Question
3. (a) A food contains protein in as much detail as you can, what happens to this protein after the food is swallowed.
Answer
4
(231 Votes)
Lucas
Veteran · Tutor for 12 years
Answer
Protein is digested in the stomach via hydrochloric acid and pepsin, which break down into peptides. Then, in the small intestine, these peptides are broken down into smaller peptides by enzymes, including trypsin and chymotrypsin secreted by pancreas. Finally, the smallest unit of protein, amino acids, are absorbed into the bloodstream through active transport in the small intestine and utilized in the body for energy and new protein synthesis.
Explanation
When protein-rich food is consumed, it undergoes a complex digestion process in order to be absorbed by our body efficiently and put it into use. As chewed food enters esophagus, the muscles contract to push it into the stomach for further digestion.Once swallowed, the protein rich food enters the stomach where it meets the stomach's gastric juices that consist of hydrochloric acid and gastric protease enzyme called pepsin. Hydrochloric acid unravels proteins that have been wound into complex shapes, So, pepsin can act on it. Pepsin assists in breaking down the protein into smaller subunits known as peptides or polypeptides. This stage of protein digestion in the stomach is largely an acid-driven process. After the acidic stomach, the semi-digested food enters the small intestine which is less acidic and requires enzyme-driven protein digestion. Here, the polypeptides are acted upon by various enzymes like Trypsin and Chymotrypsin that are secreted by the pancreas. These enzymes help in breaking down the large peptides into smaller peptides.Also, the cells of small intestine secrete enzymes called peptidases. Carboxypeptidase, aminopeptidase and dipeptidase are the most important peptidases which act on small peptides to yield individual amino acids.Amino acids are the smallest unit of a protein and these then get absorbed into the bloodstream by absorptive epithelial cells through process of active transport in the small intestine and then circulated in the body for at the cellular level for various metabolic activities like synthesis of new proteins, Energy production, etc.