Which difference between prokaryotic and eukaryotic cells is most asked in NEET?

The presence vs absence of a true (membrane-bound) nucleus and membrane-bound organelles, and the 70S vs 80S ribosome distinction. NEET phrases these straight from the NCERT Class 11 "Cell — The Unit of Life" chapter, so revise the exact NCERT wording rather than a paraphrase.

Are mitochondria 70S or 80S?

70S — the same as prokaryotes — even though mitochondria sit inside a eukaryotic cell. This (plus their own circular DNA) is direct evidence for the endosymbiotic theory and is a classic NEET trap, because the surrounding cytoplasm uses 80S ribosomes.

Is the mesosome found in eukaryotic cells?

No. The mesosome is a plasma-membrane infolding exclusive to prokaryotes. Eukaryotes never have mesosomes — they use mitochondria for the respiratory functions a mesosome assists with in bacteria.

Do prokaryotic cells have a cell wall like plant cells?

Both have a cell wall, but the chemistry differs — and that is the testable point. Bacterial walls are made of peptidoglycan (murein), plant walls of cellulose, fungal walls of chitin; animal cells have no wall at all.

Are viruses prokaryotic or eukaryotic?

Neither. Viruses are not cells — they are acellular entities with nucleic acid (DNA or RNA) enclosed in a protein coat (capsid), so the prokaryote/eukaryote classification does not apply to them.

Do eukaryotic cells have 70S ribosomes?

Yes — but only inside their mitochondria and chloroplasts, which have their own 70S ribosomes (and circular DNA). The ribosomes free in the eukaryotic cytoplasm and on the rough ER are 80S. This dual presence is the core evidence for the endosymbiotic theory and a very common NEET MCQ.

What is the main difference between prokaryotic and eukaryotic DNA?

Prokaryotic DNA is a single, circular, naked molecule (no histones) lying free in the nucleoid region, often with extra circular plasmids. Eukaryotic DNA is linear, wrapped around histone proteins to form chromatin/chromosomes, and enclosed in a membrane-bound nucleus.

Is a mesosome found in prokaryotic or eukaryotic cells?

The mesosome is found only in prokaryotes (bacteria). It is an infolding of the plasma membrane that increases surface area and helps in respiration, secretion, DNA replication and distribution to daughter cells, and formation of the new cell wall during division.

Last Updated: 19 June 2026Verified for JEE 2027

BiologyNEET

Difference Between Prokaryotic Cell and Eukaryotic Cell

Prokaryotic and eukaryotic cells are the two fundamental cell types. Prokaryotes lack a membrane-bound nucleus, while eukaryotes have a well-defined nucleus and organelles.

Prokaryotic Cell vs Eukaryotic Cell — Comparison Table

Aspect	Prokaryotic Cell	Eukaryotic Cell
Nucleus	No true nucleus (nucleoid)	Membrane-bound nucleus
Size	Small (1-10 μm)	Large (10-100 μm)
Organelles	No membrane-bound organelles	Mitochondria, ER, Golgi, etc.
DNA	Circular, no histones	Linear, with histones
Ribosomes	70S	80S
Cell wall	Present (peptidoglycan)	Present in plants (cellulose), absent in animals
Nucleolus	Absent	Present
Endomembrane system	Absent (no ER, Golgi, lysosomes)	Present (ER, Golgi, lysosomes, vacuoles)
Cell division	Binary fission — no spindle, no mitosis	Mitosis / meiosis with spindle apparatus
Flagella structure	Simple, made of flagellin (no 9+2)	Complex 9+2 microtubule arrangement
Reproduction	Binary fission	Mitosis and meiosis
Examples	Bacteria, Archaea, Cyanobacteria, Mycoplasma, PPLO	Plants, Animals, Fungi, Protists

Key Points to Remember

Prokaryotes evolved first (~3.5 billion years ago)

Endosymbiotic theory: mitochondria and chloroplasts were once prokaryotes

Prokaryotes can have plasmids (extra-chromosomal DNA)

Both types have plasma membranes, ribosomes, and DNA

NEET favourite: ribosomes are the ONLY organelle in a prokaryotic cell — and they are 70S (50S large + 30S small subunit), while eukaryotic cytoplasmic ribosomes are 80S (60S + 40S)

Prokaryotes have NO nuclear membrane, NO nucleolus and NO membrane-bound organelles — the nucleoid is a naked, single, circular DNA region (no histones in true bacteria), not a true nucleus

Mesosome (an infolding of the plasma membrane) is UNIQUE to prokaryotes — it aids respiration, secretion, DNA replication and cell division (and is a frequent NCERT-line MCQ)

Trap: mitochondria and chloroplasts of eukaryotes carry 70S ribosomes and circular DNA — the endosymbiotic link that NEET loves to test inside a eukaryotic cell

How much this is worth in the exam

Cell: The Unit of Life is a high-yield NEET chapter (~2–3 questions/year), and the prokaryote-vs-eukaryote contrast is its anchor concept. NCERT phrases most of these as "which of the following is/are found ONLY in prokaryotes" assertion-reason items, so the exceptions below matter more than the basic table.

The exception examiners exploit

Eukaryotic cells contain 80S cytoplasmic ribosomes — BUT their mitochondria and chloroplasts contain 70S ribosomes (evidence for the endosymbiotic theory). So "all ribosomes in a eukaryote are 80S" is FALSE. This single exception is one of NEET's most repeated traps.

The four exceptions NEET tests most

The plain table says "prokaryote = X, eukaryote = Y". NEET scores its marks on the cases where that breaks down. Memorise these.

Feature	The "rule"	The exception NEET asks
Ribosomes	Pro = 70S, Euk = 80S	Mitochondria & chloroplasts (in eukaryotes) have 70S
Membrane-bound organelles	Only in eukaryotes	Mesosome (infolded membrane) is the prokaryotic analogue; cyanobacteria have thylakoid-like membranes
Histones / chromosomes	Histones only in eukaryotes	Archaea (a prokaryote) have histone-like proteins
Cell wall material	Pro = peptidoglycan	Archaea LACK peptidoglycan; plant walls are cellulose, fungal are chitin

Common mistakes students make

"Prokaryotes have no internal membranes at all."

Prokaryotes lack membrane-bound ORGANELLES, but they do have membrane infoldings — the mesosome (helps in respiration, DNA replication, cell-wall formation) and, in cyanobacteria, photosynthetic membranes.

"Viruses are the simplest prokaryotes."

Viruses are not cells at all (acellular) — they have no ribosomes, no cytoplasm, and cannot self-replicate. They are neither prokaryotic nor eukaryotic.

Exam Relevance

This topic falls under Cell Structure in Biology for NEET. Questions on the difference between prokaryotic cell and eukaryotic cell appear frequently in competitive exams, both as direct MCQs and as part of numerical/assertion-reason problems.

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