Final answer:
Pepsin starts the protein digestion process by breaking down proteins into smaller segments called polypeptides, which then are further digested in the small intestine to form amino acids. The correct option is 2) Polypeptides
Step-by-step explanation:
Protein Digestion and the Role of Pepsin
The digestion of proteins begins in the stomach, where it is facilitated by the enzyme pepsin in the presence of hydrochloric acid (HCl).
Pepsin is responsible for breaking down intact proteins into smaller segments known as polypeptides. These polypeptides are then transported to the small intestine, where other enzymes, such as trypsin and chymotrypsin that are secreted by the pancreas, continue the digestion process.
Ultimately, proteins are broken down into their constituent amino acids, but it is important to note that the initial action of pepsin results in the formation of polypeptides, not single amino acids.
In summary, pepsin starts to break protein molecules apart into polypeptides, not amino acids. Additional enzymes such as carboxypeptidase, dipeptidase, and aminopeptidase, which are found in the small intestine, complete the breakdown into single amino acids, which can be absorbed into the bloodstream. The correct option is 2) Polypeptides