Digestion and absorption Flashcards
What does amalyse catalyse?
the conversion of starch, a polysaccharide, into smaller sugar moltose, a dissacharide,. this involves hydrolysis
Where is amalyse produces?
in the salivary gland and also the pancrease, which releases amalyse into the small intestine
What are membrane bound disaccharides?
enzymes that attach to the cell membranes of the epithelial cells linning in the illeum they help to break the diassachrides into monsaccharides.
What does the enzyme lipase catalyse?
lipase catalyses the breakdown of lipids into mongycerides and fatty acids, involves the hydrolysis of ester bonds
Where is lipase made?
pancrease and they work in the small intestine
Where are bile salts produced and what do they do?
they are produced in the liver and emulsify lipids- they cause lipids to form small droplets
Why are lipids converted to small droplets?
serval lipds droplets that a bigger surface area than a single large droplet, so a increase surface area for lipase to work on
What happens when the monogylecides have been broken down?
they stick with the bile salts to form tiny structures called micelles
What are endopeptidases?
act to hydrolyse peptide bonds within a protien
What are exopeptidase?
act to hydrolyse peptide bonds at the ends of protein molecules
What are dipeptides?
they act to seperate the two amino acids that make up a dipeptide by hydrolysing the peptide bond between them
How are monosaccarides absorbed across the ileum epithelium?
glucose is aborbed by active transport with sodium ions via a co transport protien. galactose is absorbed in the same way using a co tranporter protien. fructose is abosorbed via facillitated diffustion through a diffrent transporter protein
How are monoglycerides and and fatty acids abosorbed across the iluem epithelium?
micelles help to move monoglycerides and FA towards the epithelium. the micelles break up to release the MG and FA can diffuse directly into the epithelial cell membrane because they are lipid soluble
How are amino acids absorbed across the illeum epithelium?
sodium ions are actively transported out of the iluem epithelial cells into the blood. this creates a sodium concetration gradient so they can then diffuse from the lumen of the illeum into the epithelial cells through a sodium dependent transporter proteins carrying the amiino acids with them
