Question

Correct sequence of chemical entities involved in nucleic acid synthesis in bacteria is:

• A. B, A, C, D
• B. A, C, B, D
• C. A, D, C, B
• D. A, B, D, C

Hint:

Remember: PABA $\rightarrow$ Dihydro $\rightarrow$ Tetrahydro $\rightarrow$ DNA. Sulfonamides block the first step!

Answer 1

The Correct Option is B

Step 1: Concept
Bacteria synthesize folic acid de novo, which is essential for the synthesis of purines and thymidine, the building blocks of DNA.

Step 2: Meaning
The pathway converts simple precursors into complex nucleic acids through specific enzymatic steps.

Step 3: Analysis
The sequence begins with Para-amino benzoic acid (PABA) (A). This is converted into Dihydrofolate (C) , which is then reduced to Tetrahydrofolate (B). Tetrahydrofolate acts as a co-factor to eventually synthesize DNA (D).

Step 4: Conclusion
The correct biochemical order is A $\rightarrow$ C $\rightarrow$ B $\rightarrow$ D.

Final Answer: (B)