12 Questions
Protein digestion begins in the small intestine.
False
The primary enzyme involved in proteolytic digestion is trypsin.
False
Trypsin cleaves peptide chains mainly at the amino side of the amino acids lysine or arginine.
False
Chymotrypsin preferentially catalyzes the hydrolysis of peptide bonds involving alanine and glycine.
False
Elastase breaks down proteins into free amino acids only.
False
Digested proteins are released into the lymphatic system.
False
The stomach's highly acidic environment is necessary for protein digestion.
True
Pepsin catalyzes the hydrolysis of peptide bonds at an optimal pH of 7.
False
Trypsin cleaves peptide chains mainly at the carboxyl side of the amino acids lysine or arginine.
False
Chymotrypsin prefers small hydrophobic residues.
False
Proteolytic enzymes break down proteins into free amino acids only.
False
Dipeptides and tripeptides are absorbed by the intestinal mucosa cells and released into the lymphatic system.
False
Study Notes
Protein Digestion
- Protein digestion begins in the stomach, where the highly acidic environment denatures proteins, making them susceptible to proteolytic digestion.
- The primary enzyme involved in proteolytic digestion is pepsin, which catalyzes the nonspecific hydrolysis of peptide bonds at an optimal pH of 2.
Pancreatic Enzymes in Proteolytic Digestion
- In the small intestine, the pancreas secretes zymogens of trypsin, chymotrypsin, elastase, and other enzymes.
- Trypsin cleaves peptide chains mainly at the carboxyl side of lysine or arginine, except when either is followed by proline.
- Chymotrypsin prefers large hydrophobic residues and preferentially catalyzes the hydrolysis of peptide bonds involving tyrosine, phenylalanine, and tryptophan.
Absorption of Amino Acids and Peptides
- Proteolytic enzymes break down proteins into free amino acids, dipeptides, and tripeptides.
- These are absorbed by intestinal mucosa cells and subsequently released into the bloodstream, where they are absorbed by other tissues.
Protein Digestion
- Protein digestion begins in the stomach, where the highly acidic environment denatures proteins, making them susceptible to proteolytic digestion.
- The primary enzyme involved in proteolytic digestion is pepsin, which catalyzes the nonspecific hydrolysis of peptide bonds at an optimal pH of 2.
Pancreatic Enzymes in Proteolytic Digestion
- In the small intestine, the pancreas secretes zymogens of trypsin, chymotrypsin, elastase, and other enzymes.
- Trypsin cleaves peptide chains mainly at the carboxyl side of lysine or arginine, except when either is followed by proline.
- Chymotrypsin prefers large hydrophobic residues and preferentially catalyzes the hydrolysis of peptide bonds involving tyrosine, phenylalanine, and tryptophan.
Absorption of Amino Acids and Peptides
- Proteolytic enzymes break down proteins into free amino acids, dipeptides, and tripeptides.
- These are absorbed by intestinal mucosa cells and subsequently released into the bloodstream, where they are absorbed by other tissues.
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