Question

From the given partial RNA strand, identify the correct options for the labels given in the picture.

• A. I- Phosphate; II- Ribose; III- Nitrogen base
• B. I- Phosphate; II- Nitrogen base; III- Ribose
• C. I- Nitrogen base; II- Phosphate; III- Ribose
• D. I- Ribose; II- Nitrogen base; III- Phosphate
• E. I- Ribose; II- Phosphate; III- Nitrogen base

Answer 1

The correct option is A I- Phosphate; II- Ribose; III- Nitrogen base

Ribonucleotide is the structural and functional unit of nucleic acids. Each ribonucleotide has sugar molecule (ribose), phosphate moiety and the nitrogenous base. The base of a ribonucleotide is joined covalently (at N-1 of pyrimidines and N-9 of purines) in an N –beta- glycosyl bond to the 1’ carbon of sugar. The phosphate is esterified to the 5’ carbon. Since phosphodiester bond links two ribose sugar via hydroxyl group of phosphate moiety, I is phosphate group and II is ribose sugar. III represents the nitrogenous base. Therefore, the correct answer is option A.