3.3.3 digestion Flashcards
what is digestion
the breakdown of large insoluble molecules into small soluble molecules which can be absorbed by epithelial cells
what is the function of amylase
catalyses the hydrolysis of starch into maltose
where is amylase produced
salivary glands
pancreas
function of maltase
hydrolyses maltose into 2 glucose monomers
function of sucrase
hydrolyses sucrose into glucose + fructose
function of lactase
hydrolyses lactose into glucose + galactose
why is maltase described as membrane-bound
maltase is not released into the ileum, it is part of the cell-surface membrane of epithelial cells
where are lipases made + where do they work
pancreas + small intestine
where are bile salts produced + stored
produced in the liver + stored in the gallbladder
what is the function of bile salts
they emulsify lipids to form droplets called micelles.
this increases the surface area of the lipid allowing faster hydrolysis of lipids by lipase
what is the role of micelles in the absorption of lipids
micelles break down when they come into contact with epithelial cells releasing monoglycerides + fatty acids
how are the products of lipids absorbed
monoglycerides + fatty acids diffuse across the cell-surface membrane into the epithelial cells as they are non-polar
what is an endopeptidase
an enzyme that hydrolyses the peptide bond in the middle of the protein
what is an exopeptidase
an enzyme that hydrolyses the peptide bond at the end of a protein, removing amino acids from a protein
what is a dipeptidase
a membrane-bound exopeptidase that works on dipeptides. it hydrolyses the peptide bond between 2 amino acids
