Difference Between Prokaryotic and Eukaryotic Cell

Distinguish between prokaryotes and eukaryotes

Currently, all organisms that live on our planet and have a cellular structure are divided into two groups - prokaryotes and eukaryotes. Representatives of the first group are prokaryotes (from the Greek pro - to and karyon - the core), or pre-nuclear, - the oldest organisms on the planet. They appeared in the aquatic environment of the Earth about 3.5 billion years ago and may have been the first cellular organisms that gave rise to the whole variety of modern and extinct life forms.

Modern systematics distinguishes prokaryotes into a separate kingdom - Monera , which includes bacteria and blue-green algae, or cyanobacteria.

The second group of cellular organisms is eukaryotes  (from Greek eu - true, karyon - nucleus), or nuclear. According to the generally accepted theory of evolution, the first eukaryotes evolved from the oldest prokaryotes about 2 billion years ago. All eukaryotes are representatives of three kingdoms: fungi, plants and animals .

Representatives of both groups are united by the cellular structure , therefore, both prokaryotes and eukaryotes are characterized by all the signs of a living thing: they are an integral system, carry out metabolism, grow, develop, multiply, evolve, etc.

Prokaryotic and Eukaryotic are two different types of cells and both are completely different from each other. In this article we explain difference between Prokaryotic and eukaryotic cell so that you can distinguish them perfectly in your preparation.

Difference between Prokaryotic cell and Eukaryotic Cell Pdf

Prokaryotic Cell Eukaryotic Cell
The Cell which carry primitive or undeveloped nucleus is called as prokaryotic cell. The cell which carry true or develop nucleus is called eukaryotic cells.
The size of cell is generally range from 0.2 micrometers to 2.0 micrometers in diameter Eukaryotic cells range from 10 to 100 micrometers in diameter.
Simpler in structure More complex in comparison to prokaryotic cells
The organelles in prokaryotic cells are not membrane-bound The organelles in eukaryotic cells are certainly specific in function. Most noteworthy, they are membrane-bound
In this cells true nucleus absent, instead nucleotide is present True nucleus is present.
DNA is arranged in circular shape DNA is linear in shape
In prokaryotic cells, cytoplasm is present, but it is lacking in most cell organelles. In eukaryotic cells, it consists of both cytoplasm and organelles, both are present.
The cell wall is present here. Furthermore, it comprises of mucopeptide or peptidoglycan Usually, there is an absence of cell wall here. However, in case it is present, it comprises cellulose
Cell division occur through binary fission, transduction, conjugation, and transformation Cell division occur through mitosis
Mitochondria is absent Mitochondria is present and it is a powerhouse of cells.
The endoplasmic reticulum is not present in prokaryotic cells. The endoplasmic reticulum is present in eukaryotic cells.
Ribosome is present  Smaller size 70S, distributed in the cytoplasm. Larger size 80s, found on membranes as in endoplasmic reticulum; 70s present in organelles such as chloroplast and mitochondria.
Plasmids are commonly found in prokaryotes. Plasmids are very rarely found in eukaryotes
In this cells only asexual reproduction occurs. Both sexual and asexual reproduction occurs.
These cells have a single origin of replication These cells have multiple origins of replication
Only one chromosome is there in a prokaryotic cell. There are many chromosomes present in the eukaryotic cells.
Bacteria and Archaea are the major examples of prokaryotic cells. Plant cell and animal cells are the major examples.

What are the difference between Prokaryotic cell and Eukaryotic cell

The sizes of prokaryotic cells, as a rule, do not exceed 10 microns, which is much smaller than eukaryotic ones. The smallest cells of prokaryotes are no more than 0.2 x 0.3 microns in size, however, a real giant among bacteria with a size of 100 x 10 microns was also found. Eukaryotic cells are usually much larger, varying in volume by thousands of times.

The most obvious and fundamental difference is the presence or absence of nucleus. In prokaryotes, the main genetic material is located in the center of the cell in the cytoplasm in the form of a circular DNA moleculeor nucleoid, which is attached to the plasma membrane and is not surrounded by a nuclear membrane. Along with the nucleoid in prokaryotic cells, a small circular DNA molecule may be present - plasmid. Plasmids can move from one cell to another and integrate into the basic nucleotide.

Unlike prokaryotes, an obligatory component of a eukaryotic cell is the nucleus, surrounded by a double nuclear membrane and including linear DNA molecules. The DNA is also present in mitochondria and chloroplasts.

Prokaryotic cells, as well as eukaryotic cells, are separated from the environment and other cells by the plasma membrane , which in both groups has a similar structure. However, the cell membrane of prokaryotes forms mesosomes - numerous invaginations into the cytoplasm containing enzymes that provide metabolic processes. On top of the plasma membrane of prokaryotes is a membrane consisting of carbohydrates - pectin and murein. Some eukaryotic cells also have a strong cell wall. For example, the cell wall of fungi includes chitin, the cell wall of lower plants consists of cellulose and glycoproteins, and in higher plants - from cellulose and pectin.

The cytoplasm of prokaryotes compared to the cytoplasm of eukaryotes is much poorer in the presence of organelles. Membrane organelles (mitochondria, plastids, Golgi complex, endoplasmic reticulum, lysosomes) are absent in prokaryotes. Their functions are performed by mesosomes. Ribosomes, smaller than those of eukaryotes, are randomly distributed throughout the cytoplasm of a prokaryotic cell. Prokaryotes do not have a cytoskeleton. Some have organelles of movement - flagella.

Metabolism in prokaryotes and eukaryotes is carried out in different ways. According to the method of nutrition, I distinguish four groups of organisms: photoautotrophic - use the energy of sunlight to synthesize organic substances (plants, some bacteria); photoheterotrophic - use the energy of organic substances synthesized by photoautotrophs (animals, fungi, bacteria); chemoautotrophic , chemoheterotrophic organisms use the energy of chemical reactions (bacteria). Prokaryotes use all four methods of nutrition, while eukaryotes themselves synthesize energy from sunlight, or use readymade energy stored by photoautotrophs.

Prokaryotes are anaerobic , i.e. able to live and develop in the absence of free oxygen. Instead of molecular oxygen, such organisms can use other compounds, for example, salts of nitric, sulfuric and carbonic acids. For many anaerobes, oxygen is a poison.

The term "anaerobes" was introduced in 1861 by Louis  Pasteur , who discovered microbes of butyric fermentation.

Anaerobic organisms live in the soil, at great depths in the seas, in the waters of deep oil sources, in bottom sediments and play an important role in the chemical transformations of organic and inorganic substances. Some anaerobic bacteria as symbionts adapted to living in the intestines of humans and animals are involved in digestion by breaking down the cellulose of plant cells. Pathogenic anaerobes can cause gas gangrene and tetanus in humans.

Most eukaryotes are aerobic, i.e. can live and develop only in the presence of free oxygen. Almost all animals, plants and many microorganisms have an oxidative type of metabolism: they use for life the energy released as a result of oxidation reactions under the influence of free oxygen.

Prokaryotes reproduce, as a rule, asexually - by dividing the cell in half, sometimes by budding. Before cell division, bacterial DNA doubles, after which the cell is divided transversely into two equal parts. Prokaryotes multiply at a tremendous rate. Under favorable conditions, cell division occurs every 20-30 minutes, and bacteria are able to quickly increase their numbers in a short period of time.

Prokaryotes reproduce sexually much less frequently, however, it is very important. During the sexual process, bacteria can exchange both sections of circular DNA and plasmids that integrate into the bacterial chromosome. This increases the resistance of bacteria to adverse environmental factors, such as drugs.

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