Question

In the polymerization of DNA, a phosphodiester bond is formed between a phosphate group of the nucleotide being added and which of the following atoms or molecules of the last nucleotide in the polymer? A. the 5' phosphate B. C6 C. the 3' OH D. a nitrogen from the nitrogen-containing base Reset Selection ▲ Question Progress ▲

Answer 1

C. 3´OH

Step-by-step explanation:

DNA is a large molecule built up by linking together smaller molecules called nucleotides.

A nucleotide contains a phosphate group, a sugar (deoxyribose in the case of DNA) and a nitrogen base.

The nucleotides are linked together by the binding of the phosphate group on carbon 5 in the nucleotide that is added, and the oxygen of the hydroxyl group (-OH) on carbon 3 of the last nucleotide of the DNA chain.

These bonds are called phosphodiester bonds and their formation releases a molecule of H2O.

This reaction is catalyzed by an enzyme, DNA polymerase, that requires a free 3´ hydroxyl group (3´ OH in the growing chain) to add the new nucleotide.