Question

The correct statement with regard to the secondary structure of DNA/RNA is:

• A. DNA possesses a single strand helix structure and contains uracil as one of the four bases.
• B. DNA possesses a double strand helix structure and contains thymine as one of the four bases.
• C. RNA possesses a double strand helix structure and contains uracil as one of the four bases.
• D. RNA possesses a single strand helix structure and contains thymine as one of the four bases.

Hint:

DNA is double stranded and contains thymine, whereas RNA is usually single stranded and contains uracil.

Answer 1

The Correct Option is B

Step 1: Understand the structure of DNA.
DNA stands for deoxyribonucleic acid. The secondary structure of DNA is a double helical structure. This means DNA consists of two polynucleotide strands coiled around each other.

Step 2: Identify the bases present in DNA.
The four nitrogenous bases present in DNA are: \[ \text{Adenine, Guanine, Cytosine, Thymine} \] They are usually written as: \[ A,\ G,\ C,\ T \]

Step 3: Understand the structure of RNA.
RNA is generally single stranded. The four bases present in RNA are: \[ \text{Adenine, Guanine, Cytosine, Uracil} \] RNA contains uracil instead of thymine.

Step 4: Check the options.
Option (A) is incorrect because DNA is not single stranded and DNA does not contain uracil. Option (B) is correct because DNA has double helix structure and contains thymine. Option (C) is incorrect because RNA is usually single stranded, not double stranded. Option (D) is incorrect because RNA contains uracil, not thymine. Therefore, the correct statement is: \[ \text{DNA possesses a double strand helix structure and contains thymine.} \]