Question

Match List I with List II 

Choose the correct answer from the options given below: 
 

• A. A - II, B - III, C - IV, D - I
• B. A - II, B - I, C - IV, D - III
• C. A - III, B - IV, C - II, D - I
• D. A - III, B - II, C - IV, D - I

Hint:

Gram Negative = Outer Membrane present.
Lichen = Algae + Fungus.
Flavonoids = "Calling signal" for nitrogen-fixing bacteria.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks to match specific microbial cell components, symbiotic relationships, and biochemical signals with their corresponding biological contexts.

Step 2: Detailed Explanation:

• Pseudomureins (A-II): This is a major cell wall component of Archaebacteria (formerly grouped under Bacteria). It is chemically distinct from the "murein" (peptidoglycan) found in Eubacteria, as it lacks N-acetylmuramic acid and D-amino acids.

• Cell Outer Membrane (B-I): This is the defining structural feature of Gram-negative bacteria. It lies outside the thin peptidoglycan layer and contains lipopolysaccharides (LPS), providing an extra layer of protection and toxicity.

• Algae-fungus association (C-IV): This is the classic definition of a Lichen. The fungus (mycobiont) provides structure and protection, while the algae or cyanobacteria (photobiont) provides food through photosynthesis.

• Flavonoids (D-III): These are chemicals secreted by legume roots. They serve as a signal to compatible Rhizobium bacteria, leading to the induction of nodulation (nod) genes, which is the first step in forming nitrogen-fixing root nodules.
Final Answer:
The matching pairs are A-II, B-I, C-IV, and D-III. This matches option (B).