Q. 17.20 - An Introduction to General, Organic, and Biological Chemistry

Question

What component in a nucleic acid determines the $3\text{'}$ free end?

Step-by-Step Solution

Answer

The $3\text{'}$ free end of nucleic acid is determined by the free hydroxyl group (data-custom-editor="chemistry" $\mathrm{OH}$ group) on the $3\text{'}$ carbon of the sugar unit (ribose or deoxyribose).

Step 1 : Introduction

The objective is to determine what component in a nucleic acid in the $3\text{'}$ free end

Step 2 : Explanation

Nucleic acids are organic macromolecules that are present all over the cell. They were first discovered in the nuclei of cells. Nucleic acids, such as DNA and RNA, are found in all known forms of life. 

One of the components of nucleotide structure is nitrogen bases. Purines and pyrimidines are nitrogen bases that form various nucleotide structures.

Step 3 : Phosphate and sugar

The backbone structure of nucleic acid is made up of phosphate and sugar. Both DNA and RNA have a sugar-phosphate backbone that serves as a structural foundation. 

The $3\text{'}$ free end of nucleic acid is determined by the free hydroxyl group ($OH$ group) on the $3\text{'}$ carbon of the sugar unit (ribose or deoxyribose).