Digestion and enzymes

• What is the pH of stomach acid?

  Approx pH 2
• What role does bile play in digestion?

  Bile emulsifies fats for better digestion
• What does lipase break down lipids into?

  Fatty acids and glycerol
• Where is lipase produced?

  In the pancreas
• What is the function of lacteals in the digestive system?

  Transport products of fat digestion to lymph
• How do villi aid in nutrient absorption?

  They increase surface area for absorption
• What is the approximate surface area of the small intestine?

  Approx 260 m²
• Why do villi have a good blood supply?

  To maximize nutrient absorption into blood
• What is the role of mitochondria in intestinal cells?

  Provide energy for active transport
• What is the thickness of the walls of villi?

  One cell thick
• What is the function of hydrochloric acid in the stomach?

  Provides optimum pH for pepsin
• What does pepsin break down?

  Proteins into peptides
• What is the role of bile in the duodenum?

  Neutralizes stomach acid and aids digestion
• What is the main enzyme for lipid digestion?

  Lipase
• What happens to enzymes when they are denatured?

  They become unstable and lose function
• How does mechanical digestion differ from chemical digestion?

  Mechanical digestion physically breaks down food
• What are the types of tissues in the human digestive system?

  • Muscular tissue: contracts and relaxes
  • Glandular tissue: produces enzymes and hormones
  • Epithelial tissue: covers body and organs
• What is the process of peristalsis?

  • Muscles in the alimentary canal contract and relax
  • Moves food (bolus) through the digestive system
• What factors affect enzyme action?

  • Temperature: affects enzyme activity
  • pH: changes active site stability
  • Denaturation: irreversible loss of function
• What is the digestion process of proteins?

  1. Pepsin in stomach breaks down proteins
  2. Trypsin in pancreas continues digestion
  3. Produces peptides and amino acids
• What is the digestion process of lipids?

  1. Lipase in pancreas breaks down lipids
  2. Produces fatty acids and glycerol
  3. Occurs in the small intestine