Similarities and Differences between Prokaryotic and Eukaryotic cells

Here in this post, we will briefly talk about the similarities and differences between the Prokaryotic and Eukaryotic Cells.

We all know that the Prokaryotes are those organisms that possess the prokaryotic cell. These are unicellular organisms and do not have membrane-bound cell organelles.

Prokaryotic cells are usually the most primitive type of cells with not many functionalities. All the metabolic activities of the organisms are done within this single cell only.

Whereas, on the other hand, Eukaryotes are those organisms that possess the Eukaryotic cells. These are multicellular organisms and have membrane-bound organelles.

Eukaryotic cells are evolutionarily developed from the prokaryotic cells over the course of millions of years of history. In eukaryotes, the cells form tissues, then organs, then organ systems, and then the body with categories of cells doing different types of metabolic activities.

So, let us know the Similarities and Differences between Prokaryotic and Eukaryotic cells. I will talk about the Similarities first and then the differences systematically.

Similarities between Prokaryotic and Eukaryotic cells

Similarities in Cell Membrane

1. Both Eukaryotic and Prokaryotic Cells have a semi-fluid phospholipid bilayer cell membrane. This is also known as the plasma membrane.

2. The cell membrane holds all the material inside the cell and the cytoplasm is the fluid that is present inside the cell membrane.

3. In the plasma membrane, the phosphate head of each phospholipid molecule is hydrophilic (water-loving). These are oriented towards the outside and inside of the cell.

4. In the plasma membrane, the lipid tail of each phospholipid molecule is hydrophobic (water-hating) in nature. These are oriented towards each other the outside thus remaining away from the water, inside and outside of the cell.

5. Its non-permeable to ions, proteins, and other molecules, while permeable to other molecules that may move through the membrane.

Similarities in Genetic Materials

1. Both prokaryotic and eukaryotic cells use the double-stranded DNA (Deoxyribonucleic Acid) as the genetic material of the cell.

2. In both eukaryotes and prokaryotes, the DNA molecules are condensed with the support of different proteins. In eukaryotes, the DNA is wrapped around proteins called Histones. In prokaryotes, the DNA is wrapped around proteins called HU which are not Histone proteins but similar to it..

3. In both the type of cells, transcription takes place to form RNA which later translates to proteins. Thus, protein synthesis can be seen in both the types of cells.

4. Both follow the semi-conservative model of DNA replication. In this process, DNA-dependent DNA Polymerase is used as a catalyst.

5. During DNA replication, DNA Helicase unwinds the double-stranded DNA chain and then the new DNA strand is replicated from the old strand using DNA Polymerase.

6. Prokaryotic and eukaryotic genomes both contain non-coding DNA which helps in the formation of small non-coding RNA molecules that influence gene expression.

Similarities in Ribosomes

1. Ribosomes are present in both Prokaryotic and Eukaryotic Cells. It consists of a large subunit and a small subunit.

2. In both the types of cells, ribosomes facilitate RNA translation and then the synthesis of proteins respectively.

3. These are granule like structures and in both the organisms, the ribosomes are similar in structure. These ribosomes are complexes of rRNA molecules and proteins

4. Ribosomes are the sites in a cell in which protein synthesis takes place. Within the ribosome, the rRNA molecules direct the catalytic steps of protein synthesis.

Similarities in Cytoplasm

1. The cytoplasm found in the prokaryotic cells is the same as the cytoplasm in eukaryotic cells. It is a gel-like fluid found bounded by the plasma membrane.

2. It is a viscous substance present inside the cell in which all of the other cellular materials remain suspended.

3. It is the gel-like cytosol, a water-based solution that contains ions, small molecules, and macromolecules.

4. The cytoplasm along with the cell membrane helps in providing the shape and size to the cell.

5. The cytoplasm also helps in the exchange of materials between the inside of the cell and the outside world through the plasma membrane.

Similarities in Cell Division

1. Prokaryotes follow Binary Fission of Cell Division and Eukaryotes follow Mitotic Cell division.  The similarity is that both produces identical daughter cells.

2. In both the type of cells, cell growth occurs first and later followed by the division of the genetic material and the entire cell, including replication of the ribosomes.

3. No matter what, all cells come from preexisting cells through the process of cell division only in both types of cells.

4.  All of the cell parts and organelles must be duplicated and then separated when the cell divides.

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Differences between Prokaryotic and Eukaryotic cells

Difference Between Prokaryotes and Eukaryotes – (In a Table)

Difference Based Upon Properties	PROKARYOTIC CELL	EUKARYOTIC CELL
DOMAIN	Archaea and bacteria	Protista, fungi, plant and animal
CELL SIZE	Basically 0.2-2.0 micrometer in diameter	Basically 10-100 micrometer in diameter.
NUCLEUS	No true nucleus	Possesses true nucleus
NUCLEAR MEMBRANE	Absent	Present
GENEIC MATERIAL	DNA or RNA usually single stranded, not complexed with histone protein	Linear DNA present usually complexed with histone protein
INTRONS IN GENE	Rarely present	Present in most of them
PLASMID	Plasmid DNA are present in some of them	Plasmid DNA are not common
GENOME	Haploid genome	Diploid genome
CYTOPLASMIC MEMBRANE	Usually lack sterols but hopanoids may be present	Hopanoids are present but sterols are absent
RIBOSOME	Ribosome is of 70S	Generally 80S but that of mitochondria and chloroplast is of 70S
MYCOLAGINOUS CAPSULE	Present	Absent
MEMBRANE BOUND ORGANELLES	Absent	Present in varied number
CELLULAR RESPIRATION	Mitochondria absent, respiratory system is generally a part of the cytoplasmic membrane	In mitochondria of the cell
ENDOSPORES	Present in some of them, they are very heat resistance	Absent
GAS VESICLES	present	Absent
CELL WALL	Present in most of them, some of them are composed of peptidoglycan layer, and some of them of polysaccharides or glycoprotein	Present in plant algae and fungi and absent in animals.
PLASMA MEMBRANE	Lacks receptors	Contains many receptors
CYTOSKELETON	Not present	Present
MODE OF REPRODUCTION	Asexual	Both sexual and asexual
FLAGELLAR MOVEMENT	Flagella composed of single type of protein i.e. simple ,flagella rotate	Cilia or flagella made up of complex mictrotubule,donot rotate
NON-FLAGLLAR MOVEMENT	Gliding movement	Amoeboid movement

Differences in Cell Membrane

1. In Prokaryotes, the cell envelope is composed of 3 layers i.e. outer glycocalyx, the middle cell wall, and then the inner plasma cell membrane. In animal Eukaryotic cells, the cell wall is composed of only the plasma cell membrane.

2. In prokaryotes, although each layer of the envelope performs distinct functions, they act together as a single protective layer. In eukaryotic animal cells, only the plasma cell membrane acts as a protective layer. In the eukaryotic plant cells, the outer Cell wall and the inner plasma cell membrane acts as a protective layer.

3. The prokaryotic plasma membrane is different from eukaryotic as it posses essential infolding called mesosomes. Mesosomes are formed by the extension of the plasma membrane into the cell.

4. In eukaryotes, plasma membrane consists of sterols and carbohydrates.In only a few species of prokaryotes, plasma membrane with carbohydrates or sterols can be seen.

5. The prokaryotic cell membrane is composed of Peptidoglycan that is a cross-chain of N-acetyl-glycosamine and Muramic acid. Whereas, the Eukaryotic cell membrane is basically tri-lamellar with a double layer of phospholipid structure.

Differences in Cell Organelles

1. Nucleus is present in Eukaryotes. In Prokaryotes, nucleus is absent.

2. In Prokaryotes, Endoplasmic Reticulum is absent. In Eukaryotes, Endoplasmic Reticulum is present and it is of two types: Smooth ER and Rough ER.

3. In Prokaryotes, Mitochondria is absent. In Eukaryotes, double membrane-bound Mitochondria is present.

4. In Prokaryotes, 2 subunits of Prokaryotic ribosomes are: 50S and 30S units, which when present together form the 70S prokaryotic ribosomes. In Eukaryotes, 2 subunits of Eukaryotic ribosomes are: 60S and 40S units, which together form the 80S eukaryotic ribosomes.

5. In Prokaryotes, Golgi Apparatus is absent. In Eukaryotes, Golgi Apparatus is present.

6. In Prokaryotes, Microtubules are absent. In Eukaryotes, Microtubules are present.

7. In Prokaryotes, Cytoskeleton may be present. In Eukaryotes, Cytoskeleton is present.

8. In Prokaryotes, Nucleoid and Plasmids are present. In Eukaryotes, Plasmids may be present but Nucleoid is absent.

Differences in Genetic Materials

1. Prokaryotes are haploid meaning that only a single copy of each gene is present. Whereas, Eukaryotes are diploid meaning two copies of each gene are present in each cell.

2. In Prokaryotes, there is a single chromosome that is composed of a single double-stranded circular DNA floating freely in the center of the cytoplasm of the cell called nucleoid. In Eukaryotes, the DNA is organized into multiple linear chromosomes found in the nucleus.

3. As the prokaryotes lack a true nucleus so, the single haploid chromosome is coiled up in a region of the cytoplasm called the nucleoid. The Eukaryotes have a true nucleus and so the various chromosomes lie within it, and the structure inside the nucleus is the nucleoplasm which is not membrane-bound and where active ribosomal and RNA synthesis takes place that is in the nucleolus.

4. The DNA in prokaryotes are smaller in size, circular, and present in cytoplasm while, the eukaryotic DNA is larger in size, arranged on chromosomes and located in the nucleus of the cell.

5. The nucleic acid present in eukaryotes are only DNA however, some prokaryotes such as retrovirus contains RNA as their genetic material.

6. The prokaryotic DNA is circular in nature with both the ends joined together. Whereas, eukaryotic DNA is linear stranded in nature which is coiled and supercoiled to compress itself into a small space inside the nucleus of the cell.

7. The prokaryotes contain several hundred to a few thousand genes. Whereas, Eukaryotes contain more than 23,000 genes.

Differences in Cell Division

1. Cell division In Prokaryotes is completed faster, simpler way, and very rapidly as compared to the Eukaryotes.

2. Cell division in Prokaryotes takes place by Binary Fission (asexually) whereas, in Eukaryotes cell division takes place Mitotically (asexually) and Meiotically (sexually).

3. In prokaryotes, cell division is very simple as first DNA replication takes place, then Chromosome Segregation, and at last the cell divides forming two new daughter cells. In Eukaryotes, cell division is very complex as compared to the prokaryotes as the first mitosis takes place which is a very long multi-step process, then karyokinesis, then cytokinesis, then identical daughter cells are formed.

4. Since prokaryotes are unicellular, so asexual binary fission of cell division lets to the formation of a new organism. In Eukaryotes, sexual reproduction takes place where Meisos 1 and then Meiosis 2 occurs with a series of the multi-step cell division process forming a diploid zygote cell from the haploid gamete cells.

Differences in Cytoplasm

1. In eukaryotic cells, the cytoplasm includes all of the material inside the cell and outside of the nucleus. In prokaryotes, it contains all materials located inside the cell as there is no nucleus inside.

2. In Eukaryotes, the cell organelles that are found in the cytoplasm are mitochondria, Golgi bodies, Endoplasmic Reticulum, Ribosomes, etc. In Prokaryotes, the cytoplasm contains plasmids, ribosomes, inclusion bodies, and nucleoid.

3. In Prokaryotic cell, the cytoplasm is the only place where most of the chemical reactions and metabolic pathways that run the cell takes place. In Eukaryotic cells, only a few metabolic pathways occurs in the cytoplasm and the majority occurs inside the nucleus.

4. In prokaryotes, DNA replication, RNA formation, and Protein synthesis all takes places in the cytoplasm. In Eukaryotes, all these processes takes place inside the nucleus.

5. In Eukaryotes, cytoskeleton that is made up of microtubules, actin filaments, and intermediate filaments passes through the cytoplasm and gives the structural support to the cell. In prokaryotes, cytoskeleton passing through the cytoplasm is rarely present and so the cell envelope gives the structural support to the cell.