Question

A nucleic acid chain comprises of 
A. Phosphate group
B. Nitrogen base
C. Pentose sugar
D. Thiol group
E. $\beta$(1$\rightarrow$4) linkage
Choose the correct answer from the options given below:

• A. B and C only
• B. B, D and E only
• C. A, D and E only
• D. A, B and C only

Hint:

Remember the nucleotide structure: phosphate group + pentose sugar + nitrogenous base. No thiol groups or glycosidic linkages like $\beta$(1$\rightarrow$4) are involved in nucleic acids.

Answer 1

The Correct Option is D

Step 1: Understand the structure of a nucleic acid chain.
A nucleic acid chain (DNA or RNA) is a polymer made up of monomers called nucleotides. Each nucleotide consists of three essential components:
A phosphate group
A pentose sugar (ribose in RNA, deoxyribose in DNA)
A nitrogenous base (Adenine, Thymine, Cytosine, Guanine, or Uracil)
Step 2: Evaluate each given component.
A. Phosphate group – Yes, part of each nucleotide.
B. Nitrogen base – Yes, essential component of nucleotides.
C. Pentose sugar – Yes, forms the backbone with phosphate.
D. Thiol group – No, thiol groups (-SH) are found in some amino acids (like cysteine), not in nucleic acids.
E. $\beta$(1$\rightarrow$4) linkage – No, this glycosidic bond is found in polysaccharides like cellulose, not in nucleic acids.
Step 3: Select the correct set.
Only A, B, and C are correct components of a nucleic acid chain.