Digestion and absorbtion

Question 1

what is digestion?

Answer 1

the process in which large biological molecules are hydrolysed by enzymes to produce smaller molecules that can be absorbed across cell membranes and assimilated

Question 2

what does the digestive system consist of?

Answer 2

the gut/alimentary canal and associated glands

Question 3

what are the three enzymes in digestion?

Answer 3

amylase protease lipase

Question 4

where is amylase produced?

Answer 4

salivary glands and pancreas

Question 5

where is protease produced?

Answer 5

stomach and pancreas

Question 6

where is lipase produced?

Answer 6

pancreas

Question 7

what does amylase break down?

Answer 7

starch into maltose

Question 8

what does protease break down?

Answer 8

proteins into amino acids

Question 9

what does lipase break down?

Answer 9

lipids into fatty acids and glycerol

Question 10

what part of the body do these enzyme reactions occur

Answer 10

A- mouth/small intestines P-stomach/small intestines L-small ontestines

Question 11

explain the process of food and what happens in these stages?

Answer 11

stage 1-injestion - food taken in from mouth
stage 2- digestion - enzymes break large insoluble molecules into smaller soluble ones
stage 3 - absorbtion - the products of digestion are absorbed through the lining of the intestines
stage 4 - egestion - removal of faeces containing undigested food, bacteria, enzymes etc

Question 12

explain carbohydrate digestion?

Answer 12

starch is hydrolysed by amylase into maltose. then maltose is hydrolysed by maltase into glucose

Question 13

explain how is glucose absorbed?

Answer 13

via co-transport

Question 14

explain protein digestion?

Answer 14

protein hydrolysed by endopeptidase into smaller polypeptides then hydrolysed by exopeptidases into dipeptides which are broken down by dipeptidases into amino acids

Question 15

why can we not use endopeptidase to break down smaller polypeptides aswell?

Answer 15

endopeptidase only breaks the bonds within the polypeptide so will take a very long time to break fully

Question 16

exopeptidases hydrolyse..?

Answer 16

peptide bonds at the end of a protein removing single amino acids

Question 17

explain how amino acids are absorbed?

Answer 17

by co-transport

Question 18

explain the digestion of lipid?

Answer 18

lipids are hydrolysed by bile slats into emulsified lipids which are hydrolysed by lipase into fatty acids + glycerol+ monoglycerides

Question 19

explain how lipids are absorbed?

Answer 19

• lipids are broke down into emulsified droplets by bile salts Which is then hydrolyses by lipase into micelles
• micelles and come into contact with epithelial cells and break down and release the monoglycerides and fatty acids
• (high concentration of micelles outside of epithelial cells and a low concentration inside epithelial cells) diffuse into the epithelial cells
• where they form triglycerides in the (smooth) ER.
• triglycerides combine with proteins in the golgi body to form chylomicrons.
• chylomicrons move out of epithelial cells by exocytosis and enter the lacteal where they are transported.

Question 20

FINISH