Prokaryotic Cells — NEET Biology MCQs with Solutions
Free NEET Biology Prokaryotic Cells MCQs with step-by-step solutions (81 questions). Part of Cell: The Unit of Life. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Prokaryotic Cells · easy · theory
A defining feature of prokaryotic cells is the absence of a:
A. Ribosomes
B. Membrane-bound nucleus and organelles ✓ Correct
C. Cytoplasm
D. Cell membrane
Solution: Prokaryotes lack a nuclear envelope and membrane-bound organelles; their DNA lies in a nucleoid.
Q2 — Prokaryotic Cells · easy · theory
The ribosomes of prokaryotes are of the ______ type:
A. 60S
B. 70S ✓ Correct
C. 80S
D. 90S
Solution: Prokaryotic ribosomes are 70S (30S + 50S); eukaryotic cytoplasmic ribosomes are 80S.
Q3 — Prokaryotic Cells · medium · theory
Extra-chromosomal, small circular DNA in bacteria that carries genes (e.g. for resistance) is the:
A. Inclusion body
B. Plasmid ✓ Correct
C. Nucleoid
D. Mesosome
Solution: Plasmids replicate independently and often carry antibiotic-resistance genes; they are used as cloning vectors.
Q4 — Prokaryotic Cells · medium · theory
The infolding of the plasma membrane in bacteria that helps in respiration, DNA replication and cell wall formation is the:
A. Mesosome ✓ Correct
B. Lysosome
C. Golgi body
D. Endoplasmic reticulum
Solution: Mesosomes are membrane infoldings (analogous roles to some organelles); prokaryotes lack ER, Golgi, mitochondria.
Q5 — Prokaryotic Cells · hard · theory
The bacterial cell envelope (from outside in) consists of:
A. Only a plasma membrane
B. Cell wall and nuclear membrane
C. Glycocalyx, cell wall, and plasma membrane ✓ Correct
D. Capsule and mitochondria
Solution: The three-layered envelope is glycocalyx (capsule/slime) → cell wall (peptidoglycan) → plasma membrane.
Q6 — Prokaryotic Cells · hard · theory
Gram-positive and Gram-negative bacteria are distinguished on the basis of:
A. Ribosome type
B. Their cell wall structure (response to Gram staining) ✓ Correct
C. The presence of a nucleus
D. The presence of mitochondria
Solution: Gram staining differentiates thick peptidoglycan walls (Gram +) from thin walls with an outer membrane (Gram −).
Q7 — Prokaryotic Cells · easy · numerical
The genetic material of a bacterial cell is best described as:
A. Several linear DNA molecules wrapped around histones inside a nuclear envelope
B. A single naked, circular DNA molecule lying in the nucleoid, not enclosed by a membrane ✓ Correct
C. Circular DNA enclosed within a true membrane-bound nucleus
D. RNA associated with the mesosome
Solution: Prokaryotes have a single circular naked DNA (no histone-based nucleosomes, no nuclear membrane) located in the nucleoid region.
Q8 — Prokaryotic Cells · easy · numerical
Which structure gives certain bacterial cells the ability to adhere to surfaces or to host cells but is NOT involved in motility?
A. Pili and fimbriae ✓ Correct
B. Flagellum
C. Mesosome
D. Ribosome
Solution: Pili and fimbriae are small surface appendages used for attachment (and conjugation), not locomotion; the flagellum is the motility structure.
Q9 — Prokaryotic Cells · easy · numerical
Reserve materials in prokaryotic cells such as phosphate granules, glycogen granules and cyanophycean granules are stored as:
A. Granules enclosed within the nucleoid
B. Inclusion bodies lying free in the cytoplasm without any bounding membrane ✓ Correct
C. Vacuoles bounded by a tonoplast
D. Membrane-bound vesicles budded from the Golgi
Solution: Inclusion bodies store reserve material and lie freely in the cytoplasm, not enclosed by any membrane.
Q10 — Prokaryotic Cells · medium · numerical
A bacterium loses its ability to form a proper septum during division and cannot replicate its DNA efficiently. Damage to which membrane-derived structure best explains this?
A. Glycocalyx
B. Cyanophycean granule
C. Mesosome ✓ Correct
D. Pilus
Solution: Mesosomes (infoldings of the plasma membrane) aid in cell wall/septum formation, DNA replication and its distribution to daughter cells, so their loss impairs these functions.
Q11 — Prokaryotic Cells · medium · numerical
A bacterium is treated so that its peptidoglycan wall is destroyed while it is kept in an isotonic medium; the naked cell that survives (a protoplast) shows that in intact bacteria the cell wall chiefly:
A. Prevents the cell from bursting and gives it shape and mechanical support ✓ Correct
B. Carries out ATP synthesis for the cell
C. Holds the circular DNA in place
D. Stores the reserve food of the cell
Solution: The rigid cell wall prevents osmotic lysis and determines shape; removed in an isotonic medium the cell survives as a fragile protoplast, showing the wall is protective/structural, not metabolic.
Q12 — Prokaryotic Cells · medium · numerical
Assertion (A): Prokaryotic ribosomes and eukaryotic organellar ribosomes are both 70S. Reason (R): The S in 70S refers to a sedimentation coefficient, which is not strictly additive.
A. Both A and R are true but R is unrelated to sedimentation
B. A is true but R is false
C. Both A and R are true and R is the correct explanation of the non-additivity mentioned ✓ Correct
D. A is false but R is true
Solution: Prokaryotes and the ribosomes of mitochondria/chloroplasts are 70S; the S (Svedberg) unit measures sedimentation during centrifugation and is not additive, which is why a 70S ribosome has 50S + 30S subunits.
Q13 — Prokaryotic Cells · medium · numerical
In the diagrammatic bacterial flagellum, the three main parts arranged from the point of attachment outward are:
A. Hook, filament and basal body
B. Basal body, hook and filament ✓ Correct
C. Axoneme, hook and filament
D. Filament, hook and basal body
Solution: A bacterial flagellum consists, from the cell outward, of the basal body (anchored in the envelope), the hook, and the long filament; axoneme is a feature of eukaryotic cilia/flagella.
Q14 — Prokaryotic Cells · medium
Where is the genetic material located in prokaryotes?
A. Enveloped by nuclear membrane
B. Nucleus
C. Naked in cytoplasm ✓ Correct
D. None of these
Solution: Prokaryotes lack a true membrane-bound nucleus. Their genetic material (a single circular DNA) lies naked in the cytoplasm in a region called the nucleoid, not enclosed by a nuclear membrane.
Q15 — Prokaryotic Cells · medium
What is the genomic DNA of bacteria?
A. Circular DNA ✓ Correct
B. ds DNA, linear
C. Both (a) and (b)
D. Single stranded DNA
Solution: The bacterial genome is a single, double-stranded, circular DNA molecule located in the nucleoid. It is not single stranded and not linear.
Q16 — Prokaryotic Cells · medium
What are plasmids?
A. Enveloped DNA
B. None of these
C. Smaller DNA than genomic DNA ✓ Correct
D. Naked genomic DNA
Solution: Plasmids are small, circular, extrachromosomal DNA molecules that are smaller than the genomic DNA. They replicate independently and confer certain phenotypic traits such as antibiotic resistance.
Q17 — Prokaryotic Cells · medium
Resistance to antibiotics is conferred by
A. None of these
B. Chromosome
C. Both (a) and (b)
D. Plasmid DNA ✓ Correct
Solution: Antibiotic resistance in bacteria is conferred by plasmid DNA, the small extrachromosomal DNA that gives unique phenotypic characters and is widely used in genetic engineering.
Q18 — Prokaryotic Cells · medium
What is a specialized differentiated form of cell membrane in prokaryotes?
A. Plasmid
B. Nucleosome
C. Mesosome ✓ Correct
D. All of these
Solution: The mesosome is a specialized differentiated form of the cell membrane formed by extensions (infoldings) into the cytoplasm. Plasmids are DNA and nucleosomes are chromatin structures of eukaryotes.
Q19 — Prokaryotic Cells · medium
Infoldings of the cell membrane in prokaryotes are called
A. Mesosomes ✓ Correct
B. None of these
C. Lysosomes
D. Both (a) and (b)
Solution: Mesosomes are formed by the infoldings (extensions) of the plasma membrane into the cytoplasm. Lysosomes are membrane-bound organelles of eukaryotic cells.
Q20 — Prokaryotic Cells · medium
What is external to the cell wall in a prokaryotic cell?
A. None of these
B. Plasma membrane
C. Glycocalyx layer ✓ Correct
D. Both (a) and (b)
Solution: In the cell envelope, the outermost layer is the glycocalyx, which lies external to the cell wall. The order from outside to inside is glycocalyx, cell wall, then plasma membrane.
Q21 — Prokaryotic Cells · hard
What is external to the plasma membrane in a prokaryotic cell like bacteria?
A. Glycocalyx layer
B. Both (a) and (b) ✓ Correct
C. None of these
D. Cell wall
Solution: The plasma membrane is the innermost layer of the cell envelope. External to it lie both the cell wall and, outermost, the glycocalyx layer, so both structures are external to the plasma membrane.
Q22 — Prokaryotic Cells · medium
What is the basis of classification of bacteria into Gram-positive or Gram-negative?
A. Cell wall ✓ Correct
B. All of these
C. Glycocalyx layer
D. Plasma membrane
Solution: Bacteria are classified as Gram-positive or Gram-negative based on differences in their cell wall, revealed by their response to Gram's staining procedure.
Q23 — Prokaryotic Cells · medium
A loose sheath of the glycocalyx layer is called
A. Slime layer ✓ Correct
B. Plasma membrane
C. Capsule
D. Cell wall
Solution: The glycocalyx may be a loose sheath called the slime layer, or a thick and tough layer called the capsule.
Q24 — Prokaryotic Cells · medium
What is a thick, tough layer of glycocalyx known as?
A. Cell envelope
B. Capsule ✓ Correct
C. Slime layer
D. Cell wall
Solution: When the glycocalyx is thick and tough it is called a capsule, whereas a loose sheath is called the slime layer.
Q25 — Prokaryotic Cells · medium
Which of the following is a form of mesosome?
A. Vesicles
B. All of these ✓ Correct
C. Lamellae
D. Tubules
Solution: Mesosomes are formed by extensions of the plasma membrane in the form of vesicles, tubules and lamellae. Hence all of these are forms of a mesosome.
Q26 — Prokaryotic Cells · medium
Which of the following helps in respiration, secretion processes and increasing the surface area for enzymatic content?
A. Glycocalyx layer
B. Mesosomes ✓ Correct
C. Cell wall
D. Plasma membrane
Solution: Mesosomes help in cell wall formation, DNA replication and its distribution to daughter cells, respiration, secretion processes, and increase the surface area of the plasma membrane and its enzymatic content.
Q27 — Prokaryotic Cells · medium
In which organisms are the pigment-containing chromatophores found?
A. Green algae
B. Algae
C. Cyanobacteria ✓ Correct
D. Amoeba
Solution: In some prokaryotes such as cyanobacteria, membranous extensions into the cytoplasm called chromatophores contain pigments for photosynthesis.
Q28 — Prokaryotic Cells · medium
A thin, filamentous extension from the cell wall required for bacterial motility is called ________.
A. Hook
B. Tail
C. Mesosome
D. Flagella ✓ Correct
Solution: Flagella are the thin, filamentous extensions from the cell wall responsible for the motility of bacteria. A flagellum consists of a filament, hook and basal body.
Q29 — Prokaryotic Cells · medium
Which of the following is not a part of a bacterial flagellum?
A. Hook
B. None ✓ Correct
C. Filament
D. Basal body
Solution: A bacterial flagellum is composed of three parts: the filament, the hook and the basal body. Since all three listed are parts of it, the correct choice is 'None'.
Q30 — Prokaryotic Cells · medium
Which of the following surface structures of bacteria do not take part in motility?
A. Flagella
B. Pili
C. Fimbriae
D. Both (b) and (c) ✓ Correct
Solution: Flagella are responsible for motility. Pili and fimbriae are surface structures that do not play a role in motility, so both pili and fimbriae are the answer.