Question

which of the following chemical bonds is illustrated by the line in the diagram?
a the bond between the phosphate groups
b the peptide bonds between amino acids
c the bond between sugar and phosphate groups
d the hydrogen bonds between bases

Explanation:

The diagram appears to be of a DNA double helix. In DNA, the rungs of the helix are formed by hydrogen bonds between complementary nitrogenous bases (adenine - thymine, guanine - cytosine). Option A refers to bonds in the sugar - phosphate backbone (phosphodiester bonds), not the ones shown as the "line" (rungs). Option B is about peptide bonds (in proteins, between amino acids), not DNA. Option C is incorrect as sugar and phosphate are linked by phosphodiester bonds in the backbone. Option D correctly identifies the hydrogen bonds between the bases that form the rungs of the DNA helix.

Answer:

D. The hydrogen bonds between bases