digestion and absorption

• What is the definition of digestion?

  Hydrolysis of large insoluble molecules
• What are the three types of molecules involved in digestion?

  Carbohydrates, lipids, and proteins
• What are the two enzymes mentioned for digestion?

  Amylases and membrane-bound disaccharidases
• What does the suffix "ase" indicate in biology?

  It indicates an enzyme
• Where is amylase produced?

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

  In the mouth
• What does amylase hydrolyze carbohydrates into?

  Disaccharides from polysaccharides
• What is the first part of the small intestine called?

  Duodenum
• What do membrane-bound disaccharidases do?

  Hydrolyze disaccharides into monosaccharides
• What do endopeptidases hydrolyze?

  Peptide bonds within the polymer chain
• What do exopeptidases hydrolyze?

  Peptide bonds at the ends of the polymer chain
• Where does protein digestion start?

  In the stomach
• What is the role of lipase in digestion?

  Hydrolyze ester bonds in triglycerides
• Where is lipase produced?

  In the pancreas
• What is the function of bile salts in lipid digestion?

  Emulsify lipids into tiny droplets
• Where are bile salts produced?

  In the liver
• What is the advantage of emulsifying lipids?

  Increases surface area for faster hydrolysis
• How does increased surface area affect lipase action?

  It allows more enzyme-substrate complexes
• What are micelles composed of?

  Fatty acids, monoglycerides, and bile salts
• How do micelles aid in absorption?

  Deliver fatty acids to epithelial cells
• Where does absorption primarily occur?

  In the ileum
• What structures increase the surface area for absorption in the ileum?

  Villi and microvilli
• What is the role of the capillary network in the villi?

  Maintains concentration gradient for absorption
• How are monosaccharides and amino acids absorbed?

  By co-transport and active transport
• What happens to fatty acids after entering epithelial cells?

  They are reformed into triglycerides
• What is a chylomicron?

  A triglyceride combined with a protein
• How are chylomicrons released from epithelial cells?

  By exocytosis
• Where do chylomicrons go after being released?

  Into the lacteal or lymph vessel
• How do lipids eventually enter the capillary system?

  Through the lacteal draining into capillaries
• What are the key processes involved in digestion and absorption?

  • Digestion: Hydrolysis of large molecules
  • Absorption: Uptake of small molecules
  • Enzymes: Amylases, lipases, proteases
  • Structures: Villi and microvilli for absorption
• What are the differences between physical and chemical digestion?

  • Physical digestion: Emulsification by bile salts
  • Chemical digestion: Hydrolysis by enzymes
  • Both are essential for lipid digestion
• What is the role of co-transport in nutrient absorption?

  • Active transport mechanism
  • Involves glucose and amino acids
  • Maintains concentration gradients for absorption
• What is the significance of the villi and microvilli in the ileum?

  • Increase surface area for absorption
  • Contain capillaries for nutrient transport
  • Facilitate rapid absorption of digested nutrients
• How do bile salts enhance lipid digestion?

  • Emulsify large lipid droplets
  • Increase surface area for lipase action
  • Facilitate faster hydrolysis of triglycerides
• What happens to fatty acids and monoglycerides after absorption?

  • Reformed into triglycerides
  • Packaged into chylomicrons
  • Released into lacteals for transport
• What is the process of exocytosis in nutrient absorption?

  • Release of chylomicrons from epithelial cells
  • Involves vesicle fusion with the cell membrane
  • Allows entry into the lymphatic system
• How do nutrients enter the bloodstream after digestion?

  • Through capillaries in the villi
  • Chylomicrons enter lymph vessels
  • Nutrients transported to the liver and body