Question

Which one of the following is not applicable to RNA?

• A. Chargaff’s rule
• B. 5′ phosphoryl and 3′ hydroxyl ends
• C. Heterocyclic nitrogenous bases
• D. Complementary base pairing

Answer 1

The correct option is A

Chargaff’s rule

The correct option is A.

The explanation for the correct option :

1. The ratio of pyrimidine and purine nucleotides in DNA in any organism's cell is 1:1.
2. The amount of guanine should be equal to cytosine, and the amount of adenine should be equal to thymine, according to this rule.
3. It can be used with two-stranded molecules like DNA.
4. As a result, this rule holds true for DNA as well as some double-stranded RNA.

The explanation for the incorrect option :

Option B:

1. Those are called as complementary base pairs.
2. In RNA, a 2' hydroxyl end is present and in DNA, a 3' hydroxyl end is present.

Option C:

1. A ring complex has more than two types of atoms.
2. Uracil, thymine, adenine, guanine, and cytosine are examples of heterocyclic nitrogenous bases.
3. DNA and RNA are two different types of genetic components.
4. Deoxyribose contains one less oxygen than ribose sugar, thus although DNA contains thymine, RNA contains uracil.

Option D:

1. There are five different forms of nitrogenous bases in genetic material.
2. Pyrimidine: -uracil, cytosine, and thymine and Purine -adenine and guanine.

Final Answer: Chargaff's rules are not applicable to RNA.