digestion

• carbohydrates

  1. mouth → chewing ↑ SA + mixes food with saliva (contains amylase)
  2. carbs (starch) breaks down into smaller disaccharides (maltose) by hydrolysing glycosidic links b/w each monosaccharide
  3. small intestine → disaccharides (maltose) broken down by enzymes (maltase) into monosaccharides

  CELLULAR RESP EQUATION
• proteins

  1. structure unravelled by HCL + muscular contractions in stomach
  2. stomach: proteins broken down by enzymes (pepsin) → polypeptide
  3. SI: polypeptide → smaller dipeptides → amino acids
• lipids (triglycerides)

  enzyme-catalysed hydrolysis in digestion

  1. pass thru digestive tract (triglyceride is insoluble in water)
  2. SI: bile used to process triglycerides (emulsifies fats + ↑ SA of fats)
  3. pancreas: enzyme (lipase) hydrolyses triglycerides → access more triglyceride molecules + increase hydrolysis rate
  4. intestine: lipase catalyses all 3 ester bonds
  5. glycerol + fatty acids passed into bloodstream to liver → reformed into triglycerides
• cellulose (aka dietary fibre)

  • hydrolysed by cellulase (most animals dont hv enzyme)
  • diet high in cellulose/fibre provides bulk to help food pass thru digestive system → too little = constipation, haemorrhoids, colon cancer
  • Cellulose hydrolysed = small molecules absorbed