Animal cell: types, parts and functions that characterize it

The animal cell is the minimum unit of functionality that makes up living beings belonging to the category of animals, the Kingdom Animalia.

Specifically, it is a type of eukaryotic cells that, combining with each other and sometimes collaborating with other forms of life (for example, bacteria that make up the intestinal flora) form functional tissues and organs, which allow the existence and survival of a animal.

In this article We will see what are the characteristics of the animal cell, as well as their main functions and specializations in forming the organism in which they live.

• Related article: "The 10 branches of Biology: its objectives and characteristics"

Characteristics of this biological unit

All animal cells belong to the taxon of eukaryotic cells. These are characterized by containing all their genetic material in a structure known as the cell nucleus, and also contain different organelles separated from the rest by a membrane that covers them, unlike prokaryotic cells, which are smaller and do not have the above characteristics (for example, their DNA is scattered throughout the cytoplasm that fills their inside).

In addition, the animal cell is distinguished from the rest of eukaryotes by the fact that it organizes with others to form multicellular organisms that belong to the kingdom of animals.

At the same time, Animals are living things of both microscopic and macroscopic size. which are characterized, among other things, by their ability to move and by having nerve cells, among other things. He Animalia Kingdom It is one of the 5 kingdoms that we find in the group of eukaryotes.

Parts of the animal cell

These are the main parts and structures that make up animal cells.

1. Core

The nucleus is arguably the most important part of the animal cell, because it not only contains an "instruction manual" on which molecules to synthesize to build and regenerate certain parts of the cell, but it is also a strategic plan for the operation and maintenance of the organism of which the cell is a part. cell.

In other words, the nucleus contains all the information related to what must be done inside the cell and also outside it. This is so because within this structure, which consists of a membrane that covers it, the genetic material is protected, that is, the DNA contained in the form of a helix and folded into different chromosomes.

In this way, the nucleus acts as a filter for what enters and leaves the area where the DNA or deoxyribonucleic acid remains stored, so that it does not spread. disperse and get lost, and trying to minimize that certain molecules come into contact with the chromosomes and destabilize or alter the genetic information contained in them. they.

Of course, as we will see, in animal cells there is still another cellular structure that contains genetic material and that is not inside the nucleus.

2. Cellular membrane

The cell membrane is the outermost layer of the cell, so it covers almost the entire cell and protects all its parts equally. It is made up of a set of lipids in which some proteins with specialized functions are interspersed/or embedded in these layers.

Of course, the cell membrane of animal cells, like those of any other eukaryotic living being, are not totally impermeable, Rather, they have certain entry and exit points (in the form of pores) that allow the exchange of substances with the outside.

This increases the risk of harmful elements getting inside, but at the same time it is necessary to maintain homeostasis, the physical-chemical balance between the cell and its environment.

3. Cytoplasm

The cytoplasm is the substance that fills the space between the nucleus and the cell membrane. That is, it is the substance that acts as a physical support for all the internal components of the cell. Among other things, it contributes to the fact that substances necessary for the animal cell to develop, or regenerate, or communicate with others are always available within the cell.

4. cytoskeleton

The cytoskeleton is un set of more or less rigid filaments that have the objective of giving shape to the cell and keeping its parts more or less always in the same place.

Besides, allow certain molecules to travel through their internal channels, like tubes (in fact, some components of the cytoskeleton are called “microtubules”).

5. mitochondria

Mitochondria are one of the most interesting parts of the animal cell, because they contain their own DNA, different from that of the nucleus. It is believed that this structure is actually the remnant of a union between a cell and a bacterium. (mitochondrion being the bacterium inserted into the cell, fused in a symbiotic relationship).

When reproduction takes place, copies of the mitochondrial DNA are also made to pass on to the offspring.

The main function of mitochondria is the production of ATP., a molecule from which animal cells extract energy, so mitochondria are very important for metabolic processes.

6. Golgi apparatus

The Golgi apparatus is primarily responsible for create molecules from raw materials that come to it from other parts of the animal cell. Thus, it intervenes in very diverse processes, and they all have to do with the repair and production of new materials.

7. Endoplasmic reticulum

Like the Golgi apparatus, the endoplasmic reticulum is also characterized by synthesizing materials, but in this case it does so on a smaller scale. Specific, It is especially involved in the creation of lipids with which to maintain the cell membrane.

8. lysosomes

Lysosomes are involved in the degradation of cellular components to recycle their parts and put them to better use. They are microscopic bodies that release enzymes with the ability to "dissolve" elements of the animal cell.

• You may be interested in: "The 4 differences between the animal cell and the plant cell"

Types and functions

we can establish a classification of animal cells according to their functions and type of tissues and biological organs that usually constitute by grouping together. Let's see what these basic categories are. Of course, not all are present in all forms of animal life.

1. Epithelial cells

This type of animal cell forms superficial structures and supports the rest of the tissues. They form the skin, glands, and certain specialized tissues that cover parts of organs.

2. connective cells

These cells aim create an interconnected structure that, beyond the skin, keeps all the internal parts in place. For example, bone cells, which are included in this category, form bones, rigid structures that hold other elements in place.

3. Blood cells

This type of animal cells allow all the nutrients, vitamins and molecules necessary for life to travel to through the circulatory system, on the one hand, and prevent harmful external agents from spreading through the body, through the other. Thus, their activity is linked to movement.

Red blood cells and white blood cells are included in this category., or erythrocytes and leukocytes, respectively.

4. Nerve cells

This is one of the most characteristic cell types of animal activity, since these living beings characterized by their ability to move and process many types of information corresponding to this constant change of environment.

This is a category that includes neurons and glial cells, thanks to which nerve impulses travel through the body.

5. muscle cells

muscle cells form fibers with the ability to contract and relax depending on the orders that arrive through the nervous system.

Bibliographic references:

• Boisvert, F.M. (2007). The Multifunctional nucleolus. Nature Reviews Molecular Cell Biology.
• Cavalier-Smith, T. (1998). A revised six-kingdom system of life». Biological Reviews of the Cambridge Philosophical Society (Cambridge University Press), 73: pp. 203 - 266.
• Lamond A.I.; Earnshaw, W.C. (1998). Structure and function in the nucleus. Science. 280 (5363): 547 - 553.
• Miller, K. (2004). Biology. Massachusetts: Prentice Hall.
• Nemeth, A. (2010). Initial Genomics of the Human Nucleolus. PLoS Genetics 6(3). doi: 10.1371/journal.pgen.1000889
• Pisani, D.; Cotton J.A.; McInerney, J.O. (2007). Supertrees disentangle the chimerical origin of eukaryotic genomes. Molecular Biology and Evolution. 24(8). pp. 1752 - 1760.
• Stuurman, N.; Heins, S.; Aebi, U. (1998). "Nuclear lamins: their structure, assembly, and interactions". Journal of Structural Biology. 122 (1–2): 42 - 66.