Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).

Assertion (A): A series of cellulolytic enzymes are employed in the wood degradation process by brown rot fungi.

Reason (R): Lignin is not degraded by these fungi, therefore, it has typical brown colour wood remains.

In light of the above statements, choose the most appropriate answer from the options given below.

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

Hint:

Compare brown rot and white rot fungi in terms of which wood component each can break down.

Answer 1

The Correct Option is A

Step 1: Brown rot fungi break down wood using a set of cellulolytic and hemicellulolytic enzymes that attack the carbohydrate part of wood, confirming Assertion (A).
Step 2: These fungi lack the enzyme system needed to break lignin, so lignin is left behind largely unchanged, and this leftover lignin gives the decayed wood its brittle, brown, cracked appearance, confirming Reason (R) and explaining why (A) happens.
Step 3: Since (R) correctly accounts for the mechanism in (A), the answer is option 1.