MCQs on Cell Injury, Adaptation, Feedback Systems, and Cell Death. (GPAT, NIPER, AIIMS Pharmacist, Railway Pharmacist, SSC, ESIC, State Pharmacist & B.Pharm University Exams)

1. A typical feedback system consists of:

A. Receptor, control center, effector
B. Neuron, muscle, gland
C. Stimulus, hormone, enzyme
D. Cell, tissue, organ

Answer: A. Receptor, control center, effector

2. Which is the best example of a negative feedback mechanism?

A. Blood clotting
B. Parturition
C. Regulation of blood glucose by insulin
D. Oxytocin secretion during labor

Answer: C. Regulation of blood glucose by insulin

3. Positive feedback differs from negative feedback because it:

A. Opposes the initial stimulus
B. Amplifies the initial stimulus
C. Maintains homeostasis directly
D. Requires hormones only

Answer: B. Amplifies the initial stimulus

4. Which process operates through positive feedback?

A. Thermoregulation
B. Blood pressure regulation
C. Blood clotting cascade
D. Blood glucose regulation

Answer: C. Blood clotting cascade

Causes of Cellular Injury

5. The most common cause of cell injury is:

A. Infection
B. Ischemia and hypoxia
C. Autoimmunity
D. Radiation

Answer: B. Ischemia and hypoxia

6. Which of the following is NOT a cause of cellular injury?

A. Nutritional imbalance
B. Genetic defects
C. Homeostasis
D. Physical agents

Answer: C. Homeostasis

7. Ionizing radiation primarily damages cells by:

A. Increasing ATP synthesis
B. Generating free radicals
C. Activating ribosomes
D. Enhancing DNA repair

Answer: B. Generating free radicals

8. Carbon monoxide causes cell injury mainly by:

A. DNA mutation
B. Ribosomal inhibition
C. Tissue hypoxia
D. Protein synthesis

Answer: C. Tissue hypoxia

9. The earliest consequence of plasma membrane damage is:

A. DNA fragmentation
B. Loss of ionic homeostasis
C. Increased protein synthesis
D. Chromosome condensation

Answer: B. Loss of ionic homeostasis

10. Increased intracellular calcium following membrane injury activates:

A. ATP synthesis
B. Phospholipases and proteases
C. Ribosomes
D. DNA replication

Answer: B. Phospholipases and proteases

11. Free radicals damage cell membranes mainly through:

A. Glycolysis
B. Lipid peroxidation
C. Protein synthesis
D. Transcription

Answer: B. Lipid peroxidation

12. The most important consequence of mitochondrial injury is:

A. Increased ATP production
B. ATP depletion
C. Increased mitosis
D. Hyperplasia

Answer: B. ATP depletion

13. Opening of mitochondrial permeability transition pores results in:

A. Enhanced oxidative phosphorylation
B. Loss of membrane potential
C. Increased ATP generation
D. Ribosomal activation

Answer: B. Loss of membrane potential

14. Release of cytochrome c from mitochondria triggers:

A. Hypertrophy
B. Apoptosis
C. Hyperplasia
D. Metaplasia

Answer: B. Apoptosis

15. Detachment of ribosomes from the rough endoplasmic reticulum leads to:

A. Increased protein synthesis
B. Reduced protein synthesis
C. DNA damage
D. Cell division

Answer: B. Reduced protein synthesis

16. Ribosomal damage particularly affects the synthesis of:

A. Structural and secretory proteins
B. ATP
C. DNA
D. Lipids only

Answer: A. Structural and secretory proteins.

17. Pyknosis refers to:

A. Nuclear swelling
B. Nuclear shrinkage and chromatin condensation
C. Nuclear fragmentation
D. Nuclear dissolution

Answer: B. Nuclear shrinkage and chromatin condensation

18. Fragmentation of the nucleus is known as:

A. Karyolysis
B. Pyknosis
C. Karyorrhexis
D. Metaplasia

Answer: C. Karyorrhexis

19. Complete dissolution of the nucleus is called:

A. Karyolysis
B. Pyknosis
C. Karyorrhexis
D. Dysplasia

Answer: A. Karyolysis

Cellular Adaptations

20. A decrease in cell size is termed:

A. Atrophy
B. Hypertrophy
C. Hyperplasia
D. Dysplasia

Answer: A. Atrophy

21. An increase in cell size without an increase in cell number is

A. Hyperplasia
B. Dysplasia
C. Hypertrophy
D. Metaplasia

Answer: C. Hypertrophy

22. Enlargement of skeletal muscles after exercise is an example of:

A. Hyperplasia
B. Hypertrophy
C. Metaplasia
D. Dysplasia

Answer: B. Hypertrophy

23. Increase in the number of cells is called:

A. Hyperplasia
B. Hypertrophy
C. Atrophy
D. Metaplasia

Answer: A. Hyperplasia

24. Which adaptation occurs in the endometrium during the menstrual cycle?

A. Atrophy
B. Hyperplasia
C. Dysplasia
D. Necrosis

Answer: B. Hyperplasia

25. Replacement of one mature cell type by another mature cell type is:

A. Dysplasia
B. Hyperplasia
C. Metaplasia
D. Neoplasia

Answer: C. Metaplasia

26. Squamous metaplasia commonly occurs in:

A. Smokers' bronchi
B. Liver
C. Heart
D. Kidney glomeruli

Answer: A. Smokers' bronchi

27. Dysplasia is characterized by:

A. Increased cell size only
B. Abnormal cellular growth and maturation
C. Cell death
D. Cell swelling

Answer: B. Abnormal cellular growth and maturation

28. Dysplasia is considered:

A. Always reversible normal adaptation
B. Potentially precancerous lesion
C. Cell death
D. Physiological adaptation

Answer: B. Potentially precancerous lesion

29. Cell swelling is the hallmark of:

A. Irreversible injury
B. Reversible injury
C. Hyperplasia
D. Apoptosis

Answer: B. Reversible injury

30. Cell swelling primarily results from:

A. Increased ATP production
B. Failure of Na⁺/K⁺ pump
C. Increased protein synthesis
D. DNA replication

Answer: B. Failure of Na⁺/K⁺ pump

31. Hydropic change is another term for:

A. Necrosis
B. Cell swelling
C. Hyperplasia
D. Metaplasia

Answer: B. Cell swelling

Intracellular Accumulations

32. Fatty change (steatosis) most commonly affects the:

A. Brain
B. Liver
C. Bone
D. Cartilage

Answer: B. Liver

33. Accumulation of triglycerides within hepatocytes is called:

A. Amyloidosis
B. Steatosis
C. Calcification
D. Hypertrophy

Answer: B. Steatosis

34. Lipofuscin pigment is known as:

A. Wear-and-tear pigment
B. Bile pigment
C. Melanin
D. Hemosiderin

Answer: A. Wear-and-tear pigment

35. Hemosiderin accumulation indicates excess storage of:

A. Calcium
B. Iron
C. Lipids
D. Glycogen

Answer: B. Iron

Cell Death

36. Necrosis is characterized by:

A. Programmed cell death
B. Inflammation of surrounding tissue
C. Intact plasma membrane
D. Energy-dependent process

Answer: B. Inflammation of surrounding tissue

37. Apoptosis is:

A. Always pathological
B. Unregulated cell death
C. Programmed cell death
D. Accompanied by marked inflammation

Answer: C. Programmed cell death

38. Which feature distinguishes apoptosis from necrosis?

A. Cell swelling
B. Membrane rupture
C. Absence of inflammation
D. ATP depletion

Answer: C. Absence of inflammation

39. Caspases are primarily involved in:

A. Necrosis
B. Apoptosis
C. Hyperplasia
D. Hypertrophy

Answer: B. Apoptosis

40. Which type of necrosis is classically associated with tuberculosis?

A. Coagulative necrosis
B. Fat necrosis
C. Fibrinoid necrosis
D. Caseous necrosis

Answer: D. Caseous necrosis

GPAT/NIPER High-Level Concept Questions

41. The sequence of nuclear changes in necrosis is:

A. Karyolysis → Pyknosis → Karyorrhexis
B. Pyknosis → Karyorrhexis → Karyolysis
C. Karyorrhexis → Pyknosis → Karyolysis
D. Pyknosis → Karyolysis → Karyorrhexis

Answer: B. Pyknosis → Karyorrhexis → Karyolysis

42. ATP depletion first affects:

A. DNA replication
B. Na⁺/K⁺ ATPase activity
C. Chromosome segregation
D. Cytokinesis

Answer: B. Na⁺/K⁺ ATPase activity

43. Which cellular adaptation may progress to malignancy if persistent?

A. Hypertrophy
B. Hyperplasia
C. Dysplasia
D. Atrophy

Answer: C. Dysplasia

44. Reversible cell injury is characterized by:

A. Membrane rupture
B. Massive calcium influx
C. Cell swelling and fatty change
D. Nuclear dissolution

Answer: C. Cell swelling and fatty change

45. The principal target of free radical injury in cell membranes is:

A. Cholesterol
B. DNA
C. Membrane lipids
D. Glycogen

Answer: C. Membrane lipids

Rapid Revision Pearls

• Negative feedback: Homeostasis.

• Positive feedback: Amplifies response (blood clotting, labor).

• Hypoxia/ischemia: The most common cause of cell injury.

• ATP depletion: Earliest biochemical event.

• Cell swelling: Reversible injury.

• Atrophy = ↓ cell size.

• Hypertrophy = ↑ cell size.

• Hyperplasia = ↑ cell number.

• Metaplasia = Replacement of one mature cell type by another.

• Dysplasia = Disordered growth; precancerous.

• Pyknosis, karyorrhexis, and karyolysis.

• Necrosis: Inflammation present.

• Apoptosis: Caspase-mediated, no inflammation.

• Caseous necrosis: Tuberculosis.

• Cytochrome c release: Apoptosis.