digestion and absorption
- Created by: Margaret Hobart
- Created on: 12-05-21 10:14
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- digestion and absorption
- digestion
- larger molecules hydrolysed to smaller molecules
- enzyme hydrolysis
- lipases
- lipids -> monoglycerides + fatty acids
- ester bond
- made in pancreas and small intestine
- bile salts produced in the liver and emulsify lipids
- form micelles
- larger SA:VOL
- bile salts produced in the liver and emulsify lipids
- lipids -> monoglycerides + fatty acids
- proteases
- peptidases
- endopeptidases
- hydrolyse peptide bonds within a protein
- made in pancreas, excreted in small intestine
- e.g. trypsin and chymotryspin
- exopeptidase
- hydrolyse peptide bonds of terminal amino acids
- Membrane-bound dipeptidases - hydrolyse peptide bonds in dipeptides
- endopeptidases
- peptidases
- carbohydrases
- Amylase - hydrolyses glycosidic bonds in starch, produces maltose
- Maltase - hydrolyses glycosidic bonds in maltose, produces glucose
- Membrane-bound disaccharidase (maltase, sucrase, lactase)
- lipases
- absorption
- products of digestion are absorbed across the ileum into the bloodstream
- monosaccharides
- absorbed via active transport with sodium ions via co-transporter protein
- amino acids
- sodium ion concentrationgradient needed (ATP)
- absorbed via active transport with sodium ions via co-transporter protein
- amino acids
- monoglycerides and fatty acids
- micelles are constantly breaking down and reforming
- whole micelles not absorbed
- lipid-soluble
- non-polar
- diffuse directly across epithelial cell membrane
- non-polar
- micelles are constantly breaking down and reforming
- adaptations
- ileum
- folded and has villi
- increase SA
- thin
- shorter diffusion distance
- contain muscle
- can mix contents - maintaining gradient
- folded and has villi
- ileum
- digestion
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