Chapter 12, Problem 7A

Summary Introduction

Introduction :

The labeled diagram is of a nucleotide. A nucleotide is made a five-carbon sugar, a phosphate group, and a nitrogenous base. In the given diagram A represents a phosphate group, B is a pentose sugar and C is nitrogenous base and the D is a covalent bond.

Answer to Problem 7A

Correct answer :

The correct answer is option (C) C.

Explanation of Solution

Explanation/justification for the correct answer :

Option (C) C represents nitrogenous base. It is the nitrogenous base that determines a code. The sequence of 3 bases such AUG is makes one genetic code. Thus, this is the correct answer.

The explanation for the incorrect answer :

Option (A) A. A is the phosphate group, it does not form the genetic code. Thus, this is an incorrect option.

Option (B). B represents 5-carbon sugar that also does not form the genetic code. Thus, this is an incorrect answer.

Option (D) D. D represents the covalent bond between phosphate and pentose sugar that does not form the genetic code. Thus, this is an incorrect answer.