​The diffraction patterns of two forms of DNA (A and B) and statements related to these patterns are given below.​

A. The diffraction pattern corresponding to A-DNA is shown by form 1 with 11.6 base pairs per turn.

B. The diffraction pattern of B-DNA is shown by form 2 with 11.6 base pairs per turn.
C. The diffraction pattern of A-DNA is shown by form 2 with 11.6 base pairs per turn.
D. The diffraction pattern of B-DNA is shown by form 1 with 10 base pairs per turn.

Which one of the following options have all correct statements?

Correct option is A

Image Description Recap:

There are two forms of DNA shown via X-ray diffraction patterns:

• Form 1: Compact, tight pattern.

• Form 2: Cross-like, classic B-DNA pattern.

Understanding the Forms:

• A-DNA:

  • Appears in dry conditions.

  • Has ~11.6 base pairs per turn.

  • Its diffraction pattern is more compact and less cross-shaped — matches Form 2.

• B-DNA:

  • The most common form under physiological conditions.

  • Has ~10 base pairs per turn.

  • Its diffraction pattern has a characteristic “X” shape — matches Form 1.

Now, analyze each statement:

• Statement C:
  "The diffraction pattern of A-DNA is shown by form 2 with 11.6 base pairs per turn."
  Correct – A-DNA is associated with 11.6 bp/turn and matches form 2.

• Statement D:
  "The diffraction pattern of B-DNA is shown by form 1 with 10 base pairs per turn."
  Correct – B-DNA is associated with 10 bp/turn and matches form 1.

Final Answer:

Option: C and D are correct.