Prokaryotic and Eukaryotic Cells

Prokaryotic and eukaryotic cells are the two kinds of cells forming all life on earth. Prokaryotes are always unicellular, whereas eukaryotic cells can be multicellular or unicellular. In 1937, French researcher Chatton created the prokaryote/eukaryote nomenclature to divide living beings into two main classes: prokaryotes (bacteria) and eukaryotes (organisms with nucleated cells). 

Prokaryotic cells

These are abundantly available from the gut of a being to the Earth’s surface and contribute significantly to its biomass. Prokaryotes, or prokaryotic cells, are known to be ancestors of eukaryotes with simpler single-celled structures. The size of prokaryotes is smaller than the smallest eukaryotes but more significant than a virus. The small size is due to the lesser DNA content required for the production of proteins.

Due to their smaller size, prokaryotic cells have a large surface-to-volume ratio (comparing the surface area of the cell to the volume of the cell), thus allowing easy entry of substances into the cell. Examples of prokaryotic cells include bacteria, archaebacteria, cyanobacteria and mycoplasma.

Eukaryotic cells

Eukaryotic cells have a nucleus enclosed within a nuclear envelope. Eukaryotic cells typically contain other membrane-bound organelles such as mitochondria, Golgi apparatus, chloroplasts, vacuole, lysosomes, endoplasmic reticulum, ribosome etc. 

Similarities between prokaryotic and eukaryotic cells

1. The cell membrane 

A lipid bilayer is an organisation of phospholipids and proteins found in eukaryotic and prokaryotic cells that serve as a selective barrier between the cell’s internal and exterior environments.

2. Genetic information 

Both eukaryotic and prokaryotic species store genetic information in deoxyribonucleic acid (DNA). Creating RNA through transcription and subsequently translating it into proteins requires this genetic material to govern and instruct cell function.

3.Ribosomes

Ribosomes aid in the translation of RNA and protein production, both of which are necessary for the survival of eukaryotic and prokaryotic cells.

Differences between prokaryotic and eukaryotic cells

1. The most crucial distinction is that eukaryotes have “real” nuclei that house their DNA, whereas prokaryotes’ genetic material is not membrane-bound.

2. A prokaryotic cell’s diameter generally ranges between 0.1 and 5.0 micrometres. Eukaryotic cells typically range from 10 to 100 micrometres in diameter.

3. The cell wall is present in prokaryotic cells and is exceedingly complex, while eukaryotic cells have cell walls quite rarely, and if they do, they are chemically simple.

4. The true nucleus is absent in prokaryotic cells, but a nucleotide is discovered in the central part of the cell, whereas, in eukaryotic cells, the actual nucleus is present.

5. In prokaryotic cells, DNA is structured in a circular shape; in eukaryotic cells, DNA is arranged in a linear shape.

6. The cytoplasm is found in prokaryotic cells, although absent from most cell organelles. It comprises both cytoplasm and organelles in eukaryotic cells, and both are present.

7. Ribosomes in prokaryotic cells are 70S (large unit 50S and small unit 30S), whereas ribosomes found in eukaryotic cells are 80S (large unit 60S and small unit 40S). 

8. Only asexual reproduction occurs in prokaryotic cells. Eukaryotic cells can reproduce both sexually and asexually. 

9. The flagella of prokaryotic and eukaryotic cells differ, with eukaryotes having a microtubule structure linked to the cell membrane through the basal body. In contrast, prokaryotes have flagella positioned outside the plasma membrane.

10. The microtubular organisation and type of movement of prokaryotic and eukaryotic flagella differ. The organisation in eukaryotes is (9 + 2) and specialised, whereas the arrangement in prokaryotes is (9 + 0) and simple.

Conclusion

Prokaryotes are single-celled creatures that belong to the Bacteria and Archaea domains. They have a cell wall made up of cellulose, peptidoglycans, or murein, along with a capsule that protects the cell from dying. Prokaryotic cells are much simpler compared to eukaryotic cells. The DNA in prokaryotes is naked and does not have a nuclear membrane, making DNA replication and cell division easier without undergoing mitosis. A eukaryotic cell has a plasma membrane, cytoplasm and ribosomes, just like a prokaryotic cell. Still, it usually is bigger has a genuine nucleus and additional membrane-bound organelles that allow for functional compartmentalisation.