THE Cell biology, also called Cytology, is the part of biology that is dedicated to the study of cells and their structures. It is a very important area, since the cell is the smallest living unit of an organism and is used to differentiate a living being from a non-living being.
The cells began to be studied from the work with cork carried out by Robert Hooke in 1665. This British researcher was the first to visualize cells under a microscope. As he checked dead cork cells, he believed that these structures were just empty chambers, hence the name cell, which means small cell.
With the development of microscopes and more in-depth studies on other materials, it was realized that all living beings had cells and these were much more complex than the structures visualized by Hooke. The works of the botanist Mathias Schleiden and the zoologist Theodor Schwann were fundamental for the construction of the so-called Cell Theory, which said that all living beings were composed of cells.
In 1855, Rudolf Virchow published a paper in which he claimed that all cells originated from another preexisting cell. However, it was only in 1878 that Walther Flemming observed the process of cell division and was able to prove how the multiplication of cells occurred.
The conclusions obtained in these two works were incorporated into the Cell Theory, which is currently known for three main points:
→ All living organisms are made up of one or more cells;
→ Cells are the functional units of living beings;
→ A cell only originates from an existing one.
Currently, it is assumed that cells are made up of three basic parts: the membrane, the cytoplasm and the core. It is worth noting, however, that the most correct thing is to admit that all cells have genetic material, since not all of them have a nucleus delimited by a nuclear membrane, also called caryotheca. Cells that do not have a nuclear membrane are called prokaryotic cells, and those with the membrane are called eukaryotic.
THE plasma membrane of a cell has as its main function to control what enters and what leaves this structure. Thanks to this important feature, we say that it has selective permeability. The model that best represents the structure of the membrane currently is the fluid mosaic model, which admits that it is formed by a phospholipid bilayer where proteins are immersed.
O cytoplasm is a viscous liquid present between the nucleus and the membrane where the organelles, which are structures responsible for the most varied functions of the cell. By analyzing cell organelles, it is also possible to see the difference between a eukaryotic and a prokaryotic cell. In the latter only ribosomes are found, while in the eukaryotic a wide range of organelles is observed.
See below the main organelles visualized in a cell:
→ endoplasmic reticulum smooth – It is mainly related to the synthesis of lipids and carbohydrates.
→ Rough endoplasmic reticulum – Responsible for intense protein synthesis.
→ ribosome – Relates to protein synthesis.
→ Golgiian Complex – Its main function is cell secretion.
→ Mitochondria – Involved in the cellular respiration process.
→ Lysosome – Exclusive organelle of animal cells, the lysosome is related to intracellular digestion.
→ centriole – It has an important role in cell division.
→ peroxisome – Destroys toxic substances.
→ Chloroplast – It acts in the photosynthesis process, not being found, therefore, in animal cells.
→ vacuole – Related to intracellular digestion and accumulation of substances.
Since the understanding that living beings are formed by cells to the present day, a lot of knowledge about Cell Biology has been acquired. Despite this, there are still many studies to be carried out. Below you will find texts that will help you to broaden your knowledge about this field of studies.
By Ma. Vanessa dos Santos