Question

Which of the following represents double stranded helix structure of DNA?

• A.
• B.
• C.
• D.

Hint:

Remember, accurate base pairing is crucial for DNA replication and transcription processes, ensuring genetic fidelity across generations.

Answer 1

The Correct Option is B

Step 1: Review base pairing rules.

In DNA, adenine (A) always pairs with thymine (T), and guanine (G) always pairs with cytosine (C). This is known as complementary base pairing, which is essential for the stability of the DNA double helix.

Step 2: Analyze the provided diagrams.

Option (1) and (3) display incorrect or non-standard base pairing, not consistent with the Watson-Crick model of DNA.

Option (4) represents RNA pairings, which involve uracil instead of thymine.

Conclusion: Only option (2) accurately represents the double-stranded helix structure of DNA with correct base pairings.

Answer 2

To solve this problem, we need to identify which of the given diagrams represents the double-stranded helix structure of DNA.

1. Double-Stranded Helix of DNA:
The structure of DNA is a double helix, where two strands are coiled around each other. Each strand is composed of nucleotides, and the nucleotides consist of a sugar, a phosphate group, and a nitrogenous base (A, T, C, G). The two strands are held together by hydrogen bonds between complementary base pairs: Adenine (A) pairs with Thymine (T), and Cytosine (C) pairs with Guanine (G).

2. Analyzing the Options:
We need to identify the diagram that correctly represents this structure:

• Option 1: This option shows a structure with complementary base pairing (A with T, C with G), which is the correct representation of the double-stranded helix of DNA.
• Option 2: This option has incorrect base pairing, where G pairs with T, which does not follow the rules of DNA base pairing.
• Option 3: This option has incorrect base pairing as well, and does not represent the double helix structure accurately.

3. Conclusion:
The correct representation of the double-stranded helix structure of DNA is shown in Option 1, where the base pairs are correctly aligned (A with T and C with G).

Final Answer:
The correct answer is Option B.