- Beyond eukaryotes and prokaryotes: The 11 types of cells.
12 Differences between eukaryotic and prokaryotic cells
The two large groups into which these basic units are divided are made up of prokaryotic and eukaryotic cells, which have features that distinguish them from each other.
The first of the differences between eukaryotic and prokaryotic cells is found in their origin. As its name indicates, prokaryotic cells are more basic units than eukaryotes (the prefix ‘proto’ already gives us an idea that they are ancient living beings). By contrast, eukaryotic cells are a step further in the evolution of prokaryotes.
It is calculated that between the appearance of one and the other cells there would be almost 2000 million years of separation, 1,700 being exact.
2. A cytoskeleton composed of different proteins
Although it is a common element in cells, as we will see later, the cytoskeleton of eukaryotes is composed of complex organelles (microtubules and protein filaments); while the one belonging to prokaryotes consists of more elementary proteins.
3. Size and shape
If we have a microscope, we can see that, due to their complexity, eukaryotic cells are larger than prokaryotic cells .
Another difference that we find between these two classes of cells lies in their shape: prokaryotes are more elongated and tubular, while eukaryotes tend to be more rounded.
4. Ways of storing genetic material
Again, we can appreciate differences between eukaryotic and prokaryotic cells if we pay attention to the characteristics related to the storage of their genetic material. In the first place, in prokaryotic cells, being more primitive units, it appears scattered throughout the cytoplasm ; while in eukaryotes it remains compartmentalized within the nucleus.
5. Different number of chromosomes
Due to their more elementary condition, prokaryotic cells contain a single chromosome , while eukaryotes have countless chromosomes.
6. Composition of the plasma membrane
Although its function is the same (to separate the inside of the cell from the outside), another of the most defining differences between prokaryotic and eukaryotic cells is in the internal composition of one of its parts.
On this occasion, its dissimilarity refers to the composition of this structure: the plasmatic membrane of prokaryotes is formed from murein or peptidoglycan (like the wall of many bacteria); while in the others, it is made of phospholipids.
7. Flagella of varied complexity
The flagella (cellular structures that favor movement) constitute another of the most notable differences between eukaryotic and prokaryotic cells. Prokaryotes have very simple flagella., made from a basic protein, as a “tail” or “rudder”. Instead, eukaryotic flagella are made up of several protein chains and microtubules.
8. Nucleoid and nucleus
Probably this is one of those features that gives one of the biggest differences between eukaryotic and prokaryotic cells, and that has to do with the cell nucleus.
Prokaryotes lack a nucleus , causing the organelles to be scattered throughout the interior of the cell in what is called a “nucleoid.” In contrast, eukaryotic cells contain a nucleus with a cell membrane that allows collecting the most important organelles, which contain the information of the DNA (Golgi apparatus, endoplasmic reticulum and lysosomes, among others).
9. DNA is arranged differently
As a consequence of the previous point, we find another of the differences between prokaryotic and eukaryotic cells in the way of storing genetic material.
In the first case, as they are older cell groups, the DNA is stored within the nucleoid. This, as it does not have a cell membrane, cannot be considered a structure in itself, as would be the nucleus itself.
However, in eukaryotic cells, the DNA is contained within the nucleus , which, having a cell membrane, allows the structure to be distinguished from the rest of the interior of the cell.
10. Form of reproduction
If we pay attention to their form of reproduction, we find that prokaryotes are considered asexual cells: they only multiply their DNA so that it passes, by nuclear fusion, to form a new individual.
On the other hand, eukaryotes, although they pursue the same objective (transmitting their DNA), do so following a process of mitosis or meiosis, depending on whether they are cells of animal or plant origin.
11. Absence or presence of mitochondria
Prokaryotic cells do not have mitochondria , a type of organelle essential for cell respiration, basic in eukaryotes. Instead, prokaryotes have a series of enzymes that are responsible for oxidizing molecules.
12. They form different organisms
Finally, the last of the differences between eukaryotic and prokaryotic cells has to do with the most elementary function assigned to them: the creation of higher organisms.
In the case of prokaryotic cells, these form unicellular organisms , such as bacteria, the most basic beings in nature. Instead, eukaryotic cells produce beings of greater cellular complexity: fungi, plants or animals, among others.
There are differences between eukaryotic and prokaryotic cells, but also similarities
Although their nature is not the same, prokaryotic and eukaryotic cells share certain features that we must highlight to see that their ultimate goal is essentially the same.
1. They must be nourished to be able to perform their functions
In the first place, despite the differences between eukaryotic and prokaryotic cells, both must receive food for their sustenance , as well as interact with their peers and, finally, multiply.
2. They are DNA storage units
It is in the cells where the hereditary genetic material that must be transmitted (DNA) is contained, therefore it is important that the vital functions are covered in order to give rise to a healthy individual. In this sense, their morphology is similar, since they are covered by a cell membrane, composed of lipids , which serves as protection, also allowing them to be distinguished and separated from each other.
3. Prokaryotes and eukaryotes have a cell membrane
The cell membrane protects an interior that, whatever type it may be, is made up of proteins, carbohydrates, minerals, fats and vitamins. Prokaryotic and eukaryotic cells alike are endowed with ribosomes , a type of molecule that allows the genetic expression of DNA.
4. They have cytoplasm
If we observe them under a microscope, we will appreciate the differences between eukaryotic and prokaryotic cells just by looking at their shape, but in both classes we can see that they have cytoplasm, a part of the interior of the cell delimited by the membrane and surrounding the nucleus or nucleoid.
cytoskeleton to maintain structure
The cytoskeleton is the internal support of the cell, which allows it to retain its shape and from which the other parts are organized. Likewise, the cytoskeleton confers a certain dynamism to both kinds of cells, making their movement possible.
- More differences: The 8 differences between animal and plant cells.