Digestion & Absorption (6) Flashcards
What is digestion?
hydrolysis of large, insoluble molecules into smaller molecules that can be absorbed across cell membranes
What are the enzymes involved in carbohydrate digestion and where are they located?
- amylase in the mouth
- maltase, sucrase and lactase in the membrane of the small intestine
What is amylase made from?
starch which is made from smaller polysaccharides
What are maltase, sucrase and lactase made from?
maltose, sucrose and lactose
What must happen before lipid digestion?
lipids must be emulsified by bile salts produced by the liver
this breaks down large fat molecules into smaller, soluble molecules called micelles
this increases their surface area
How are lipids digested?
lipase hydrolyses the ester bond between monoglycerides and fatty acids
Where are lipids digested?
small intestine
What are the 3 types of enzymes in protein digestion?
endopeptidases
exopeptidases
dipeptidases
What is the role of endopeptidases?
break peptide bonds between specific amino acids in middle of polypeptide
What is the role of dipeptidases?
break down dipeptides into amino acids
What is the role of exopeptidases?
break peptide bonds between specific amino acids at the end of the polypeptide
What is the advantage of co-transport?
allows certain molecules to be absorbed into ileum despite negative concentration gradient
What are 2 examples of molecules that are transported via co-transport?
monosaccharides
amino acids
Why do fatty acids and monoglycerides not require co-transport?
the molecules are nonpolar
Why do nonpolar molecules not require co-transport?
can easily diffuse across membrane of the epithelial cells
