Similarities and differences between prokaryotic and eukaryotic cells (2023)

Here in this post, we will briefly talk about the similarities and differences between prokaryotic and eukaryotic cells.

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

Prokaryotic cells are generally the most primitive cell type with few functionalities. All metabolic activities of organisms take place only within this single cell.

On the other hand, eukaryotes are those organisms that have the eukaryotic cells. These are multicellular organisms and have membrane bound organelles.

Eukaryotic cells have evolved from prokaryotic cells over millions of years. In eukaryotes, cells make up tissues, then organs, then organ systems, and then the body with categories of cells that perform different types of metabolic activities.

So, let's get to know the similarities and differences between prokaryotic and eukaryotic cells. I will first talk about the similarities and then systematically about the differences.

Similarities Between Prokaryotic and Eukaryotic Cells

Similarities in the 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 contains 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 (buy water). These are oriented outwards and inwards of the cell.

4. In the plasma membrane, the lipid tail of each phospholipid molecule is hydrophobic in nature (aversion to water). These are oriented outwards to each other and thus keep away from the water, inside and outside the cell.

5. It is not permeable to ions, proteins and other molecules, although it is permeable to other molecules that can move through the membrane.

Similarities in genetic material

1. Both prokaryotic and eukaryotic cells use double-stranded DNA (deoxyribonucleic acid) as the cell's genetic material.

2. In both eukaryotes and prokaryotes, DNA molecules are condensed with the assistance of various proteins. In eukaryotes, DNA is wrapped around proteins called histones. In prokaryotes, DNA is wrapped around proteins called HU, which are not histone proteins but are similar to them.

3. In both cell types, transcription occurs to form RNA, which is later translated into proteins. Thus, protein synthesis can be observed in both cell types.

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

5. During DNA replication, DNA helicase unwinds the DNA double strand and then the new DNA strand is replicated from the old strand using DNA polymerase.

6. Prokaryotic and eukaryotic genomes contain noncoding DNA that helps form small noncoding RNA molecules that affect 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 cell types, ribosomes facilitate RNA translation and then protein synthesis.

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

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

Similarities in the cytoplasm

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

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

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

4. The cytoplasm along with the cell membrane helps give the cell shape and size.

5. Cytoplasm also supports the exchange of materials between the interior of the cell and the outside world across 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 produce identical daughter cells.

2. In both cell types, cell growth occurs first, followed by division of the genetic material and the whole cell, including the replication of ribosomes.

3. No matter what, all cells originate from pre-existing cells through the process of cell division only in both cell types.

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

(Video) EUKARYOTIC CELLS vs PROKARYOTIC CELLS | What's the difference?

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Differences between prokaryotic and eukaryotic cells

Difference Between Prokaryotes and Eukaryotes - (in a Table)

Differences in the cell membrane

1. In prokaryotes, the cell envelope consists of 3 layers, namely the outer glycocalyx, the middle cell wall and then the inner plasma membrane. In animal eukaryotic cells, the cell wall consists only of the plasma membrane.

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

3. The prokaryotic plasma membrane differs from the eukaryotic in that it has an essential fold called the mesosome. Mesosomes are formed by extending the plasma membrane into the cell.

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

5. The prokaryotic cell membrane consists of peptidoglycan, a cross-chain of N-acetyl-glucosamine and muramic acid. Whereas the eukaryotic cell membrane is basically trilamellar with a bilayer of phospholipid structure.

Differences in cell organelles

1. The nucleus is present in eukaryotes. The nucleus is absent in prokaryotes.

2. The endoplasmic reticulum is absent in prokaryotes. In eukaryotes, the endoplasmic reticulum is present and consists of two types: smooth ER and rough ER.

3. Mitochondria are absent in prokaryotes. Eukaryotes have double-membrane mitochondria.

4. In prokaryotes there are 2 subunits of prokaryotic ribosomes: 50S and 30S units which when present together form the 70S prokaryotic ribosomes. In eukaryotes, there are 2 subunits of eukaryotic ribosomes: 60S and 40S units, which together form the 80S eukaryotic ribosomes.

5. Prokaryotes lack the Golgi apparatus. The Golgi apparatus is present in eukaryotes.

6. Microtubules are absent in prokaryotes. Microtubules are present in eukaryotes.

7. In prokaryotes, the cytoskeleton may be present. In eukaryotes, the cytoskeleton is present.

8. Nucleoids and plasmids are present in prokaryotes. In eukaryotes, plasmids may be present but the nucleoid is absent.

differences in genetic material

1. Prokaryotes are haploid, meaning there is only a single copy of each gene. Since eukaryotes are diploid, there are two copies of each gene in each cell.

2. In prokaryotes, there is a single chromosome made up of a single, double-stranded, circular DNA that floats freely in the center of the cell's cytoplasm and is called a nucleoid. In eukaryotes, DNA is organized into multiple linear chromosomes located in the cell nucleus.

3. Because prokaryotes do not have a true nucleus, the single haploid chromosome is coiled in a region of the cytoplasm called the nucleoid. Eukaryotes have a true nucleus and hence the various chromosomes are located within it and the structure within the nucleus is the nucleoplasm which is not membrane bound and where the active synthesis of ribosomes and RNA located in the nucleolus takes place.

4. DNA in prokaryotes is smaller, circular, and present in the cytoplasm, while eukaryotic DNA is larger, organized in chromosomes, and localized in the nucleus.

5. The nucleic acids present in eukaryotes are only DNA, but some prokaryotes, such as retroviruses, contain RNA as genetic material.

6. Prokaryotic DNA is circular in nature with both ends connected. Whereas eukaryotic DNA is linear in nature, coiled and supercoiled to compress into a small space within the nucleus.

7. Prokaryotes contain several hundred to several thousand genes. While eukaryotes contain over 23,000 genes.

differences in cell division

1. Cell division in prokaryotes is faster, easier and completed much faster compared to eukaryotes.

2. Cell division in prokaryotes occurs by binary fission (asexual), while cell division in eukaryotes occurs mitotic (asexual) and meiotic (sexual).

3. In prokaryotes, cell division is very easy as DNA replication occurs first, then chromosome separation, and finally the cell divides to form two new daughter cells. In eukaryotes, cell division is very complex compared to prokaryotes, since mitosis occurs first, which is a very long multi-step process, then karyokinesis, cytokinesis and identical daughter cells are formed.

4. Since prokaryotes are unicellular, asexual binary fission allows cell division to form a new organism. In eukaryotes, sexual reproduction occurs where meisos 1 and then meiosis 2 occur with a series of multistep cell division processes that form a diploid zygotic cell from the haploid gamete cells.

Differences in the cytoplasm

1. In eukaryotic cells, the cytoplasm includes all material inside the cell and outside the nucleus. In prokaryotes, it contains all the materials that are inside the cell because there is no nucleus inside.

2. In eukaryotes, the cell organelles found in the cytoplasm are mitochondria, Golgi bodies, endoplasmic reticulum, ribosomes, etc. In prokaryotes, the cytoplasm contains plasmids, ribosomes, inclusion bodies, and nucleoids.

3. In the prokaryotic cell, the cytoplasm is the only place where most of the chemical reactions and metabolic pathways that pass through the cell take place. In eukaryotic cells, few metabolic pathways occur in the cytoplasm and most occur within the nucleus.

4. In prokaryotes, DNA replication, RNA formation and protein synthesis take place in the cytoplasm. In eukaryotes, all of these processes take place within the cell nucleus.

5. In eukaryotes, the cytoskeleton, composed of microtubules, actin filaments, and intermediate filaments, runs through the cytoplasm and provides structural support for the cell. In prokaryotes, the cytoskeleton passing through the cytoplasm is rarely present and hence the cell envelope provides structural support to the cell.