Final answer:
The alpha carbon in amino acids is the central carbon atom connected to an amino group, a carboxyl group, a hydrogen atom, and a side chain. Alpha amino acids are the building blocks of proteins, forming the primary structure through peptide bonds between their carboxyl and amino groups.
Step-by-step explanation:
The alpha (α) and beta (β) carbon are terms used within organic chemistry to describe the position of carbon atoms in relation to a functional group in a molecule. Regarding the question on alpha and beta carbon and their differences, alpha and beta refer to the relative positions of carbon atoms in molecules like amino acids and carbohydrates.
In the context of amino acids, the alpha carbon is the central carbon atom to which an amino group, a carboxyl group, a hydrogen atom, and a variable side chain are all attached. This is the definition of an alpha-amino acid. For example, alanine is an alpha-amino acid because both the amine (-NH₂) group and the carboxylic acid (-COOH) group are attached to the same central (alpha) carbon atom. The side chain, which differs among amino acids and determines their unique properties, is also connected to the alpha carbon. Therefore, the correct answer is option d) proteins; peptide bonds.
Proteins are made up of polypeptides, which are linear chains of alpha amino acids linked by peptide bonds. These peptide bonds form between the carboxyl group of one amino acid and the amino group of another, connecting them in a specific sequence to form the protein's primary structure. Different amino acids have side chains with varying properties that affect the protein's overall structure and function, leading to diverse protein functions.