Question

Which of the following is NOT correct for Z-DNA conformation?

• A. The backbone having zig-zag conformation
• B. Only one groove is observed
• C. It cannot form nucleosome
• D. Phosphate groups are far apart than that of B-DNA

Hint:

Z-DNA: left-handed helix, zig-zag backbone.
Has two grooves: major and minor.
Cannot form nucleosomes.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
DNA exists in different conformations.
Z-DNA is one of the alternative conformations.

Step 2: Key Formula or Approach:
No specific formula.
Need to know the characteristics of Z-DNA.

Step 3: Detailed Explanation:
Z-DNA has a zig-zag backbone conformation (A is correct).
Z-DNA has a narrow, deep major groove and a shallow minor groove.
It has two grooves, not one (B is incorrect).
Z-DNA cannot form nucleosomes (C is correct).
Phosphate groups are farther apart in Z-DNA than in B-DNA (D is correct).
Thus, the incorrect statement is that only one groove is observed.

Step 4: Final Answer:
The statement "Only one groove is observed" is NOT correct for Z-DNA.
Hence, the correct option is (B).