Which type of reaction involves the removal of an amino group from an amino acid?

The correct answer is based on the definition of deamination, which refers specifically to the biochemical process that involves the removal of an amino group from an amino acid. During deamination, the amino group (-NH2) is released, often resulting in the formation of ammonia (NH3) and a corresponding keto acid. This reaction is crucial for amino acid catabolism, allowing the body to utilize amino acids for energy production or to convert them into other compounds.

In contrast, the other processes listed play different roles in biochemical reactions. Dehydration synthesis refers to the formation of larger molecules from smaller ones while releasing water, which is not related to the removal of an amino group. Hydrolysis involves the addition of water to break down compounds, again not dealing with the removal of an amino group. Transamination is the transfer of an amino group from one amino acid to a keto acid, resulting in the formation of a new amino acid and a new keto acid, which is distinct from the process of deamination. Thus, the specificity of the term deamination makes it the correct choice for this question.