Question

Bases bind to the ___ of deoxyribose sugar. The sugar binds to the ____ of purines and the ____ of pyrimidines.

Phosphates bind to the _____ of deoxyribose sugar.
A) 1st carbon, 5th carbon, 3rd carbon
B) 5th carbon, 3rd carbon, 1st carbon
C) 2nd carbon, 4th carbon, 3rd carbon
D) 3rd carbon, 1st carbon, 5th carbon

Answer 1

In a DNA molecule, bases attach to the 1' carbon of deoxyribose sugar, purines connect to the 9' nitrogen, pyrimidines to the 1' nitrogen, and phosphate groups link to the 5' carbon of deoxyribose sugar.

Step-by-step explanation:

The sugar binds to the 9' nitrogen of purines (adenine and guanine) and the 1' nitrogen of pyrimidines (cytosine and thymine). Phosphates bind to the 5' carbon of deoxyribose sugar. Therefore, the correct answer to the student's question is that bases bind to the 1' carbon of deoxyribose sugar, the deoxyribose sugar binds to the 9' nitrogen of purines and the 1' nitrogen of pyrimidines, and phosphates bind to the 5' carbon of deoxyribose sugar.