digestion and absorption

• What does digestion involve?

  Hydrolysis of large insoluble molecules
• What are the two types of enzymes mentioned for carbohydrate digestion?

  Amylase and membrane-bound disaccharidases
• Where is amylase produced?

  In the pancreas and salivary glands
• Where does carbohydrate digestion begin?

  In the mouth
• What does amylase do to carbohydrates?

  Hydrolyzes polysaccharides into disaccharides
• What is the first part of the small intestine called?

  Duodenum
• What do membrane-bound disaccharidases do?

  Hydrolyze disaccharides into monosaccharides
• What are endopeptidases responsible for?

  Hydrolyzing peptide bonds inside protein chains
• What do exopeptidases do?

  Hydrolyze peptide bonds at the ends of chains
• What are dipeptidases responsible for?

  Hydrolyzing peptide bonds between two amino acids
• Where does protein digestion start?

  In the stomach
• What enzyme is responsible for lipid digestion?

  Lipase
• What do bile salts do during lipid digestion?

  Emulsify lipids into smaller droplets
• Why is emulsification advantageous for digestion?

  It increases surface area for enzyme action
• How do fatty acids and monoglycerides enter epithelial cells?

  By diffusion through the plasma membrane
• What happens to fatty acids inside epithelial cells?

  They are reformed into triglycerides
• How do lipids eventually enter the bloodstream?

  Through the lymphatic system
• What are the key steps in the digestion of carbohydrates?

  1. Amylase hydrolyzes starch into disaccharides.
  2. Disaccharidases hydrolyze disaccharides into monosaccharides.
  3. Monosaccharides are absorbed into the bloodstream.
• What are the key steps in the digestion of proteins?

  1. Endopeptidases hydrolyze peptide bonds inside chains.
  2. Exopeptidases hydrolyze peptide bonds at the ends.
  3. Dipeptidases hydrolyze bonds between two amino acids.
• What are the key steps in the digestion of lipids?

  1. Bile salts emulsify lipids into small droplets.
  2. Lipase hydrolyzes triglycerides into fatty acids and glycerol.
  3. Fatty acids and monoglycerides form micelles for absorption.
• How does absorption occur in the ileum?

  • Villi increase surface area for absorption.
  • Microvilli further increase surface area.
  • Nutrients absorbed via co - transport or diffusion.