Digestion
The hydrolysis of large, insolvable molecules into smaller molecules that can be absorbed across the cell membrane.
Where are lipids digested
Small intestine
Bile
Greenish fluid produced by the liver made up of important digestive chemicals:
Mineral salts
Bile salts
Mineral salts
Eg. Sodium hydrogen carbonate
Neutralise stomach acid to provide neutral ph for enzymes in the small intestine
Bile salts
Lipids are emulsified by bile salts into tiny droplets increasing surface area for lipase (enzyme) to act on
How are lipids digested
Lipase hydrolyses the ester bonds between monoglycerides and fatty acids
Describe the process involved in the absorption and transport of digested lipid molecules from the ileum into the lymph vessels
Micelles contain bile salts and fatty acids / monoglycerides
Make fatty acids / monoglycerides more soluble in water
Fatty acids \ monoglycerides absorbed by diffusion
Triglycerides reformed in cells
Vesicles move to cell membrane / exocytosis
Enzymes involved in the digestion of proteins and their roles
Endopeptidases - hydrolyse peptide bonds within a polypeptide
Exopeptidase’s - break bonds between specific amino acids at the end of a polypeptide
Dipeptidases - break dipeptides into amino acids
Explain how sodium ions are involved in co-transport
Sodium ion are actively transported out of the into the lumen creating a diffusion gradient
The sodium ions then move back into the cell by facilitated diffusion and the glucose molecules are carried with it
Then glucose and sodium ions pass through the cell and into the blood by facilitated diffusion
What does salivary amylase break down starch into
Maltose
What does pancreatic amylase do
Hydrolyses any remaining polysaccharides into maltose