AP BIOLOGY

Detailed explanation-1: -Once a protein source reaches your stomach, hydrochloric acid and enzymes called proteases break it down into smaller chains of amino acids. Amino acids are joined together by peptides, which are broken by proteases. From your stomach, these smaller chains of amino acids move into your small intestine.

Detailed explanation-2: -Tripeptides, dipeptides, and single amino acids enter the enterocytes of the small intestine using active transport systems, which require ATP. Once inside, the tripeptides and dipeptides are all broken down to single amino acids, which are absorbed into the bloodstream.

Detailed explanation-3: -Enzymes in the stomach and small intestine break down proteins into amino acids.

Detailed explanation-4: -Of these five components, pepsin is the principal enzyme involved in protein digestion. It breaks down proteins into smaller peptides and amino acids that can be easily absorbed in the small intestine.

Detailed explanation-5: -From the Stomach to the Small Intestine The cells that line the small intestine release additional enzymes that finally break apart the smaller protein fragments into the individual amino acids. The muscle contractions of the small intestine mix and propel the digested proteins to the absorption sites.