What is the definition of acetylation?

• A. Introduction of a hydroxyl group to a compound
• B. Addition of an acyl group to a molecule
• C. Introduction of an acetyl group to an organic compound
• D. Addition of a methyl group to an amine

Answer: (C)

Acetylation is defined as the introduction of an acetyl group to an organic compound. An acetyl group is a specific functional group with the structure -COCH₃, which consists of a carbonyl (C=O) and a methyl (CH₃) group. This modification plays a significant role in various biological processes, including the regulation of gene expression through the acetylation of histones, as well as influencing the activity of certain proteins and metabolic pathways.

The other definitions provided do not accurately describe acetylation. The introduction of a hydroxyl group pertains to a different functional group addition, while the addition of an acyl group is a broader definition that doesn't specifically refer to the acetyl group. Lastly, adding a methyl group to an amine addresses a distinct chemical modification known as methylation, which differs in structure and function from acetylation. Therefore, the description that aligns perfectly with the definition of acetylation is the introduction of an acetyl group to an organic compound.