Digestion and Absorption

• What does amylase do?

  Breaks down starch into maltose
• Where is amylase produced?

  Salivary glands and pancreas
• What enzyme breaks maltose into glucose?

  Maltase (a membrane-bound disaccharidase)
• What are the products of sucrase and lactase activity?

  • Sucrase: glucose + fructose
  • Lactase: glucose + galactose
• How is glucose absorbed into the blood?

  1. Co-transport with Na⁺ into epithelial cells
  2. Facilitated diffusion into capillaries
• What do endopeptidases do?

  Break internal peptide bonds in proteins
• What do exopeptidases do?

  Remove single amino acids from peptide ends
• What do dipeptidases do?

  Break dipeptides into two amino acids
• How are amino acids absorbed?

  • By co-transport with Na⁺ into epithelial cells
• What enzyme breaks down triglycerides into fatty acids and monoglycerides?

  Lipase
• What bonds does lipase break in a triglyceride molecule?

  Ester bonds
• What are micelles made of?

  Fatty acids, monoglycerides, and bile salts
• What is the role of micelles?

  Transport fatty acids and monoglycerides to epithelial cells
• How do fatty acids and monoglycerides cross the epithelial membrane?

  By simple diffusion—they are small and lipid-soluble
• What happens to fatty acids and monoglycerides inside the epithelial cell?

  They are reassembled into triglycerides
• What organelle packages triglycerides with proteins into chylomicrons?

  The Golgi apparatus
• What are chylomicrons?

  Vesicles containing triglycerides and proteins
• Why do chylomicrons enter the lymphatic system instead of blood capillaries?

  They are too large to enter the blood directly