A reflection on the eukaryotic cell, its organization and the concept of a typical cell

Uma reflexão sobre a célula eucariótica, sua organização e o conceito de uma célula típica

Abstract

The understanding of cell shape and structure is, perhaps, one of the most important milestones in Biology. From the discovery of the cell by Hooke in 1665 to the formulation of the cell theory by Schleiden and Schwann, there were almost 200 years of research. All these advances occurred in parallel with the progress in microscopy. Cell types were being described, organelles characterized, and cellular activity in tissues became better understood. Currently, approximately 250 different cell types are currently recognized; hence, the discussion arises: How to talk about a cell in a more introductory manner? This article discusses the concept of a “typical cell”. We believe that this concept provides students with a distorted view that is difficult to change. The morphology of cells is adapted to their function, as is their cytoplasmic content (e.g., organelles, cytoskeletal components). This fact often gets lost with the concept of a “typical cell”. In this article, We discuss an alternative approach of addressing the issue, although it is not my intention to exhaust the topic. There are many ways to break the paradigm of the typical cell and here I only intend to describe one.

Keywords:
eukaryotic cell; typical cell; cell morphology; cell function; misconceptions

Resumo

A compreensão da forma e da estrutura celular é, talvez, um dos marcos mais importantes da Biologia. Desde a descoberta da célula por Hooke em 1665 até a formulação da teoria celular por Schleiden e Schwann, foram quase 200 anos de pesquisas. Todos esses avanços ocorreram paralelamente aos avanços da microscopia. Tipos celulares foram sendo descritos, organelas caracterizadas e a atividade celular nos tecidos foi sendo mais bem conhecida. Atualmente, admite-se aproximadamente 250 tipos celulares diferentes, e é nesse ponto que levantamos uma discussão: como falar sobre uma célula de uma forma mais introdutória? Este artigo discute o conceito de uma “célula típica”. Acreditamos que isso traz uma visão deturpada aos alunos em formação que é difícil de mudar. As células têm uma morfologia adaptada à sua função e, da mesma forma, têm um conteúdo citoplasmático (organelas, componentes do citoesqueleto, etc.) adequado à sua função. Esse aspecto se perde muitas vezes no conceito de uma “célula típica”. Discutimos neste texto uma forma alternativa de abordar a questão, embora não tenhamos a intenção de esgotar o tema. Existem muitas maneiras de quebrar o paradigma da célula típica e, aqui, temos apenas a pretensão de apresentar uma delas.

Palavras-chave:
célula eucariótica; célula típica; morfologia celular; função celular; concepções errôneas

1. Introduction

The concept of cell shape and structure is perhaps one of the most important milestones in biology. When Robert Hooke (1665) published Micrographia (Micrographia: or Some Physiological Descriptions of Minute Bodies made by Magnifying Glasses, with Observations and Inquiries thereupon), a book filled with drawings and descriptions of the organisms he visualized under the newly invented optical microscope (Hooke, 1665, full paper available in the references of this article). In this historical work, the author describes different microscopic organisms. The first description of a cell was also presented. In fact, what Hooke visualized was the cavity occupied by cells in cork. Nevertheless, that work presented for the first time the concept of a cell. Since then, important discoveries regarding the structure of cells have systematically been reported.

These initial findings were followed by the work of important researchers who deservedly left their mark on the history of science by contributing substantially to the knowledge about cells. I will mention some of these distinguished researchers whom I admire, knowing that I will forget many others: Marcello Malpighi (1628-1694), Antonie van Leeuwenhoek (1632-1723), Nehemiah Grew (1641-1712), Felice Fontana (1730-1805), Robert Brown (1773-1858), Gottfried Treviranus (1776-1837), René Henri Dutrochet (1776-1847), Lorenz Oken (1779-1851), Robert Remak (1815-1865), and Rudolf Virchow (1821-1902). Due to space limitations, I will not discuss the contribution of these pioneers here. The work of each of them would deserve a discussion of its own, which I may do someday. However, based on their work, we arrived at the cell theory proposed by Matthias Jacob Schleiden (1804-1881) and Theodor Schwann (1810-1882). By working together, Schleiden, who was a botanist, and Schwann, a zoologist, noted that organisms were made up of cells. Their ideas became established and converged to form the theory that 1) all organisms are made up of cells, and 2) the cell is the basic unit of structure and organization of organisms. However, it was Rudolf Virchow who expanded these ideas by adding that 3) every cell comes from another cell (omnis cellula e cellula), 4) normal physiology, in the absence of disease, is the result of regular cellular physiology, and 5) diseases and disorders would be the result of altered physiology of the cell itself (Mazzarello, 1999). From Hooke to Schleiden-Schwann-Virchow, there were almost 200 years of research (Ribatti, 2018, Pinheiro et al., 2021). All of these advances occurred in parallel to the progress in microscopy. This story is also very interesting but I will not get into it.

The cell theory encouraged a reductionist approach to biological problems and became the most general structural paradigm of biology. In addition to being the fundamental unit of life, the cell was also recognized as the basic element of pathological processes. Diseases began to be considered an alteration of the organism’s cells (irrespective of the causative agent) (Mazzarello, 1999).

Gradually, the concept of a cell became more complex. Cell types were being described, organelles were being characterized, and cellular activity in tissues became better understood. Divided into the four basic tissues (epithelial, connective, muscle, and nervous), approximately 250 different cell types are now recognized (Karp et al., 2020). And this is where the difficulty I want to explore in this article starts: How to talk about “a cell” in a more introductory way.

The strategy is always the same, talking in general terms about the structure (plasma membrane, cytoplasm and organelles, nucleus and its components) but using an imaginary cell. We thus arrive at the concept of a “typical cell”. Many authors describe the cell in this way, especially in textbooks for high school students. The cell is displayed in exactly the same way in many university courses. On the internet, if one types the word “cell” (sometimes “cells and biology” to avoid art or cartoons) and clicks on “figure” or “image” in search engines, variations of the same image will almost always appear: a cell with no defined shape, often round or amoeba-shaped, and containing a little bit of each organelle, with these organelles having an undefined spatial distribution. The main problem is that this cell does not exist in reality.

In the present article, I will discuss the concept of a “typical cell”, which is widely used on websites and in high school textbooks. In my opinion, this provides students with a distorted view that is difficult to change. This is worsened by the fact that concepts about cellular structure are sometimes outdated or misplaced, leading to the idea that adult tissues are multifunctional since cells can do a little bit of everything. We know that this is not quite the case. I will discuss this point and describe an alternative approach, focusing my analysis on the animal cell only.

2. Materials and Methods

The bibliographic survey was conducted using primary and secondary sources, such as: the United States National Library of Medicine (MEDLINE) via PubMed; the Latin American and Caribbean Health Sciences Literature (LILACS) databases; Cochrane Library; SciVerse Scopus; Web of Science; and the Scientific Electronic Library Online (SciELO) through the Virtual Health Library (VHL) Portal. We also used books that cover the content of Cell Biology. The keywords used were: morphology and function, eukaryotic cell, cell theory, misconceptions and cell biology, typical cell and endoplasmic reticulum, typical cell and Golgi apparatus, typical cell and lysosome, typical cell and peroxisome, typical cell and nucleus, typical cell and nucleolus, typical cell and chromatin and chromosome. Subsequently, after reading and analyzing the relevant texts found, the inclusion criterion for the articles was that they addressed the morphology and function of the desired cellular structures. Finally, the main idea of this narrative was selected and grouped by similarities and differences of the information found in the texts.

3. Results and Discussion

3.1. Cellular structure

The structures that make up cells and their compartments have been recognized for a long time. Despite this, reports in the international literature concerning misconceptions about cell structure and function are present and, unfortunately, common. (Bahar et al., 1999, Tambo et al., 2003, Bouali et al., 2025).

The plasma membrane, which defines and delimits the cell, is often erroneously explained as a “film”; however, it is actually a two-dimensional fluid. Its main function is selective permeability, in addition to its incredible capacity for cellular and molecular recognition. Although many texts reasonably address the function of the plasma membrane, I have reservations as to how the structure is presented. It is of little use to talk about the lipid bilayer without commenting on its fluidity. And this is very rare. There are good texts available that describe the history of how knowledge of the plasma membrane was constructed, its activity, and particularly the importance of fluidity (Lombard, 2014, Nicolson and Mattos, 2021). This is also usually very well presented in cell biology textbooks for higher education (Carvalho and Recco-Pimentel, 2019, Karp et al., 2020, Lodish et al., 2021, Alberts et al., 2022). However, we may be failing in emphasizing the importance of this aspect to those involved in scientific publication on the internet or in writing for high school students.

Let us now move on to the description of the nucleus. This compartment is delimited by the nuclear envelope (NE), whose organization is much more complex than that of the plasma membrane. There are many texts and references (e.g., high school, internet), in which it is sometimes called karyotheca or nuclear membrane, terms that I believe to be inadequate. The NE is much more than a “nuclear membrane”; in fact, it is organized as a system of two membranes, with a space between them (known as the perinuclear space). On the other hand, in biology, theca (from the Latin word theca and the Greek word theke, which mean box, receptacle, case) usually refers to a more rigid and protective structure. The outer membrane of the NE is continuous with the endoplasmic reticulum and can therefore contain ribosomes, considering the fluidity of the membranes. On the other hand, the inner membrane of the NE is covered with a cytoskeletal structure (intermediate filaments, to be more exact), known as the nuclear lamina. However, without any doubt, the most interesting structure of the NE is the nuclear pore complex, a multimeric structure that is organized in a very precise spatial way and that controls the passage of components from and to the nucleus (Dultz et al., 2022). I could describe in detail the structure and function of the nuclear pore complex but this would exceed the scope of this article. Thus, the NE is much more than a “nuclear membrane” and is not organized as a “theca”.

The NE defines the nucleus, which contains the genetic material organized in the form of chromatin. The DNA associates with proteins in a very complex and interesting manner, forming different levels of organization that reaches its maximum level of condensation in the form of chromosomes.

I believe that the main problem at this point is that we have not been able to liberate ourselves from the paradigm that “the chromosome is condensed chromatin”. The question is not whether or not chromatin and chromosome are the same structure at different physiological stages. Some authors understand that they are (due to the different levels of compaction) and others that they are not (due to the different non-histone proteins that are associated at the highest levels of compaction). We have a healthy controversy on this issue. What appears to be a problem is that we know that, even when decondensed, just like the chromosome, chromatin occupies a defined location in the nucleus and does not mix or overlap (Cremer et al., 2006). A concept that is already two decades old. It is not about “entangled decondensed threads”, as I have read in several textbooks for high school students. The nucleus also contains the nucleolus, a non-membranous structure that, in fact, exists only because the cell transcribes rRNA for the formation of ribosomes in the cytoplasm (Lafontaine et al., 2021). Regarding the nucleolus, I noticed that very little has been described in general texts. Perhaps because of this we find fewer misconceptions. However, this is not necessarily a good thing. The nucleolus was described in 1781 by Fontana and received its nomenclature as we know it today by Valentin in 1839 (Smetana, 2011). Nevertheless, the nucleolus continues to be an unknown.

The cytoplasm contains various structures known as organelles. The endoplasmic reticulum (ER), as its name suggests, is organized as a network that runs through the cytoplasm and interconnects the cell. Many functions can be attributed to the ER, such as the synthesis of proteins (it is necessary to distinguish between proteins originating from the ER and those derived from free ribosomes) but also their modification by sulfation, glycosylation, or other processes (Schwarz and Blower, 2016). In the past, it was common to read that the ER is the cell’s “circulatory system”. Fortunately, I no longer find this type of concept. For oversimplification, the following concept is still common in Brazil: “The difference between the rough ER and the smooth ER is the presence of ribosomes”. The structure of the organelle itself, as well as its functions, are thereby neglected. However, it is difficult to break this paradigm. I do not know if colleagues from other countries encounter the same problem.

The Golgi apparatus (GA) is composed of flattened and independent saccules, in which material is continuously exchanged by vesicles. In view of its great capacity to modify (mainly by the addition of carbohydrates), package, and distribute biomolecules inside the cell or destined for secretion, this organelle is of extreme importance for biosynthetic pathways (Li et al., 2019; Agliarulo and Parashuraman, 2022). In Brazil, the myth of the “Golgi warehouse”, where the GA would “store” cellular secretions, was created in an attempt to simplify the function of the organelle; however, it distorts the essence of its activity. According to this concept, all of the organelle’s activity is lost. This was more serious in the past but this concept can still be found from time to time.

Lysosomes are responsible for intracellular digestion, a process linked to the renewal of biomolecules or organelles but also to phagocytosis for food uptake (in the case of free-living organisms) or defense (in the case of multicellular organisms) (Lawrence and Zoncu, 2019, Yang and Wang, 2021). What most calls my attention in this case is the disconnection between the lysosome and the endosome. I understand that it is a complicated relationship but I am not sure if simply omitting the organelle is a good strategy.

Peroxisomes are closely related to cellular metabolism, in which they produce and metabolize hydrogen peroxide (H₂O₂) in a countless chain of reactions that occur in the cell. These reactions are used in various processes of cellular synthesis and degradation (He et al., 2021). What I noticed is that, at high school level, only the ability of peroxisomes to degrade H₂O₂ is mentioned. This means that students do not understand this organelle. Why is it necessary to degrade H₂O₂? And why does the cell produce H₂O₂? These questions remain unanswered.

Mitochondria, as the energy-producing center of the cell (in the form of ATP), are nowadays linked to the processes of cell death by apoptosis (Javadov et al., 2020). I noticed a great deal of effort in textbooks to show the Krebs cycle and, in some cases, the energy balance. But is this enough for this organelle? I confess that I have my doubts. In any case, much of what we know about mitochondria may have to be rewritten (Hernansanz-Agustín et al., 2024). This would be a good opportunity to change the approach.

Finally, the cytoskeleton, through its components (microtubules, intermediate filaments, and microfilaments), is related to cell shape and motility (Pollard and Goldman, 2018). Intracellular movements are not addressed, which, I think, is understandable in this case.

Consequently, we find a large number of poorly founded ideas in Cell Biology, which are not easily corrected. Once these ideas are established, they become more difficult to modify. They constitute misconceptions, which are scientifically incorrect concepts that students have constructed and utilize to interpret new information. Bahar (2003) discuss this point compellingly, showing that these simplistic or deficient ideas can be acquired in various ways, such as: 1) Personal experiences (intuitive interpretations of the real world); 2) Everyday language (the use of scientific terms with different meanings in common discourse); and 3) Teachers or textbooks (formal instruction, when simplified or poorly communicated — such as the concept of a “typical cell” — can create or reinforce misconceptions). The authors also demonstrated that these misconceptions are deeply entrenched and highly resistant to instruction. The correct diagnosis of the problem thus becomes a primary concern for developing a teaching approach that can successfully remediate these conceptual flaws.

Misconceptions concerning cell structure and function were evaluated among university Biology students, assuming they should already have been familiar with these concepts from high school. The results revealed that the students had a low level of knowledge regarding the basic characteristics of cells. Misconceptions were identified across central competencies of Cell Biology education, specifically in: 1) the structure-function relationship (the most critical point), where the most frequently identified conceptual errors concerned the relationship between the structure and function of the plasma membrane, the nucleus, and the endoplasmic reticulum; and 2) Cell types, where the majority of students (68.3%) demonstrated a lack of knowledge regarding the particular characteristics of prokaryotic cells, incorrectly asserting that they possess a nucleus delimited by a nuclear envelope. This lack of knowledge was attributed to the fact that they had “always encountered the cell model with a well-defined nucleus” (the “typical cell”) in their previous studies. The study concluded that the prevalence of misconceptions constitutes a barrier to learning. It also demonstrated that the failure to establish the relationship between structure and function, and the persistence of the “typical cell” model, are conceptual flaws that extend from high school through to the university level (Bouali et al., 2025).

For a student to change a misconception, the new concept must meet four main conditions: dissatisfaction (the student must perceive that their original idea is unsatisfactory in explaining a phenomenon), intelligibility (the new concept must be clear and comprehensible), plausibility (the new concept must be compatible with new beliefs) and fruitfulness (the new concept must open up new areas of inquiry or solve problems that the old concept could not). Non-traditional teaching methods and practical activities help to force students to confront and restructure their thoughts and ideas (Bahar, 2003). However, the problem needs to be clearly established beforehand; otherwise, the strategy may fail.

3.2. The concept of the “typical cell”

Explaining a cell to children is not an easy task. It is, however, commendable that many authors are concerned about doing this. Here, my approach is to try to contribute to the topic. I noticed that many students enter university with a misconception about cells. I thus may provide some support so that the cell becomes something more tangible and understandable.

The strategy for presenting a cell is almost always the same, referring to its structure in a general manner (plasma membrane, cytoplasm and organelles, nucleus and its components). Generally, an imaginary cell is used, which contains a bit of everything (I refer to the organelles) and has an imaginary shape (usually amoeba-shaped or round). I believe that is where the problem lies. That is not how the cell is organized. That is not how cells work.

Another important point is the difficulty students have in visualizing the three-dimensionality of cells. Many students tend to describe plant cells as “rectangular” and “flat” and animal cells as “circular” instead of spherical (Vijapurkar et al., 2014). This 2-D perspective represents a cognitive resistance and hinders a clearer understanding of cellular function, as students cease to view the cell as a functional unit, considering it only a structural unit. New strategies are essential to help students visualize the cell in a 3-D manner, with emphasis on its actual shape, as a way to mitigate difficulties in understanding more complex cellular functions (Vijapurkar et al., 2014). We are in agreement with this perception. Our experience also noted some difficulty with the 3D perception of cells, and we attempted to address this using three-dimensional models of different cell types and observed a noticeable improvement (Santos Jr., et al., 2012). However, this remains an open question that requires further evaluation.

3.3. Cell shape adapted to the cell’s function

The main problem with the so-called typical cells is that they do not actually exist. Considering multicellular organisms and the specialization of cellular functions (muscle cells contract, glandular cells secrete, and so on) that occur in tissues throughout the process of cell differentiation, each cell will have its own morphology, as well as its cytoplasmic content that is also very particular (Santos Jr., et al., 2019). I will give some examples.

Erythrocytes (or red blood cells) are enucleated in mammals, while the erythrocytes of other vertebrates such as birds, reptiles, amphibians, and fish are nucleated and oval. The blood of some Antarctic fish may contain neither erythrocytes nor hemoglobin. However, oxygen supply to their tissues is adequate because oxygen concentrations are high in cold water, while the metabolism of fish is low (McMillan and Harris, 2018). Human erythrocytes have a biconcave disk shape (Figure 1A). When suspended, they have a mean diameter of 7.5 µm and a thickness of 2.6 µm near the rim and of 0.8 µm in the center. The biconcave shape of normal erythrocytes provides a large surface area relative to their volume, which facilitates gas exchange (Shiga et al., 1990, Junqueira and Carneiro, 2012). Changes in the morphological pattern (shape, size, color, inclusions, and arrangement) of erythrocytes are associated with various pathologies (Ford, 2013).

Figure 1
Morphology of cells found in animal and human tissues. (A) Human erythrocyte or red blood cell (Leishman stain); (B) rat dermal fibroblasts (hematoxylin and eosin staining); (C) chondrocyte of rat articular cartilage (hematoxylin and eosin staining); (D) osteocyte of rat long bone (Masson’s trichrome stain); (E) skeletal striated myocyte of rat tongue (hematoxylin and eosin staining); (F) human vaginal desquamative cytology (Papanicolaou method). Scale bars: 20 µm.

Fibroblasts are found in connective tissues (Figure 1B). These cells have an elongated morphology and cytoplasmic extensions. Since fibroblasts are characterized by relevant activity, their nucleus contains decompacted chromatin and an evident nucleolus. The cytoplasm is rich in rough ER and GA. This feature is characteristic of a secretory cell. In this case, the cells secrete extracellular matrix (ECM) components, particularly collagen, elastin, and glycosaminoglycans (Junqueira and Carneiro, 2012, Alberts et al., 2022). There are not a very large number of lysosomes since fibroblasts are not specialized in digestion. I could write several pages about this cell since I find it fascinating; however, I will limit myself to saying that fibroblasts are currently understood as a population with heterogeneous functions, whose activity varies according to the location of the cell in the different organs where it is found (Lynch and Watt, 2018).

In cartilage, we have chondrocytes (Figure 1C). Immersed in the cartilaginous matrix, chondrocytes are round and appear in isogenous groups of up to eight cells. Chondrocytes are cells specialized in the production of ECM and in the maintenance of cartilage homeostasis through the production of enzymes, growth factors, and inflammatory mediators. The ECM of cartilage is directly related to the volume or function of chondrocytes and is composed of fibers (collagen and elastin), proteoglycans, and glycoproteins. These components are synthesized and maintained by the chondrocytes themselves (Archer and Francis-West, 2003, Carballo et al., 2017). The cytoplasm of this cell is filled with rough ER and GA. However, the entire metabolism of the chondrocyte is set to operate at low oxygen tension (ranging from 10% on the surface to <1% in deep layers), with most of the cell’s energy requirements being supplied by glycolysis; hence, chondrocytes normally do not contain abundant mitochondria (Archer and Francis-West, 2003).

Osteocytes (Figure 1D) are cells with a poorly developed ER and GA and the nucleus contains condensed chromatin. These cells are found inside the bone matrix, where they occupy lacunae, and their cytoplasmic extensions pass through canaliculi, thereby permitting intercellular communication. Morphologically, osteocytes are flattened cells with abundant long and thin extensions. This morphology can be explained by the fact that the cell is enclosed within a highly rigid and impermeable ECM (or bone matrix). Osteocytes thus use these extensions to receive nutrients from blood vessels and for cell-cell interactions. Therefore, a continuous and integrated network of osteocytes exists along the bone (Robling and Bonewald, 2020, Palumbo and Ferretti, 2021).

Muscle cells, on the other hand, have a very well-defined morphology. Myocytes possess a highly specialized cytoskeleton that uses chemical energy to generate mechanical force in the form of cellular contraction. Skeletal and cardiac muscles are called striated muscles because of the so-called transverse striations that can be seen under a light microscope. This visible organization corresponds to repeated units of contractile filaments, known as sarcomeres, in bundles called myofibrils. In mature striated fibers, most of the cell volume is occupied by myofibrils. Cytoplasmic organelles such as GA, mitochondria, ER (called sarcoplasmic reticulum in muscle), glycogen granules, and other organelles/structures are found around the myofibrils. On the other hand, smooth muscle cells contain large amounts of actin and myosin filaments that are not organized into sarcomeres. The skeletal muscle fiber (Figure 1D) is multinucleated, containing peripheral nuclei. The cardiac muscle fiber is mono-, bi- or trinucleated, with central nuclei, while the smooth myocyte is mononucleated, containing central nuclei (Sweeney and Hammers, 2018).

I could give many other examples but I think it would be too long. In fact, there is no typical cell (without a defined morphology, with organelles distributed randomly and at the same proportion) in multicellular organisms. Something similar can be seen when a cytological smear of the vagina is performed (using the well-known Papanicolaou method). In this case, cells appear to have the shape of a typical cell (Figure 1E). But this is a mistake. The cells lining the vagina (like those of the cheeks, esophagus, etc.) are flat. Playing the devil’s advocate, perhaps during embryogenesis some cells have characteristics resembling a typical cell. However, these features are rapidly lost as cell differentiation progresses (Santos Jr., et al., 2019). Therefore, the classic representation of the “typical cell” seen on the internet, which consists of an amoeboid cell that contains a little bit of each organelle, would only be found in the amoeba. It is worth noting that protozoa possess different structures (e.g., vacuoles, cytopharynx, hydrogenosomes, mitosomes) not found in cells of multicellular organisms (Cavalier-Smith, 2013). Thus, the typical amoeba-shaped cell is only observed in amoeba and with some reservations.

The observations presented are neither solely empirical nor personal. One report identified several problematic conceptions in Cell Biology, many of which stem from the excessive simplification of the cell concept. When confronted with electron micrographs of various cell types, many students had difficulty identifying which ones would be typical of a eukaryotic cell. Furthermore, the relationship between the cell type and the structure required for its function was often unclear; in other words, there was a failure to connect morphology with cellular functional activity. The study concludes that the misconceptions are deep-seated and can negatively influence the comprehension of more complex biological concepts (Tambo et al., 2003).

The picture is being constructed that is, at the very least, alarming. Students are able to memorize functions and name structures, yet they fail to integrate knowledge; that is, they do not understand how the physical or molecular shape of an organelle facilitates its specific role (Bouali et al., 2025). In a systematic literature review, Fernández Fernández and Jiménez Tejada (2018) also point to the failure in the form-function relationship as the core of a learning issue. The authors further identify the difficulty in connecting the form/structure (morphology or molecular) of organelles and the cell with their specific functions (physiology) as the main type of conceptual error. This is a significant problem. In cancer, for example, the pathologist looks for characteristics such as cell shape and organization to establish the diagnosis (I am obviously simplifying and not addressing special stains for histopathology or the investigation of specific markers). The loss of cell shape and organization defines the histopathological diagnosis.

I understand that we must change the way we present the cell to students who are having initial contact with it. If we are going to use a typical cell in elementary and high school, we need to start saying that this cell does not exist in reality. Or we may have to use a differentiated cell as a model. A muscle cell, a chondrocyte, a fibroblast, or an osteocyte, who knows. In addition, it is necessary to describe what differentiates these cells from each other. In their Cellular Biology textbook, the late professors Junqueira and Carneiro (2012) (I am citing, as a homage, the last published edition when at least one of these famous professors was still alive; there is a more recent edition, which is very interesting by the way) have always used a hepatocyte as a model. This seems to be a more correct approach. Perhaps, because they are also histology professors, these authors have encountered the same difficulties as I describe here. In his textbook, Professor Karp (Karp et al., 2020) uses a typical cell to conceptualize the cell; however, immediately thereafter, the author shows a diagram with different cell types from different tissues. This is also an interesting approach.

4. Conclusion

My teenage daughter thinks that cells are “something very boring”. It is difficult to contradict her, knowing how this information is provided to her. Regarding cells and cellular structures, there is an important difficulty, i.e., the depth that concepts in high school textbooks must have. It would perhaps be important that we make an effort to better advise the authors of these books on how to address this content. Simplification is undoubtedly important but only if it is correct. The morphology of cells is adapted to their function. Likewise, the cytoplasmic content (organelles and cytoskeletal components) of cells is also adapted to their function. If the function of the cell changes, its shape and cytoplasmic content will change too. I understand that these concepts, which are so basic and important, end up being almost lost in many approaches to cells and cellular structures.

Concurrently, in higher education, it is necessary to be aware of the difficulties incoming students face with concepts related to cell form and function. Many bring misconceptions that are challenging to change. New teaching approaches are important in this regard. However, for such approaches to be effective, it is essential to clearly comprehend the specific difficulties students present. Approaches that seek to foster the understanding of three-dimensionality and the principle that different cells have different functions must be reinforced.

I believe that, in higher education courses, we must get rid of the concept of the typical cell and use more realistic models (for example, chondrocytes, hepatocytes, fibroblasts, among others). This would render the concept of cells more accessible in general courses, especially those not linked to biological sciences. Perhaps this type of approach should be introduced earlier, still in high school. I do not intend to exhaust this subject. Likewise, I do not intend to present a definitive or finalized version of the issue. There are many ways to break the paradigm I am discussing. The way I address it in this article is one of them. Other experiences are, without a doubt, very welcome.

Acknowledgements

I would like to thank my students who, over the years, have spoken about the issues addressed in this manuscript and who motivated me to write it.

• Data Availability Statement
  The data contained in this manuscript are reflections made by the author on the topics addressed in this article. Therefore, they do not constitute physical data, but rather ideas that can be discussed publicly and at any time with the author.

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Edited by

• Editor:
  Takako Matsumura Tundisi

Data availability

The data contained in this manuscript are reflections made by the author on the topics addressed in this article. Therefore, they do not constitute physical data, but rather ideas that can be discussed publicly and at any time with the author.

Publication Dates

• Publication in this collection
  06 Mar 2026
• Date of issue
  2026

History

• Received
  20 Aug 2025
• Accepted
  29 Dec 2025