Which process allows an amino acid to enter metabolic pathways?

Transamination is the process that facilitates the entry of amino acids into metabolic pathways. It involves the transfer of an amino group from an amino acid to a keto acid, thus forming a new amino acid and a new keto acid. This reaction is crucial because it helps convert amino acids into intermediates that can be directly integrated into various metabolic pathways, such as those involved in energy production and the synthesis of other molecules.

Amino acids are not directly involved in glycolysis, which primarily focuses on the breakdown of glucose for energy. The citric acid cycle is a critical step in cellular respiration but typically operates on acetyl-CoA and does not directly incorporate amino acids. Oxidative phosphorylation is the final stage of ATP production involving electron transport and does not pertain to the metabolic entry of amino acids. Instead, transamination bridges amino acid metabolism with other metabolic processes, making it essential for the utilization of amino acids in energy production and other biosynthetic pathways.