a packaging plant, as it modifies vesicles originating in the endoplasmic reticulum. According to Montagud Rubio (2020), this system of endomembranes folds upon itself, creating a structure similar to a curved labyrinth, organized into flattened sacs or cisterns. Lysosomes Lysosomes, present in eukaryotic animal cells, are vesicles surrounded by a membrane, originating from the Golgi apparatus (Álvarez, 2023). These vesicles contain digestive and hydrolytic enzymes, which accelerate the hydrolysis of chemical bonds in various molecules. In addition to this capacity, lysosomes can carry out the digestion of other organelles within the cell, returning their components to the cytosol for subsequent reuse by the cell (a process called "autophagy"). They can also perform the complete digestion of a cell (a process called "autolysis"). When the components to be digested come from outside the cell, the process is referred to as "heterophagy" (Álvarez, 2023). According to Montagud Rubio (2020), these spherical structures are surrounded by a single membrane. Vacuole Plant eukaryotic cells and some animal cells contain vacuoles (Álvarez, 2023). They can also be found in some prokaryotic cells (Álvarez, 2023). These compartments, enclosed by the plasma membrane, house various fluids, water, enzymes, and can contain solids such as sugars, proteins, salts, and other nutrients (Montagud Rubio, 2020). The majority of vacuoles originate from the fusion of membranous vesicles. Their structure has no defined shape and varies according to cellular needs (Montagud Rubio, 2020). In accordance with Álvarez (2023), the main function of vacuoles is the storage of water, molecules, and nutrients. Chloroplasts Chloroplasts are found in eukaryotic plant cells and green algae (Álvarez, 2023). This cellular organelle consists of two membranes that house vesicles, chlorophyll, and thylakoids inside. The thylakoids are where the reaction that absorbs photons from sunlight to carry out photosynthesis takes place. Although chloroplasts are exclusive to plant and algae cells, there is a significant exception. The mollusk known as the Eastern Emerald Elysia, scientifically identified as Elysia chlorotica, feeds on chloroplasts present in the Vaucheria litorea algae. Surprisingly, according to Álvarez (2023), this mollusk is capable of photosynthesis by using the algal chloroplasts as an energy source. Ribosomes Ribosomes are organelles responsible for protein synthesis, an essential process for cell growth and reproduction (Montagud Rubio, 2020). They are present in both eukaryotic and prokaryotic cells but have some differences in structure and location (Álvarez, 2023). In eukaryotic cells, they are made up of two subunits that are formed separately in the nucleolus and join in the cytoplasm to synthesize proteins. Additionally, in these cells, they can be located in the nuclear membrane, the rough endoplasmic reticulum, the cytosol, mitochondria, and chloroplasts (in the case of plants). In prokaryotic cells, they are scattered throughout the cytoplasm and are smaller than those in eukaryotic cells (Álvarez, 2023). According to Montagud Rubio (2020), they are responsible for translating genetic information obtained from DNA into RNA, which is the code determining the amino acid sequence of proteins. Endoplasmic Reticulum The endoplasmic reticulum is a system of channels present in eukaryotic cells that is responsible for transferring or synthesizing lipids and proteins (Montagud Rubio, 2020; Álvarez, 2023). This system is distributed throughout the cytoplasm and is involved in protein synthesis (Montagud Rubio, 2020). The membranes of the endoplasmic reticulum continue with the nuclear envelope and can extend close to the plasma membrane (Montagud Rubio, 2020). There are two types of endoplasmic reticulum: rough and smooth (Montagud Rubio, 2020; Álvarez, 2023). The rough endoplasmic reticulum is a structure located below the nuclear membrane, and its surface is covered with ribosomes, organelles responsible for protein synthesis (Álvarez, 2023). On the other hand, according to Álvarez (2023), the smooth endoplasmic reticulum is a structure that extends from the rough endoplasmic reticulum, and its surface does not contain ribosomes, so proteins are not synthesized in its structure, but fatty acids and steroids are synthesized. Cilia Prokaryotic and eukaryotic animal cells and some algae contain extensions of the plasma membrane similar to hairs, known as cilia (Álvarez, 2023). According to Álvarez (2023), their main function is to perform movements similar to those of an oar, contributing to the movement of the surrounding fluid to the cell. Centrosome The centrosome is found in animal eukaryotic cells (Álvarez, 2023). This organelle is composed of centrioles and pericentriolar material, which is a set of proteins that surrounds the centrioles. According to Álvarez (2023), these tubulin complexes act as organizing centers for the growth of the mitotic spindle, which is the set of microtubules involved in cell division. Centriole The centriole is a cylindrical organelle composed of microtubules (Montagud Rubio, 2020). It is part of the cytoskeleton and contributes to maintaining cell shape, as well as transporting organelles and particles within the cell. When two centrioles are positioned together perpendicularly inside the cell, they are called a diplosome. This structure plays a crucial role in the movement of cilia and flagella in unicellular organisms. Additionally, according to Montagud Rubio (2020), centrioles actively participate in cell division, with each contributing to the formation of centrioles in daughter cells. Flagella Flagella are found in prokaryotic and eukaryotic animal cells, as well as in some algae (Álvarez, 2023). Their structure is similar to that of cilia but distinguishes itself by being longer. These flagella initiate the movement of cells as a whole, acting as small propellers that provide them with mobility (Álvarez, 2023). In accordance with Montagud Rubio (2020), this characteristic is typical of unicellular organisms or specialized cells, such as sperm cells. Differences Between Animal and Plant Cells Animal cells and plant cells share numerous organelles and similar structures, but they also exhibit certain details that allow for their distinction (Montagud Rubio, 2020). One of the most notable aspects is the presence of the plant cell wall, which surrounds the plasma membrane, giving it a hexagonal shape and a rigid structure. Additionally, chloroplasts stand out as a structure exclusively found in plant cells. These organelles house chlorophyll, crucial during photosynthesis. They are responsible for synthesizing sugars from carbon dioxide, water, and sunlight. Consequently, according to Montagud Rubio (2020), organisms with plant cells are classified as autotrophs since they can manufacture their own food, unlike those with animal cells, lacking chloroplasts and thus being heterotrophs. In animal cells, energy is exclusively obtained from mitochondria, while in plant cells, both mitochondria and chloroplasts are present (Montagud Rubio, 2020). This arrangement allows plant cells to harness energy from two different organelles. This difference is crucial as plant organisms can perform both photosynthesis and cellular respiration, while animals can only carry out the latter biochemical process. Another detail, though not as relevant as the ability to perform photosynthesis, is the uniqueness of the vacuole in plant cells, which tends to be singular, centrally located, and of considerable size. In contrast, in animal cells, there are several smaller vacuoles. Additionally, according to Montagud Rubio (2020), there is the presence of centrioles in animal cells, a structure absent in plant cells. References Álvarez, D. O. (2023). Célula. Concepto. https://concepto.de/celula-2/ Bates, S. A. (2024). Chromosome. National Human Genome Research Institute. https://www.genome.gov/genetics-glossary/Chromosome Montagud Rubio, N. (2020, marzo 5). Las Partes de la Célula y los Orgánulos más Importantes: Un Resumen. Psicología y Mente. https://psicologiaymente.com/salud/partes-de-celula Patton, K. T., & Li, S. (2016). Anatomía y Estructura de la Célula: Tamaño, Composición y Funciones. En www.elsevier.com (pp. 39–41). Elsevier. https://www.elsevier.com/es-es/connect/anatomia-y-estructura-de-la-celula

Biography Marko Marulić, born on August 18, 1450, in Split, Dalmatia, and died on January 6, 1524, in the same city, was a Croatian philosopher and moralistic poet (Britannica, 2021). His verses in the vernacular marked the beginning of distinctive Croatian literature. Coming from a noble family, Marulić studied classical languages, literature, and philosophy in Padua, Italy, where he also received sacred orders (Fernández & Tamaro, 2004; Britannica, 2021). During his lifetime, he gained European fame with his Latin texts (Fernández & Tamaro, 2004). Later, his works in the Croatian vernacular elevated him to the status of "the father of Croatian literature." However, according to Fernández & Tamaro (2004), some aspects of his biography and works are still subjects of study. According to the tradition of the nobility of his time, he led a life dedicated to public office and study (Fernández & Tamaro, 2004). His didactic moral works, written in Latin and translated into many European languages, emphasized practical Christianity and reflected an appreciation for Stoic thinking (Britannica, 2021). Consequently, he can be considered a multifaceted representative of the Christian Renaissance. Most of his Latin works were widely distributed (Fernández & Tamaro, 2004). According to Fernández & Tamaro (2004), among his notable works are the moral treatise "De Institutione bene vivendi per exempla sanctorum," inspired by the Bible and exerting a strong influence on San Francisco Javier, and "Davidiad," a poem about King David. As he matured, he turned his attention to the cultivation of Croatian letters (Fernández & Tamaro, 2004). In 1501, he wrote his main poem, "Judit," followed by a less significant composition on the biblical theme of chaste Susanna (Fernández & Tamaro, 2004; Britannica, 2021). This work, by elevating the Croatian vernacular to the status of a literary language and combining classical and Italian literary education with Croatian poetic traditions, proved to be a stepping stone for the emerging Croatian literature (Fernández & Tamaro, 2004). In Croatian, he also wrote "A Life of St. Jerome" and translated "The Imitation of Christ." It seems that he also wrote verses in Italian and translated the first canto of Dante's Inferno into Latin. In 1510, at the age of 60, Marulić retired to a Franciscan monastery on the island of Šolta (Britannica, 2021). However, according to Britannica (2021), two years later, he returned to Split, his hometown, disillusioned by his monastery experience. First Use of the Word "Psychology" Coherently translating from Spanish to English: Technical and encyclopedic literature provides different versions of the formation and initial use of the word "psychology." The most important psychological and philosophical dictionaries, textbooks, and encyclopedias worldwide present three main perspectives on the origin of the term, which, as a designation for the scientific or philosophical study of mental life, has broad application. However, a little-known document until now provides information that invites a reconsideration of the established opinion on the first appearance of the word "psychology" in the scientific field. At least 66 years before Gockel, the great humanist Marko Marulić had already used the term (Kristic, 2001). However, according to Luccio (2013), it is difficult to determine with certainty what the humanist from Split meant when coining the term "psichiologia" around the year 1520, as only the title of his work has survived: "Psichiologia de ratione animae Humanae." A brief biography of Marulić, along with a list of his works, was written by his contemporary Franjo Božičević and published posthumously by Daniel Farlatus and, more recently, by Miroslav Marcovich (Luccio, 2013). In the list of works, some authors mention Marulić's treatise "Psychologia" and consider it a "liber primus." As noted by other authors, the term, probably of Byzantine origin, appears in different variations in the available lists of Marulić's works, including "Psicología" and "Etología." However, according to Luccio (2013), the oldest versions indicate that "psichiologia" is probably the variant used by the humanist author. About thirty or forty years ago, various historians of psychology initiated a controversy about the meaning of Marulić's "psichiologia" and its role in the development of the discipline (Luccio, 2013). Some authors hypothesized that by "ratio," the author referred to some kind of mental hygiene, while others insisted that the meaning of "ratio" was that of nature. However, deciding that Marulić's work was a treatise on the nature of the soul doesn't say much, as the 16th century was filled with significant treatises on the soul. What was Marulić's opinion on the most relevant topics? On the methods of researching the soul? On its divisions? What was his position between Aristotelianism and Galenianism? All of this is unknown and has not had a significant impact on the history of ideas. In fact, according to Luccio (2013), it took more than two centuries after Marulić for the term "psychology" to begin to have the meaning attributed to it today in science and philosophy. Referencias Britannica. (2021). Marko Marulić. Encyclopedia Britannica. Recuperado 27 October 2021, a partir de https://www.britannica.com/biography/Marko-Marulic Fernández, T., & Tamaro, E. (2004). Biografia de Marko Marulic. Biografiasyvidas.com. Recuperado 27 October 2021, a partir de https://www.biografiasyvidas.com/biografia/m/marulic.htm Krstic, K. (2001). Classics in the History of Psychology. Psychclassics.yorku.ca. Recuperado 27 October 2021, a partir de https://psychclassics.yorku.ca/Krstic/marulic.htm Luccio, R. (2013). Psychologia – the birth of a new scientific context.

From a biological perspective, a molecule containing an amino group and a carboxyl group in its physical structure is termed an amino acid (Sánchez Amador, 2020). This organic compound serves as the foundation for proteins. When considering the concept of amino acids from a purely physiological standpoint, it may initially seem unexciting; however, the situation becomes fascinating when discovering that proteins constitute the most prevalent molecules throughout the human body, representing 50% of the dry weight of all tissues. These nutrients are distributed throughout all cells, shaping organs, muscles, tissues, hair, and skin. In conjunction with nucleic acids (RNA and DNA), proteins stand as the cornerstone of the life of all living beings. Therefore, according to Sánchez Amador (2020), amino acids play an essential role in the concept of human "existence" and that of all organisms. ¿Qué es un Aminoácido? Paying attention to a functional approach, it could be stated that each of the amino acids contributes to the formation of proteins, which, in turn, integrate into cells and give rise to the complex tissues that make up the human body. These protein structures, fundamental for existence, take the form of polymeric chains formed by amino acids joined by peptide bonds (Sánchez Amador, 2020). The term "amino acid" is derived from the abbreviation of α-amino (alpha-amino) carboxylic acid (Reddy, 2024). Each molecule is composed of a central carbon atom (C), known as the α-carbon, to which both an amino group and a carboxyl group are attached. The remaining two bonds of the α-carbon atom are usually satisfied by a hydrogen atom (H) and the R group. Amino acids show variations in their chemical structure, mainly in the R group. According to Reddy (2024), the general formula for an amino acid is: The Classification and Role of Amino Acids In general terms, it is often assumed that all amino acids play a crucial role as fundamental components of proteins, thus establishing a clear distinction between those considered "essential" and those classified as "non-essential" (Sánchez Amador, 2020). However, according to Sánchez Amador (2020), not all amino acids participate in widely accepted protein complexes. Non-Protein Amino Acids All metabolic intermediates and neurotransmitters have a characteristic amino acid structure but are not linked to the polymeric chain that makes up proteins (Sánchez Amador, 2020). According to Sánchez Amador (2020), examples of these are Ornithine and Citrulline, which function as intermediate compounds in the urea cycle, as well as Homocysteine and Homoserine, essential molecules for various metabolic processes. Worth mentioning is the precursor substrate Dihydroxyphenylalanine (DOPA), which initiates metabolic pathways leading to neurotransmitters such as Dopamine and Adrenaline. Although these compounds play a more discreet role compared to those directly associated with protein polymers, their importance is undeniable. These hormones increase the heart rate of living beings and stimulate fight-or-flight responses, thus theoretically enhancing individual survival. Sánchez Amador (2020) mentions that, even though they are not structural amino acids per se, their function is unquestionable. Protein Amino Acids These are encoded in the genome, meaning their assembly instructions are stored in DNA (Sánchez Amador, 2020). Through processes like transcription and translation, mediated by messenger and transfer RNAs, these synthesis instructions lead to the formation of the desired protein. This formation is based on the concatenation of amino acids in a specific order. Common amino acids for all living beings include Alanine, Arginine, Asparagine, Aspartate, Cysteine, Phenylalanine, Glycine, Glutamate, Glutamine, Histidine, Isoleucine, Leucine, Lysine, Methionine, Proline, Serine, Tyrosine, Threonine, Tryptophan, and Valine. These twenty molecules represent the pillars for life. Given the anthropocentric classification of biological terms, Sánchez Amador (2020) indicates that these canonical amino acids have been categorized as "essential" and "non-essential" based on their consumption necessity. Essential amino acids are those the human body cannot produce on its own and must be consumed in the form of proteins in the diet (Sánchez Amador, 2020). Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, and Valine, in other words, nine of the previously named twenty, are examples of these amino acids. According to Sánchez Amador (2020), it is essential to emphasize that the "essentiality" of these amino acids depends on the species, as not all living organisms follow the same metabolic pathways. Phenylalanine is associated with a sense of well-being as it regulates endorphins (García-Allen, 2017). Among its notable functions are reducing excess appetite and alleviating pain. It is also involved in the synthesis of catecholamines such as Adrenaline, Dopamine, and Noradrenaline, promoting alertness, improving memory and learning, and increasing vitality. According to García-Allen (2017), supplements containing this amino acid can be used to improve symptoms of Parkinson's, vitiligo, chronic pain, or for the comprehensive treatment of depression. A deficiency in Isoleucine seems to be implicated in some mental and physical disorders, such as depression, behavior alterations, and decreased muscle mass, among others (García-Allen, 2017). This amino acid is essential for the formation of hemoglobin and muscle tissue, and it stabilizes and regulates blood sugar and energy levels. Additionally, according to García-Allen (2017), it contributes to wound healing, skin, and bone health. Lysine inhibits the development of viruses in the body and is used in the treatment of herpes and viruses associated with chronic fatigue syndrome (García-Allen, 2017). It participates in the synthesis of L-carnitine along with vitamin C. Moreover, it contributes to collagen formation, the connective tissue present in bones, ligaments, tendons, and joints. It promotes calcium absorption, essential for children as it is crucial for bone formation. According to García-Allen (2017), it also plays a role in hormone production and reduces serum triglyceride levels. Threonine is indispensable for collagen formation and proves to be an essential factor in the antibody production process (García-Allen, 2017). Additionally, according to García-Allen (2017), it is essential for the normal functioning of the gastrointestinal tract and can convert into Glycine, a neurotransmitter in the central nervous system. Tryptophan, an essential amino acid, has caught the attention of psychologists and health professionals due to its crucial role in serotonin and melatonin synthesis (García-Allen, 2017). Consequently, according to García-Allen (2017), it plays a fundamental role in mood regulation and directly contributes to improving sleep quality. Valine competes with tyrosine and tryptophan when crossing the blood-brain barrier (García-Allen, 2017). The higher the valine level, the lower the levels of the other two amino acids in the brain. Valine is actively absorbed and used directly by the muscle as an energy source, so it is not processed by the liver before entering the bloodstream. According to García-Allen (2017), valine deficiency leads to lower absorption of other amino acids (and proteins) by the gastrointestinal tract. Histidine proves beneficial in the treatment of anemia due to its connection with hemoglobin (García-Allen, 2017). Its role as a precursor to histamine has made it a resource used in allergy treatment. Finally, according to García-Allen (2017), this amino acid contributes to maintaining the proper blood pH and has proven useful in the treatment of rheumatoid arthritis. Methionine actively plays a role in fat breakdown, facilitating the reduction of cholesterol in the blood (García-Allen, 2017). Also, its influence is highlighted in preventing disorders in hair, skin, and nails. According to García-Allen (2017), it has antioxidant properties and actively participates in RNA and DNA synthesis. Non-essential amino acids are produced through metabolic pathways included in human physiology (Sánchez Amador, 2020). These include Alanine, Tyrosine, Aspartate, Cysteine, Glutamate, Glutamine, Glycine, Proline, Serine, Asparagine, and Arginine, that is, 11 of the 20 canonical ones. Various metabolic pathways even vary among mammals. For example, Sánchez Amador (2020) mentions that cats lack an essential enzyme to synthesize Taurine, derived from Cysteine, making it essential for them. Arginine plays a fundamental role in normal immune system activity and wound healing (García-Allen, 2017). It also participates in growth hormone release, increases insulin and glucagon release, and is a precursor to Gamma-Aminobutyric Acid (GABA). According to García-Allen (2017), it is also known for reducing tumor size and being necessary for spermatogenesis. Aspartic Acid, an amino acid recognized for its ability to increase endurance and physical performance, is beneficial for combating chronic fatigue (García-Allen, 2017). García-Allen (2017) mentions that, as one of the two main excitatory amino acids, along with Glutamic Acid, Aspartic Acid contributes to protecting the liver, participates in DNA and RNA metabolism, and enhances the immune system. Glutamic Acid, along with Aspartic Acid, stands out as an exciter, sharing numerous functions (García-Allen, 2017). It contributes to improving physical performance and reducing fatigue. According to García-Allen (2017), its role is essential in DNA and RNA synthesis, providing protection to the body and strengthening the immune system. Alanine plays a significant role in muscle growth and serves as a significant energy source for the muscle (García-Allen, 2017). According to García-Allen (2017), its involvement in sugar metabolism, strengthening the immune system through antibody production, and its fundamental role in connective tissue highlight it as a key component for overall health. Asparagine is formed by the combination of Aspartic Acid with adenosine triphosphate (ATP) (García-Allen, 2017). According to García-Allen (2017), this substance plays a crucial role in short-term memory processes, contributes to ammonia removal from the body, reduces fatigue, and actively participates in DNA synthesis. Cysteine is an antioxidant that protects against radiation, pollution, ultraviolet light, and other phenomena that generate free radicals (García-Allen, 2017). It acts as a natural "detoxifier" and is essential for the growth, maintenance, and repair of skin and hair. Additionally, according to García-Allen (2017), it is a precursor to the amino acid Taurine and Chondroitin Sulfate, the latter being the main component of cartilage. Glycine is part of the hemoglobin structure and is one of the two main inhibitory neurotransmitters of the nervous system, the other being Gamma-Aminobutyric Acid (GABA) (García-Allen, 2017). It also participates in the formation of cytochromes, enzymes involved in energy production. According to García-Allen (2017), it contributes to the production of Glucagon, which supports Glycogen metabolism. Glutamine, recognized as a precursor to two significant neurotransmitters of the central nervous system, Glutamate and Gamma-Aminobutyric Acid (GABA), plays a vital role in maintaining normal and constant blood sugar levels, as well as muscle strength and endurance (García-Allen, 2017). Similarly, according to García-Allen (2017), this amino acid is essential for proper gastrointestinal function. Proline, a fundamental component of cartilage, emerges as a crucial element for joint, tendon, and ligament health (García-Allen, 2017). This amino acid contributes to maintaining heart health and stands out as the main precursor of glutamate. García-Allen (2017) mentions that among the notable functions of this amino acid is sustaining skin and joint health. Serine actively participates in enhancing the immune system by contributing to antibody and immunoglobulin production, as well as playing a fundamental role in the development of the myelin sheath (García-Allen, 2017). Also, according to García-Allen (2017), this amino acid is crucial for muscle growth and maintenance. Tyrosine, a precursor amino acid to the hormone thyroxine, participates in metabolic processes (García-Allen, 2017). Additionally, it stands out as a precursor to growth hormone and neurotransmitters such as Dopamine, Norepinephrine, Epinephrine (Adrenaline), and Serotonin. These elements, according to García-Allen (2017), positively influence mood, sleep, clarity of thought, concentration, and memory. The third category corresponds to conditional amino acids (Sánchez Amador, 2020). The question of what an amino acid is carries certain considerations, and one of them highlights the existence of conditional amino acids. These are not essential under normal conditions but may be necessary in illness or special conditions. A clear example of this is arginine, considered non-essential under normal circumstances. However, according to Sánchez Amador (2020), its intake should be monitored in the diet when certain conditions, such as obesity disorders and sickle cell anemia, arise. References García - Allen, J. (2017, abril 12). Tabla de Aminoácidos: Funciones, Tipos y Características. Psicología y Mente. https://psicologiaymente.com/neurociencias/tabla-de-aminoacidos Reddy, M. K. (2024, enero 3). Amino Acid. Enciclopedia Británica. https://www.britannica.com/science/amino-acid Sánchez Amador, S.A. (2020, agosto 20). ¿Qué es un Aminoácido? Características de Este Tipo de Moléculas. Psicología y Mente. https://psicologiaymente.com/salud/que-es-aminoacido

Coherently translate from Spanish to English: Proteins, whose term comes from the Greek "proteios," meaning fundamental or essential, are indispensable elements for the proper development and functioning of the cells that make up the organism (Chuan, 2021). These biomolecules, primarily composed of carbon, hydrogen, oxygen, and nitrogen, may also contain other chemical elements such as sulfur, phosphorus, iron, magnesium, or copper in certain protein structures (Sánchez Amador, 2020). Proteins exhibit great structural and functional diversity and can be classified into different types based on their role in the organism (Chuan, 2021). In line with Chuan (2021), some proteins act as hormones, such as insulin, which regulates blood sugar levels; others function as enzymes, for example, lipases, involved in digestive processes; and others play a defensive role, like antibodies, which combat infections. From a physiological standpoint, proteins are the main components of the cell and are necessary for tissue repair, growth, cell division, and many other functions related to the physical structure of living beings (Sánchez Amador, 2020). Therefore, it is recommended that 10% to 15% of any human diet be composed of proteins (Sánchez Amador, 2020). These essential macromolecules for life are found in various foods, such as salmon, eggs, milk, legumes, beef, and many more (Sánchez Amador, 2020). According to Koshland & Haurowitz (2024), chemists recognized the importance of proteins in the early 19th century, and the Swedish chemist Jöns Jacob Berzelius coined the term "protein" in 1838. Amino Acids: The Essence of Proteins Proteins are composed of basic units called amino acids (Sánchez Amador, 2020). These molecules have a chemical structure consisting of a central carbon, an amino group, a carboxyl group, a hydrogen atom, and a variable chemical side chain. In this way, they resemble a chemical "cross" with a tetrahedral structure in three-dimensional space. According to Sánchez Amador (2020), there are twenty different amino acids that combine in various ways through peptide bonds to form proteins (polypeptide chains) found in nature. Amino acids can be classified into two types: essential and non-essential (Sánchez Amador, 2020). Essential amino acids are those that the body cannot synthesize and must therefore be obtained through the diet (Sánchez Amador, 2020). It is important to note that the "essentiality" of each amino acid depends on the type of living organism considered, as different metabolic pathways in species make some require certain compounds that others do not. On the other hand, non-essential amino acids are those the body can produce (mainly in the liver) from intermediates through transamination and are therefore not essential in the diet. Finally, according to Sánchez Amador (2020), there are conditionally essential amino acids, meaning they are needed in daily intake in specific contexts and situations. Structure Formed by linear chains of amino acids, proteins are large macromolecules that can have between a hundred and three hundred of these components, or even more (Chuan, 2021). The specific function of each protein in the body depends on the amino acids that constitute it and their order (Chuan, 2021). Although not all the functions of a protein can be explained based on its amino acid sequence, Koshland & Haurowitz (2024) mention that the properties of these biomolecules determine the correlations between the structure and function of proteins. Proteins share a common central chemical framework, consisting of a linear chain of amino acids (Sánchez Amador, 2020). This is called the "primary structure," and it conditions the nature and function of the protein in the body (Sánchez Amador, 2020). According to Koshland & Haurowitz (2024), the primary structure of a protein is defined by its sequence of amino acids, without considering the spatial arrangement of the peptide chain. However, proteins also have other more complex structures resulting from the folding of the macromolecule, its three-dimensional configuration, and other factors (Sánchez Amador, 2020). Thus, secondary, tertiary, and quaternary structures are distinguished (Sánchez Amador, 2020). The secondary structure refers to the spatial arrangement of the main peptide chain, without considering the side chains or other segments (Koshland & Haurowitz, 2024). The tertiary structure relates to the conformation of the side chains and other adjacent segments of the main chain, without considering neighboring peptide chains. Finally, according to Koshland & Haurowitz (2024), the quaternary structure applies to the arrangement of identical or different subunits of a large protein, where each subunit is a separate peptide chain. Functions Proteins vary according to the species and organ of origin (Koshland & Haurowitz, 2024). For example, the proteins found in an organism's muscles are not the same as those found in its brain or liver (Koshland & Haurowitz, 2024). However, according to Sánchez Amador (2020), all proteins have essential functions for the development and maintenance of cells and can be classified based on the tasks they perform. Among the most important functions of proteins are catalysis, regulation, protection, and structure (Sánchez Amador, 2020). Catalysis refers to the ability of proteins, especially enzymes, to accelerate the chemical reactions that occur in the body. Regulation is related to the role of proteins, such as hormones, in maintaining the balance of the organism and intervening in various physical and behavioral functions. Protection is due to the immunological function of proteins, such as antibodies, which defend the body against external agents. Structure is based on the formation of proteins, such as collagen, tubulin, and keratin, which constitute the physical parts that characterize living beings. In addition to these functions, proteins can also act as carriers, motors, pigments, energy sources, and more. In conclusion, according to Sánchez Amador (2020), proteins are indispensable for almost all biological processes in life. Classification According to their Origin Proteins can be classified based on their origin into two main groups: those of animal origin and those of plant origin (Corbin, 2016). Animal proteins are obtained from animals, such as eggs or pork. According to Corbin (2016), plant proteins are those obtained from plants, such as legumes, wheat flour, or nuts. According to their Function Proteins can be classified based on their function into different types (Corbin, 2016). On one hand, there are hormonal proteins, secreted by endocrine glands, acting as chemical messengers between cells, regulating various physiological processes. On the other hand, there are enzymatic or catalytic proteins that accelerate metabolic reactions in cells, facilitating functions such as digestion, liver detoxification, or the conversion of glycogen into glucose. Similarly, there are structural proteins, also known as fibrous proteins, which are part of tissues and organs, providing them with strength and elasticity. According to Corbin (2016), examples include collagen, keratin, and elastin, found in connective, bone, cartilaginous, capillary, nail, dental, and skin tissues. Other important proteins include defensive proteins, with immune or antibody functions, protecting the body from infections by bacteria, viruses, and other pathogenic microorganisms (Corbin, 2016). These proteins are produced in white blood cells and are responsible for recognizing and neutralizing invaders. Additionally, there are storage proteins, which store essential mineral ions such as potassium or iron for cellular balance. There are also transport proteins, dedicated to carrying minerals and other substances to cells, such as hemoglobin, transporting oxygen from the lungs to tissues. Furthermore, there are receptor proteins located in the cell membrane, controlling the passage of substances into the cell, such as GABAergic neurons, which have specific protein receptors for the neurotransmitter GABA. Finally, according to Corbin (2016), there are contractile or motor proteins that regulate the movement and force of the heart and muscles. According to their Conformation Proteins are molecules with a specific three-dimensional orientation in space, determined by the rotation of characteristic groups (Corbin, 2016). According to this conformation, proteins can be classified into two main types: fibrous proteins and globular proteins. Fibrous proteins are characterized by having polypeptide chains aligned in parallel, forming resistant and water-insoluble structures. Examples of these proteins include collagen and keratin. In contrast, globular proteins are characterized by having polypeptide chains coiled upon themselves, forming spherical and water-soluble structures. According to Corbin (2016), these proteins often have transport functions, such as hemoglobin, which carries oxygen from the lungs to tissues. According to their Composition Finally, proteins can also be classified based on their composition, i.e., the components that make them up (Corbin, 2016). According to this criterion, proteins can be divided into two groups: holoproteins or simple proteins, and heteroproteins or conjugated proteins. Holoproteins are formed solely by amino acids. Heteroproteins are those that, in addition to amino acids, contain other non-amino acid components called prosthetic groups. According to Corbin (2016), examples of heteroproteins include glycoproteins, which have sugars in their structure; lipoproteins, which contain lipids; nucleoproteins, attached to nucleic acids like chromosomes and ribosomes; metalloproteins, containing one or more metal ions, like some enzymes; and hemoproteins or chromoproteins, having a heme group, such as hemoglobin. References Chuan, A. (2021, agosto 5). Proteínas de Alto Valor Biológico: Qué son, Características y sus Fuentes. Psicología y Mente. https://psicologiaymente.com/nutricion/proteinas-alto-valor-biologico Corbin, J. A. (2016, noviembre 1). Los 20 Tipos de Proteínas y sus Funciones en el Organismo. Psicología y Mente. https://psicologiaymente.com/nutricion/tipos-de-proteinas Koshland, D. E., & Haurowitz, F. (2024). Protein. En Encyclopedia Britannica. https://www.britannica.com/science/protein Sánchez Amador, S. A. (2020, octubre 14). Proteínas: Qué son y Cómo Influyen en el Funcionamiento del Organismo. Psicología y Mente. https://psicologiaymente.com/nutricion/proteinas