Question

Select the correct pair of labelled structure of the partial RNA strand.

• 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

RNA is the polymer of ribonucleotides each of which has a ribose sugar (II), a nitrogenous base (III) and phosphate (I) group. The base of a nucleotide is joined covalently (at N-1 of pyrimidines and N-9 of purines) in an N –beta- glycosyl bond to the 1’ carbon of ribose sugar. The phosphate is esterified to the 5’ carbon. Thus, the correct answer is option A.