3.3.3 digestion and absorption Flashcards
(18 cards)
what enzyme digests carbohydrates?
amylase
how does amylase breakdown starch?
catalyses hydrolysis reactions that break glycosidic bonds to form maltose
where is amylase produced?
salivary glands
pancreas which releases it into the small intestine
what enzyme digests lipids?
lipase
how does lipase breakdown lipids?
hydrolysis of ester bonds to produce monoglycerides and fatty acids
what do bile salts do?
produced by the liver and emulsify lipids
once the lipid is hydrolysed, the bile stick to monoglycerides and fatty acids to form micelles
why is it important to emulsify lipids?
small lipid droplets have a bigger surface area so an increased surface area for lipases to work on
what are membrane bound disaccharidases?
enzymes attached to the cell membranes of epithelial cells lining the ileum
what disaccharidase hydrolysed sucrose ?
sucrase
what disaccharidase hydrolyses maltose?
maltase
what disaccharidase hydrolyses lactose?
lactase
what enzymes digest proteins?
endopeptidases
exopeptidases
what do endopeptidases do?
act to hydrolyse bonds within a protein
what do exopeptidases do?
act to hydrolyse peptide bonds at the end of the proteins, they remove single amino acids
what do dipeptidases do?
they are exopeptidases that work specifically on dipeptides
they separate two amino acids and hydrolyse a peptide bond
how are monosaccharides absorbed?
active transport with sodium ions via a co-transporter protein
how are monoglycerides and fatty acids absorbed?
micelles help to move monoglycerides and fatty acids
micelles constantly break up and reform they can release monoglycerides and fatty acids
how are amino acids absorbed?
sodium ions are actively transported out of the epithelial cells into the ileum, they diffuse back into the cells through sodium-dependent transporter proteins carrying amino acids with them
