Answer:
1. Pepsin is the active form of a digestive enzyme in the stomach that breaks polypeptide chains into smaller peptide strands.
2. The cleavage of stomach results in formation of pepsinogen (which is a protein digesting enzyme found is gastric juice secreted by gastric glands present in the walls of stomach) which gets broken down into its active form i.e. pepsin in the stomach by the action of hydrochloric acid.
3. An amino acid chain made up of three amino acids joined together is called a tripeptide. (correct)
4. Dipeptide describes an amino acid chain made up of two amino acids joined together. (correct)
5. The 20 different amino acids are the building blocks used for protein synthesis. (correct)
6. Amino acid pools are stockpiles found in the blood and other cells of the body that can be used to build new proteins. (correct)
7. The continual process of degrading and synthesizing protein is called protein turnover. (correct)
8. The stomach produces pepsin, which denatures protein. (correct)
9. Denaturation occurs when a protein is exposed to heat, acid, bases, or mechanical agitation resulting in unfolding of the protein, though the peptide bonds remain intact. (correct)
10. The part of an amino acid that contains nitrogen is called the amine group. (correct)
11. The acid group is also known as the hydroxyl group.
12. Single amino acids that are absorbed in the small intestine travel to the liver via the portal vein. (correct). The portal vein is also called hepatic portal.