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Prokaryotes vs. Eukaryotes

All living organisms can be grouped into two types based on their fundamental cell structure. They are prokaryotes and eukaryotes, and the cells they possess are called prokaryotic cells and eukaryotic cells.

Prokaryotes are primitive organisms lacking a nucleus and membrane-bound organelles. The term ‘prokaryote’ is derived from the Greek words ‘pro’, meaning ‘before’ and ‘karyon’, meaning ‘kernel’. Together it means ‘before nuclei’. In contrast, eukaryotes are advanced organisms with a well-defined nucleus and membrane-bound organelles. The term ‘eukaryotes’ is derived from the Greek words ‘eu’, meaning ‘good’ and ‘karyon’, meaning ‘kernel’, meaning ‘true nuclei’. The eukaryotes are thought to have originated from the prokaryotes about 2.7 billion years ago.

Compare and Contrast Prokaryotic and Eukaryotic Cells

Although they share some common characteristics, prokaryotic and eukaryotic cells differ in most aspects, such as cell size, shape, organization, and life cycle, including reproduction. The main differences are given below.

What is the Difference between Prokaryotic and Eukaryotic Cells

BasisProkaryotic CellEukaryotic Cell
1. ExamplesCells of bacteria, archaea or archaebacteria, and cyanobacteria or blue-green algaeCells of plants, animals, fungi, algae, and protozoa (protists)
2. TypeUnicellularUnicellular or multicellular
3. Size (in diameter)0.1 to 5.0 μm10 to 100 µm
4. Type of OrganizationSimpleComplex
5. Cell WallUsually presentMade of peptidoglycan or mucopeptideUsually absentIf present (in plants and fungi) made of cellulose
6. NucleusAbsent. Instead, have a nucleoid that is devoid of the membranePresent and membrane-bound
7. DNACircular, double-strandedFound freely in the cytoplasmNaked (not bound to proteins)Little repetitive DNA and no introns  Linear, double-strandedFound within the nucleusBound to histone proteinsA large amount of repetitive DNA and introns
8. Chromosome NumberSingle haploid (n) chromosomePaired diploid (2n) chromosome
9. PlasmidPresent.Absent.
10. Ribosome type70S type, with 50S and 30S subunitsSmaller in size compared to the eukaryotic cell80S type, with 60S and 40S subunitsLarger in size compared to the prokaryotic cell
11. MitochondriaAbsentPresent
12. ChloroplastAbsent. Chlorophyll scattered in the cytoplasmPresent in plants and algae
13. Endoplasmic ReticulumAbsentPresent
14. Golgi ApparatusAbsentPresent
15. LysosomesAbsentPresent
16. PeroxisomesAbsentPresent
17. MesosomePresentAbsent
18. CentrosomeAbsentPresent except for flowering plants
19. CytoskeletonAbsentPresent
20. FlagellaMicroscopic in sizeSimple in structure, made of protein, flagellin  Submicroscopic in sizeComplex in structure, with 9+2 arrangement of microtubules
21. CiliaAbsentPresent
22. Mode of ReproductionBoth asexual and sexualMostly sexual
23. Cell DivisionAsexually by binary fission and sexually by conjugation, transformation, and transductionThrough mitosis
24. Generation TimeShorter (20 to 60 minutes) than eukaryotesLonger (12 to 24 hours) than prokaryotes
25. Metabolic RateHigher than eukaryotesLower than prokaryotes
26. RespirationVia cytoplasm membraneVia mitochondria
27. Electron Transport ChainFound in the cell membraneFound in the mitochondrial membrane
28. DNA ReplicationOccurs in the cytoplasmHas one origin of replicationOccurs in the nucleusHas multiple origins of replication
29. Transcription and Translation (Protein Synthesis)Occurs simultaneouslyBoth occur in the cytoplasmOccurs one after the otherTranscription occurs in the nucleus and translation in the cytoplasm
30. Gene Expression (Regulation)Expressed in groups called operonsExpressed individually
31. Cytoplasmic StreamingAbsentPresent
32. GlycocalyxPresent in capsule or slime layerPresent in cells lacking a cell wall

What do Prokaryotes and Eukaryotes have in Common

Both prokaryotic and eukaryotic cells are alike in some ways and share some common features that are given below:

  • Plasma Membrane, an outer covering that allows selective entry and exit of substances in and out of the cell, is found in both cell types. Their fundamental composition in forming a lipid bilayer with embedded proteins is also the same.
  • Both contain cytoplasm, a jelly-like fluid that fills the cell’s entire interior where all other cellular components are found.
  • DNA is the genetic material in both cell types.
  • In both, ribosomes help in protein synthesis.

FAQs

Q1. Are viruses prokaryotic or eukaryotic?

Ans. Viruses are not cells and thus are neither a prokaryote nor a eukaryote.

Q2. Is Amoeba prokaryotic or eukaryotic?

AnsAmoeba, being a protist, are eukaryotes.

Q3. Is yeast prokaryotic or eukaryotic?

Ans. Yeast, being fungi, is a eukaryote.

Q4. Are eubacteria prokaryotic or eukaryotic?

Ans. Eubacteria, or ‘true’ bacteria, are a class of bacteria and thus are prokaryotes.

Q5. Is E. coli prokaryotic or eukaryotic?

AnsE. coli,being bacteria, is a prokaryote.

Q6. Are human cells prokaryotic or eukaryotic?

Ans. Human cells have a true nucleus and membrane-bound organelles and thus are eukaryotes.

Q7. Is Euglena prokaryotic or eukaryotic?

AnsEuglena, being protist, are eukaryotes.

Q8. Are Cyanobacteria prokaryotic or eukaryotic?

Ans. Cyanobacteria or blue-green algae lack membrane-bound organelles and well-organized nuclei and thus are prokaryotes.

Q9. Did eukaryotes evolve from prokaryotes?

Ans. Yes. Eukaryotes originated at least 2.7 billion years ago, following almost 1 to 1.5 billion years of prokaryotic evolution.

Q10. How is protein synthesis different in prokaryotes and eukaryotes?

Ans. Prokaryotic protein synthesis uses 70S ribosomes in comparison to 80S ribosomes in eukaryotes. Protein synthesis in prokaryotes is a continuous process with transcription. On the other hand, in eukaryotes, protein synthesis starts after transcription is complete.

Q11. Is Elodea prokaryotic or eukaryotic?

AnsElodea is a plant genus, and thus is a eukaryote.

Q12. Are onion cells and cheek cells prokaryotic or eukaryotic?

Ans. Onion cells and cheek cells are eukaryotic cells because they possess membrane-bound organelles and a well-organized nucleus.

Q13. Is mold prokaryotic or eukaryotic?

Ans. Mold, being fungi, is a eukaryote.

Q14. Is HIV eukaryotic or prokaryotic?

Ans. HIV, being a virus, is neither a prokaryote nor a eukaryote.

Q15. Is Streptococcus prokaryotic or eukaryotic?

AnsStreptococcus is a bacterial genus and thus is a prokaryote.

Q16. Are cancer cells prokaryotic or eukaryotic?

Ans. As cancer cells are found only in multicellular organisms, which are eukaryotes, they are eukaryotic cells.

Q17. Is a red blood cell prokaryotic or eukaryotic?

Ans. All red blood cells, including rodent red blood cells, are eukaryotic because they have a true nucleus and membrane-bound organelles.

Q18. Is a fish prokaryotic or eukaryotic?

Ans. Fish cells, including sharks, are eukaryotic because they have a true nucleus and membrane-bound organelles.

Q19. Is Monera prokaryotic or eukaryotic?

Ans. Monera is a kingdom that includes bacteria and archaea. They have a prokaryotic cell organization.

Q20. Is Saccharomyces prokaryotic or eukaryotic?

Ans. Saccharomyces is a genus of fungi, including many yeast species. They are thus eukaryotes.

Q21. Is Spirillum prokaryotic or eukaryotic?

Ans. Spirillum is a bacterial genus and thus is a prokaryote.

Q22. Is Vibrio cholera prokaryotic or eukaryotic?

Ans. Vibrio cholera, being bacteria, is a prokaryote.

Article was last reviewed on Saturday, February 13, 2021

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