digestion and absorption pmt flashcards

Question 1

define digestion

Answer 1

the hydrolysis of large , insoluble molecules into smaller molecules that can be absorbed across cell membranes

Question 2

which enzymes are involved in carbohydrate digestion and wheee are they found

Answer 2

amylase in mouth
-maltase , sucrase , lactase in membrane of small intestine

Question 3

what are the substrates and products of the carbohydrate digestive enzymes

Answer 3

amylase=starch into smaller polysaccharides
-maltase=maltose into 2x glucose
-sucrase = sucrose into glucose and fructose
-lactase=lactose into glucose and galactose

Question 4

where are lipids digested

Answer 4

small intestine

Question 5

what needs to happen before lipids can be digested

Answer 5

they must be emulsified by bile salts produced by the liver.This breaks down large fat molecules into smaller , soluble molecules called micelles , increasing SA

Question 6

how are lipids digested

Answer 6

lipase hydrolyses the ester bond between the monoglycerides and fatty acids

Question 7

which enzymes are involved in protein digestion and what is their role

Answer 7

endopeptidases=break between specific amino acids in the middle of a polypeptide
-exopeptidases=break between specific amino acids at the end of a polypeptide
-dipeptidases=break dipeptides into amino acids

Question 8

how are certain molecules absorbed into the ileum despite a negative concentration gradient

Answer 8

through co transport

Question 9

which molecules require co transport

Answer 9

amino acids and monosaccharides

Question 10

explain how sodium ions are involved in co transported

Answer 10

sodium ions (NA+) are actively transported out of cells into the lumen, creating a diffusion gradient.Nutrients are then taken up into the cells along the NA+ ions.

Question 11

why do fatty acids and monoglycerides not require cotransport

Answer 11

the molecules are non polar meaning they can easily diffuse across the membrane of the epithelial cells