Cell – Prokaryotic Cells: NEET MCQs with Answers

15 free questions on Cell – Prokaryotic Cells for NEET (UG), starting with previous-year NEET and AIPMT questions. Try each one, then tap Show answer for the answer and a short explanation.

Syllabus covered: Prokaryotic Cells

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Question 1

Previous-year question
What is the size of a Pleuropneumonia-like organism (PPLO)? [NEET (COVID-19) 2020]
  1. 0.02 μm
  2. 1-2 μm
  3. 10-20 μm
  4. 0.1 μm
Show answer
Answer: (D) 0.1 μm
Explanation: PPLO (Mycoplasma) are the smallest known cells, only about 0.1 μm in size. Typical bacteria are 1–2 μm, eukaryotic cells about 10–20 μm, and 0.02 μm is in the size range of viruses.

Question 2

Previous-year question
Which statement about inclusion bodies is INCORRECT? [NEET 2020]
  1. These are involved in the ingestion of food particles
  2. They lie free in the cytoplasm
  3. These represent reserve material in the cytoplasm
  4. They are not bound by any membrane
Show answer
Answer: (A) These are involved in the ingestion of food particles
Explanation: Inclusion bodies are non-membranous stores of reserve material such as glycogen, phosphate and cyanophycean granules; ingestion of food particles is not their function.

Question 3

Previous-year question
Which of the following terms is NOT correctly matched with its feature? [AIPMT 2015]
  1. Osmosis - movement of water by diffusion
  2. Nucleoplasm - site of active synthesis of ribosomal RNA
  3. Mesosome - infolding of cell membrane and characteristic of eukaryotes
  4. Pili - elongated tubular surface structures made of special protein in bacteria
Show answer
Answer: (C) Mesosome - infolding of cell membrane and characteristic of eukaryotes
Explanation: Mesosomes are indeed infoldings of the plasma membrane, but they are a characteristic of prokaryotes, not eukaryotes.

Question 4

Previous-year question
A protoplast is a cell [AIPMT 2015]
  1. without a nucleus
  2. undergoing division
  3. without a cell wall
  4. without a plasma membrane
Show answer
Answer: (C) without a cell wall
Explanation: A protoplast is the living part of a cell - protoplasm bounded by the plasma membrane - after the cell wall has been removed enzymatically; such protoplasts are widely used in somatic hybridisation.

Question 5

Previous-year question
Which one of the following is NOT an inclusion body found in prokaryotes? [AIPMT 2015]
  1. Cyanophycean granule
  2. Glycogen granule
  3. Polysome
  4. Phosphate granule
Show answer
Answer: (C) Polysome
Explanation: A polysome is an mRNA bearing several ribosomes and is engaged in protein synthesis. Inclusion bodies such as phosphate, cyanophycean and glycogen granules are reserve materials lying free in the cytoplasm.

Question 6

Previous-year question
Which of the following are NOT membrane-bound? [AIPMT 2015]
  1. Ribosomes
  2. Lysosomes
  3. Mesosomes
  4. Vacuoles
Show answer
Answer: (A) Ribosomes
Explanation: Ribosomes are naked, granular ribonucleoprotein particles with no limiting membrane; lysosomes, mesosomes and vacuoles are all membranous.

Question 7

Previous-year question
The cell wall is absent in [AIPMT 2015]
  1. Funaria
  2. Mycoplasma
  3. Nostoc
  4. Aspergillus
Show answer
Answer: (B) Mycoplasma
Explanation: Mycoplasma (PPLO) is the only prokaryote that has no cell wall, which is why it is pleomorphic and resistant to penicillin.
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Question 8

Previous-year question
Which structures perform the function of mitochondria in bacteria? [AIPMT 2014]
  1. Nucleoid
  2. Ribosomes
  3. Cell wall
  4. Mesosomes
Show answer
Answer: (D) Mesosomes
Explanation: Mesosomes bear the respiratory enzymes and electron transport chain on their membranes, thereby carrying out the function that mitochondria perform in eukaryotes.

Question 9

Previous-year question
The genophore, that is, the bacterial genome or nucleoid, is made of [AIPMT 1993]
  1. Histones and non-histones
  2. RNA and histones
  3. A single double-stranded DNA
  4. A single-stranded DNA
Show answer
Answer: (C) A single double-stranded DNA
Explanation: The genophore or nucleoid is composed of a single, circular, double-stranded DNA molecule. It is supercoiled with the help of RNA and polyamines, which together form a circular genetic material complex; histone proteins are absent.

Question 10

Previous-year question
The plasmid [AIPMT 1995]
  1. Helps in respiration
  2. Is a gene found inside the nucleus
  3. Is a component of the cell wall of bacteria
  4. Is genetic material additional to the main DNA in microorganisms
Show answer
Answer: (D) Is genetic material additional to the main DNA in microorganisms
Explanation: Plasmids are small, self-replicating, extrachromosomal and non-essential genetic elements found in bacteria. Each consists of a ring of circular, supercoiled, double-stranded DNA carrying genes for replication and for one or more non-essential cellular functions, and they are also called minichromosomes.

Question 11

Previous-year question
The site of respiration in bacteria is the [AIPMT 1997]
  1. Episome
  2. Mesosome
  3. Ribosome
  4. Microsome
Show answer
Answer: (B) Mesosome
Explanation: The cytoplasmic membrane of a bacterium is invaginated at certain places into the cytoplasm in the form of tubules called mesosomes. Enzymes associated with respiration are found on their surface, so the mesosome works as the mitochondrion of the bacterial cell.

Question 12

Previous-year question
Photosynthetic bacteria have their pigments in [AIPMT 1999]
  1. Leucoplasts
  2. Chloroplasts
  3. Chromoplasts
  4. Chromatophores
Show answer
Answer: (D) Chromatophores
Explanation: In photosynthetic bacteria the pigments are located in chromatophores, membranous vesicles derived from the plasma membrane. Bacteria have no plastids such as chloroplasts, chromoplasts or leucoplasts.

Question 13

Previous-year question
The main difference between Gram-positive and Gram-negative bacteria resides in their [AIPMT 2001]
  1. Cell wall
  2. Cell membrane
  3. Cytoplasm
  4. Flagella
Show answer
Answer: (A) Cell wall
Explanation: Gram staining is a differential stain whose basis lies in the lipid content and thickness of the bacterial cell wall. Gram-positive bacteria have a thick peptidoglycan wall and retain the crystal violet even after alcohol washing, whereas the wall of Gram-negative bacteria is thin and rich in lipids and is decolourised.

Question 14

Previous-year question
Chromosomes in a bacterial cell can be 1–3 in number and [AIPMT 2003]
  1. Can be circular as well as linear within the same cell
  2. Are always circular
  3. Are always linear
  4. Can be either circular or linear, but never both within the same cell
Show answer
Answer: (A) Can be circular as well as linear within the same cell
Explanation: Bacteria usually have one to three chromosomes. Most are circular, but some bacteria (e.g. Agrobacterium tumefaciens) have both a circular and a linear chromosome in the same cell.

Question 15

Previous-year question
Which one of the following also acts as a catalyst in a bacterial cell? [AIPMT 2011]
  1. snRNA
  2. hnRNA
  3. 23S rRNA
  4. 5S rRNA
Show answer
Answer: (C) 23S rRNA
Explanation: The 23S rRNA present in the large subunit of the 70S bacterial ribosome acts as a ribozyme, catalysing the formation of the peptide bond during translation. This peptidyl transferase activity is therefore due to RNA and not to a protein enzyme.

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