What are proteins?

Proteins are defined as large biomolecules or macromolecules that consist of one or more long chains of amino acids. These chains are interconnected by peptide bonds, and the sequence and composition of these amino acids determine the protein's unique structure and function. Proteins play a crucial role in numerous biological processes, including structural support, catalyzing biochemical reactions as enzymes, transporting molecules, and facilitating communication between cells.

The definition provided in the correct answer highlights the importance of amino acids as the building blocks of proteins. There are 20 different amino acids that can be combined in various sequences to form a wide diversity of proteins, each with specific roles within an organism. This understanding is fundamental in fields such as biochemistry, molecular biology, and genetics, as it provides insights into protein synthesis, function, and regulation.

In contrast, the other options incorrectly describe proteins. Some refer to sugars, which are carbohydrates, while others mention fatty acids or enzymes without accurately depicting what proteins actually are. Recognizing the distinct nature and function of proteins in comparison to other biomolecules is essential for a solid understanding of biological sciences.