Digestion Flashcards
(34 cards)
What does amylase do?
Catalyses the conversion of starch into maltose
Involves the hydrolysis of the glycosidic bonds in starch
Where is amylase produced?
Salivary glands
Or the pancreas
What enzymes are attached to the cell membranes of epithelial cells lining the ileum?
Membrane- bound disaccharides
Help to breakdown disaccharides e.g. sucrose, maltose, lactose into glucose, fructose and galactose
Involves hydrolysis of glycosidic bonds
What does lipase do?
Catalyses the breakdown of lipids into monglycerides and fatty acids
Hydrolyses the ester bonds in triglycerides to form the monoglycerides and fatty acids
Where are lipases made?
Pancreas
Where are bile salts produced?
In the liver
What do bile salts do?
Emulsify lipids
Cause the lipids to form smaller droplets (micelles)
Why are small droplets better?
Several small droplets have a bigger surface area than a single large droplet - increases the surface area of lipid that’s available for lipase to work on
What happens once the lipid is broken down?
The monoglycerides and fatty acids stick with the bile salts to form micelles
What are proteins broken down into?
Peptidases
What do proteases do?
Catalyse the conversion of proteins into amino acids by hydrolysing the peptide bonds between amino acids
What do endopeptidases hydrolyse?
Peptide bonds between amino acids in the middle of a polymer chain
2 examples of endopeptidases?
Trypsin and chemo trypsin- synthesised in the pancreas and secreted into the small intestine
Where is pepsin released?
In the stomach by cells in the stomach lining
What conditions does pepsin work in?
Acidic conditions- provided by HCL in the stomach
What do exopeptidases do>
Hydrolsyes peptide bonds between amino acids at the end of a polymer chain
What do membrane bound dipeptides do?
Hydrolyse peptide bonds between 2 amino acids
Where does protein digestion start?
In the stomach then continues in the duodenum and is fully digested in the ileum
How are lipids digested?
by lipase and the action of bile salts
What is the physical digestion for lipid digestion?
Emulsification and micelle formation
Lipids are coated in bile salts to create an emulsion
Many small droplets of lipids provides a larger SA for faster hydrolysis by lipase
What is the chemical part of lipid digestion?
Lipase hydrolyses lipids into glycerol and fatty acids
What are micelles?
Water soluble vesicles formed of the fatty acids, glycerol, monoglycerides and bile salts
What do micelles deliver to the epithelial cells of the ileum for absorption?
Fatty acids, glycerol and monoglycerides
Where are the products of digestion absorbed?
Across the cells lining the ileum
