digestion and absorbtion Flashcards
(15 cards)
define digestion (2)
● enzymes hydrolyse large insoluble molecules into small soluble molecules
● so they can be absorbed and assimilated
what does assimilated mean?
to be used by the body for a function
what enzymes are involved in starch digestion? where are they found?
● amylase (in salivary glands / mouth)
● maltase (embedded in epithelial cell membrane)
how is starch digested into glucose? (6)
● starch is hydrolysed into maltose by amylase in salivary glands, breaking glycosidic bond between starch
● amylase gets denatured in the stomach
● pancreas secretes more amylase
● by small intestine, only maltose
● maltase hydrolyses maltose into glucose, embedded in epithelial cell membrane
● glucose is absorbed and assimilated
what is the protein that allows co-transport?
● symport
● binds to two molecules at the same time
what is co-transport?
where the conc of one molecule is used to move the other molecule against its own concentration gradient
do co-transport require energy?/
no (passive)
describe the process of carbohydrate absorption
● sodium ions are actively transported out Na+ / K+ pump, which creates a concentration gradient
● glucose moves into epithelial cell by co-transport with sodium - against conc gradient
● glucose moves into the blood by facilitated diffusion
what is the process of amino acid absorption the same as? (2)
● exactly the same as carbohydrate / glucose absorption
● replace glucose with amino acid
what is protease also known as?
peptidase
what are the main types of protease? (3)
● endopeptidase
● exopeptidase
● dipeptidase
what does endopeptidase do? where is it released? (3)
● hydrolyses internal peptide bond
● increases SA for exopeptidase
● released in stomach
what does exopeptidase do? where is it released? (2)
● hydrolyses peptide bonds at the end of the polypeptide (terminal peptide bonds)
● released by pancreas
what does dipeptidase do? where is it found? (2)
● hydrolyse peptide bonds between animo acids of dipeptides to form amino acids
● found in cell membrane of epithelial cell in small intestine
