At cells are the structural and functional units of the living beings. All living beings are made up of cells, with the exception of virus, which are acellular organisms. Some organisms are made up of a single cell (unicellular beings), others, in turn, are made up of several cells (multicellular beings).
Cells perform different functions and have some basic parts: plasma membrane, cytoplasm and genetic material, which may or may not be delimited by a nuclear envelope. Cells can be classified into two major groups: prokaryotes and eukaryotes. Humans have eukaryotic-like cells.
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Cell summary
Cell is the structural and functional unit of living beings.
Viruses are acellular organisms.
There are different types of cells, which perform different functions.
All cells have a plasma membrane, cytoplasm and genetic material.
Prokaryotic cells do not have core, while eukaryotic cells have a true nucleus.
Eukaryotic cells can be divided into plant and animal cells.
Plant cells have cell wall, central vacuole and plastids, structures absent in animal cells.
What are cells?
Cells are the unitss structureis it worksis of living beings. They are called structural units, as they form the body of living beings. Imagine, for example, a big wall. This wall is formed by small structures, the bricks. Each brick would be a cell, which, together with the others, helps to form a multicellular organism (a living being made up of more than one cell).
Furthermore, in single-celled organisms, the cell represents the entire organism. In addition to being structural, they are functional units of living beings, and are so called because they are living units, capable of producing energy and reproducing, for example.
The term cell was coined in 1665 by Robert Hooke. Cell comes from Latin, cell, which means “small cell”. Hooke proposed this term because he observed a cut of cork under a microscope and found only dead cells. Therefore, he only verified the presence of the cell wall of these structures and, therefore, found such a cell-like structure. |
Where do we find cells?
All living things are made up of cells, with the exception of viruses. They are found forming the bodies of organisms. Some living beings like bacteria and protozoa, have the body formed by only a single cell. Other organisms, however, are multicellular, being made up of several cells. In some multicellular organisms, cells are grouped into tissues, which constitute organs, which are grouped into systems.
What are the functions of cells?
There are different types of cells, each adapted to a particular function. As mentioned, in some organisms, such as protozoa and bacteria, cells represent the entire living being, as these beings are unicellular. In this case, they perform all the functions responsible for their survival.
In multicellular organisms, in turn, there are specialized cells that play different roles. You leukocytes, for example, are cells found in our body that act to protect the body against disease-causing agents. You neurons they are cells that act ensuring the propagation of the nerve impulse. Red blood cells, in turn, ensure the transport of oxygen throughout the body.
Read more: Stem cells – capable of transforming into any cell and a hope for medicine
Basic parts of a cell
Cells are small but very complex structures. Generally speaking, we can say that all cells have three basic components: the plasma membrane, the cytoplasm and the genetic material.
Plasma membrane: is a structure formed by a bilayer of lipid molecules with several proteins inserted. It surrounds the entire cell, separating and protecting all its components from the external environment. The membrane has the ability to select what enters and what leaves the cell. Due to this function, we say that it has selective permeability.
Cytoplasm: in prokaryotic cells, it corresponds to the entire internal region of the cell. In eukaryotic cells, in turn, the cytoplasm corresponds to the region between the plasma membrane and the nuclear envelope and is the place where the organelles cytoplasmic. In it, several important chemical reactions take place in eukaryotic cells.
Genetic material: contains the information that determines the characteristics of a living being. In eukaryotic cells, most of the genetic material is contained in the nucleus, which is surrounded by a double membrane, the nuclear envelope. In prokaryotic cells, in turn, there is no nuclear envelope delimiting the genetic material.
Read too: DNA - responsible for transmitting all genetic information to daughter cells
Cell classification
Cells can be classified into two basic groups: prokaryotic and eukaryotic.
prokaryotic cells
The prokaryotic cells are characterized by not having a defined core. In these cells, the genetic material is not bounded by a nuclear envelope. Furthermore, in prokaryotic cells, there is no presence of membranous organelles (small structures present in the cytoplasm that perform different functions within the cell, such as intracellular digestion and production of energy). You ribosomes, structures responsible for protein synthesis, are present. As an example of organisms that have prokaryotic cells, we have bacteria and cyanobacteria.
eukaryotic cells
Eukaryotic cells are those that have a true nucleus, with the genetic material surrounded by a nuclear envelope. In these cells, membranous organelles, such as mitochondria, golgiense complex and endoplasmic reticulum. As in prokaryotic cells, the presence of ribosomes is observed. Examples of organisms that have eukaryotic cells are animals, plants, protozoa, seaweed and fungi.
Eukaryotic cells can be grouped into two types: plant cells and animal cells. Plant cells differ from animal cells due to the presence of three structures: cell wall, central vacuole and plastid.
The cell wall of plant cells is mainly made up of cellulose and is located outside the plasma membrane. The cell wall provides greater resistance to the plant cell. The central vacuole is an organelle that has different functions, such as ensuring the maintenance of cell pH and storing substances. Finally, we have the plastids, the best known type being the chloroplast, which is related to the photosynthesis.
