6 - Exchange (Digestion) Flashcards
what is the biggest keyword for this topic?
HYDROLYSE/ HYDROLYSIS
what is physical breakdown
breaking food down into smaller pieces using mechanical structures (eg. teeth, stomach walls)
how is food physically broken down in stomach?
food is churned by muscle in stomach wall
benefit of physical breakdown
- provide large SA for chemical digestion
what is chemical digestion?
HYDROLYSES large, insoluble molecules into smaller soluble ones
what is hydrolysis?
process of splitting up molecules by adding water to chemical bonds that hold them together
three main types of digestive enzymes
- carbohydrases
- lipase
- proteases
where is amylase produced?
- salivary glands
- pancreas
function of amylase
- hydrolyses alternate glycosidic bonds of starch molecule
- produce the disaccharide maltose
what is maltase?
- membrane bound disaccharidase
- produced in lining of ileum
function of maltase
- hydrolyse maltose into monosaccharide a-glucose
common disaccharides in the diet
- maltose (eg. starch)
- sucrose (eg. fruits)
- lactose (eg. milk products)
function of sucrase
- hydrolyses single glycosidic bond in sucrose molecule
- produces gluc + fruc
function of lactase
- hydrolyses single glycosidic bond in lactose molecule
- produces gluc + galac
endopeptidase function
- hydrolyse internal peptide bonds between amino acids
exopeptidase function
- hydrolyse peptide bonds between terminal amino acids of peptide molecules
- … peptide molecules FORMED BY endopeptidases
why combined actions of endopeptidases and exopeptidases more efficient than exopeptidases on their own?
- endopeptidases hydrolyse internal peptide bonds and exopeptidases remove amino acids/hydrolyse peptide bonds at end
- more ends or increase in surface area for exopeptidases
dipeptidase function
- hydrolyse peptide bond between two amino acids of a dipeptide
- membrane bound
what membrane are membrane bound enzymes bound to?
- cell surface membrane of epithelial cells
- lining the ileum
adaptations of ileum
- folded villi surface
- thin walled
- contain muscles
- well supplied with blood vessels
- villi -> microvilli
function of ileum
absorbing products of digestion
DESCRIBE process of absorption of products of starch digestion
- glucose moves in with sodium into epithelial cell through symport
- sodium removed (from epithelial cell) by active transport through sodium- potassium pump into blood
- maintaining low concentration of sodium in epi. cell so steep conc. grad. between lumen and epi. cell.
- glucose moves into blood by facilitated diffusion
lipase function
- hydrolyses ester bond in triglyceride
- forms monoglycerides (ie. glycerol) and fatty acids
advantage of lipid droplets
- increase surface areas for lipase
- faster hydrolysis of triglyceride
