Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A) : Defective apoptotic processes have been implicated in a wide variety of diseases
Reason (R) : Excessive apoptosis causes atrophy whereas an insufficient amount results in cancer.
In light of the above statements, choose the correct answer from the options given below.

• A. Both (A) and (R) are true and (R) is the correct explanation of (A).
• B. Both (A) and (R) are true but (R) is NOT the correct explanation of (A).
• C. (A) is true but (R) is false.
• D. (A) is false but (R) is true.

Hint:

To test the causal link: "Defective apoptosis causes disease because too much apoptosis kills necessary cells (atrophy) and too little allows mutated cells to survive (cancer)." This is a perfect logical fit.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Apoptosis, or programmed cell death, is a highly regulated physiological process essential for maintaining tissue homeostasis, embryonic development, and removing damaged or potentially harmful cells.

Step 2: Detailed Explanation:
Let us analyze both statements:
- Assertion (A): Defective apoptotic processes (either excessive or insufficient cell death) are implicated in a wide variety of diseases across human and veterinary medicine. This statement is correct.
- Reason (R): The pathological consequences of abnormal apoptosis are dual-sided:
1. Excessive apoptosis leads to the premature or accelerated death of healthy cells, resulting in tissue loss or organ atrophy. This is observed in neurodegenerative disorders (e.g., canine cognitive dysfunction), ischemic injury, and acquired immunodeficiency syndromes.
2. Insufficient apoptosis allows cells that should normally be destroyed (such as those with DNA damage or mutations) to survive and proliferate unchecked. This survival directly contributes to neoplastic transformation, tumor development (cancer), and autoimmune diseases (where self-reactive lymphocytes fail to undergo clonal deletion). This statement is correct.
- Causal Link: Because excessive apoptosis causes tissue atrophy and insufficient apoptosis permits oncogenesis, any defect in this homeostatic process directly explains why defective apoptosis is implicated in such a wide variety of pathological diseases. Thus, (R) is the correct explanation of (A).

Step 3: Final Answer:
Both (A) and (R) are true and (R) is the correct explanation of (A), corresponding to option (A).