Part 8 — Complex & Application-Based NEET-Oriented Questions (Q176–200)

Part 8 — Cell: The Unit of Life – Complex & Application-Based NEET-Oriented Questions (Q176–200)

Q176.

Endosymbiotic theory is supported by which of the following?
A. Golgi apparatus & nucleus
B. Mitochondria & chloroplasts ✅
C. Lysosomes & vacuoles
D. Peroxisomes & ribosomes

Explanation:

• A. Not endosymbiotic origin.
• **B. Correct — both semi-autonomous, with circular DNA, 70S ribosomes.
• C. Formed from Golgi, not prokaryotic.
• D. Ribosomes aren’t organelles, peroxisomes arise differently.

Q177.

Which organelle malfunction is linked to Tay–Sachs disease?
A. Peroxisome
B. Lysosome ✅
C. Ribosome
D. Golgi

Explanation:

• A. Peroxisome disorders = Zellweger syndrome.
• **B. Correct — defective lysosomal enzymes cause accumulation of GM2 gangliosides.
• C. Ribosome → translation defects.
• D. Golgi not linked.

Q178.

A scientist isolates an organelle with double membrane, circular DNA, and 70S ribosomes. It is:
A. Nucleus
B. Mitochondrion or chloroplast ✅
C. Lysosome
D. Peroxisome

Explanation:

• A. Nucleus has linear DNA, histones.
• **B. Correct — both mitochondria & chloroplasts fit description.
• C. Lysosome = single membrane.
• D. Peroxisome = single membrane, no DNA.

Q179.

If Golgi apparatus is removed from a cell, which process is most directly affected?
A. DNA replication
B. Protein glycosylation & secretion ✅
C. Glycolysis
D. ATP synthesis

Explanation:

• A. DNA = nucleus.
• **B. Correct — Golgi modifies proteins, adds sugars, packages for secretion.
• C. Glycolysis = cytoplasm.
• D. ATP = mitochondria.

Q180.

Which organelle is absent in mature red blood cells?
A. Ribosome
B. Mitochondria
C. Nucleus
D. All of the above ✅

Explanation:

• A–C. All are absent in mature mammalian RBCs → space for hemoglobin.
• D. Correct.

Q181.

If nuclear pores are blocked, which of the following is immediately halted?
A. Export of mRNA ✅
B. Krebs cycle
C. Glycolysis
D. DNA replication

Explanation:

• **A. Correct — mRNA cannot leave → protein synthesis stops.
• B. Krebs = mitochondria.
• C. Glycolysis = cytoplasm.
• D. Replication occurs inside nucleus, unaffected directly.

Q182.

Which component of cytoskeleton helps in vesicle trafficking?
A. Intermediate filaments
B. Microtubules ✅
C. Actin filaments only
D. Collagen

Explanation:

• A. Provide strength, not transport.
• **B. Correct — kinesin/dynein move cargo on microtubules.
• C. Actin does local transport but main system = microtubules.
• D. Extracellular, not cytoskeleton.

Q183.

Which plastid transition occurs during leaf senescence (yellowing)?
A. Chloroplast → Chromoplast ✅
B. Chromoplast → Chloroplast
C. Amyloplast → Proteinoplast
D. Etioplast → Chloroplast

Explanation:

• **A. Correct — chlorophyll degrades, carotenoids dominate.
• **B. Reverse happens rarely.
• **C. Storage plastids, not pigments.
• **D. Etioplast → chloroplast in dark → light, not senescence.

Q184.

Which organelle produces hydrogen peroxide and also detoxifies it?
A. Mitochondria
B. Lysosome
C. Peroxisome ✅
D. Ribosome

Explanation:

• A. Mitochondria produce ROS, but not detoxify directly.
• B. Lysosome: hydrolytic enzymes.
• **C. Correct — peroxisomes have oxidases + catalase.
• D. Ribosome = translation.

Q185.

In photosynthetic eukaryotes, ATP is synthesized in:
A. Cytosol
B. Thylakoid membrane ✅
C. Cell wall
D. Nucleolus

Explanation:

• A. Glycolysis yields ATP in cytosol, but photosynthetic ATP is chloroplast-based.
• **B. Correct — photophosphorylation in thylakoid.
• C. Cell wall: no energy production.
• D. Nucleolus = rRNA.

Q186.

Which structure is analogous to plasmodesmata in animal cells?
A. Tight junction
B. Gap junction ✅
C. Desmosome
D. Glycocalyx

Explanation:

• A. Tight junction = barrier.
• **B. Correct — gap junctions = cytoplasmic communication channels.
• C. Adhesion only.
• D. Sugar coat, not channels.

Q187.

Which of the following organelles is NOT part of the endomembrane system?
A. ER
B. Golgi
C. Lysosome
D. Mitochondrion ✅

Explanation:

• A–C. All are part of endomembrane system.
• **D. Correct — mitochondria are semi-autonomous, not endomembrane.

Q188.

A prokaryotic cell lacks:
A. Plasma membrane
B. Ribosomes
C. Nucleoid
D. Membrane-bound nucleus ✅

Explanation:

• A. Plasma membrane present.
• B. Ribosomes present (70S).
• C. Nucleoid present.
• **D. Correct — no true nucleus.

Q189.

Which cytoskeletal element forms the cleavage furrow in cytokinesis?
A. Microtubules
B. Actin filaments ✅
C. Intermediate filaments
D. Collagen

Explanation:

• A. Spindle only.
• **B. Correct — actin + myosin contractile ring.
• C. Strength only.
• D. ECM protein.

Q190.

If chloroplast DNA is destroyed, which function is immediately affected?
A. ATP production in mitochondria
B. Synthesis of chloroplast proteins ✅
C. Glycolysis in cytosol
D. Nuclear DNA replication

Explanation:

• A. Mitochondria unaffected.
• **B. Correct — some chloroplast proteins coded by cpDNA.
• C. Glycolysis: cytoplasm.
• D. Nuclear DNA: independent.

Q191.

Which is true about eukaryotic chromatin?
A. Euchromatin = inactive, condensed
B. Heterochromatin = active, lightly stained
C. Euchromatin = active, lightly stained ✅
D. Chromatin has no proteins

Explanation:

• A & B. Reversed.
• **C. Correct — euchromatin is transcriptionally active.
• D. False, chromatin includes histones.

Q192.

If all lysosomes burst, which biomolecules will be digested first?
A. Only DNA
B. Only proteins
C. All biomolecules (carbs, lipids, proteins, nucleic acids) ✅
D. Only lipids

Explanation:

• A–B–D. Too narrow.
• **C. Correct — lysosomes contain hydrolytic enzymes for all biomolecules.

Q193.

If spindle fibers fail to attach to kinetochores, the cell will arrest at:
A. G1 phase
B. Metaphase ✅
C. Anaphase
D. Cytokinesis

Explanation:

• A. Before mitosis.
• **B. Correct — spindle assembly checkpoint halts progression until kinetochores attach.
• C. Occurs after successful attachment.
• D. Final step.

Q194.

Which structure is functionally equivalent to bacterial mesosomes in eukaryotes?
A. Golgi
B. Mitochondria ✅
C. Nucleolus
D. Vacuole

Explanation:

• A. Golgi: secretion.
• **B. Correct — mesosomes fold membrane for respiration, mitochondria serve same role in eukaryotes.
• C. Nucleolus: rRNA.
• D. Vacuole: storage.

Q195.

During cell division, spindle fibers attach to:
A. Centromere
B. Kinetochores ✅
C. Telomere
D. Centrosome

Explanation:

• A. Centromere holds chromatids, but fibers attach to kinetochores.
• **B. Correct — proteins at centromere region.
• C. Telomeres = ends of chromosomes.
• D. Centrosomes organize spindle, not attach.

Q196.

Which organelle is directly involved in β-oxidation of fatty acids?
A. Lysosome
B. Peroxisome ✅
C. Mitochondria
D. Ribosome

Explanation:

• A. Lysosome = digestion.
• **B. Correct — peroxisomes perform β-oxidation.
• C. Mitochondria also oxidize fatty acids, but initial detox in peroxisomes.
• D. Ribosome = translation.

Q197.

If smooth ER is destroyed, which synthesis is most affected?
A. Proteins
B. Lipids ✅
C. RNA
D. DNA

Explanation:

• **A. Proteins = RER.
• **B. Correct — SER synthesizes lipids/steroids.
• **C. RNA = nucleus.
• **D. DNA = nucleus.

Q198.

Which organelle is absent in animal cells but present in plant cells?
A. Golgi
B. Chloroplast ✅
C. Ribosome
D. Mitochondria

Explanation:

• **A. Golgi present in both.
• **B. Correct — chloroplast unique to plants/algae.
• C & D. Present in both.

Q199.

A mutation in dynein will primarily affect:
A. Flagellar movement ✅
B. DNA replication
C. ATP production
D. Transcription

Explanation:

• **A. Correct — dynein is the motor protein of cilia/flagella.
• B–D. Not affected directly.

Q200.

Which is the universal feature of all cells?
A. Nucleus
B. DNA as genetic material ✅
C. Chloroplasts
D. Mitochondria

Explanation:

• A. Only eukaryotes.
• **B. Correct — all cells (prokaryotic & eukaryotic) have DNA.
• C & D. Absent in prokaryotes.

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