Ch6 Digestion

Question 1

Oesophagus

Answer 1

carries food from mouth to stomach

Question 2

Stomach functions

Answer 2

1. muscular sac
2. glands produces proteases
3. acidic pH denatures amylase
4. stores and digests food

Question 3

Ileum

Answer 3

1. inner walls folded into microvilli for large SA
2. epithelial lining have membrane-bound disaccharides
3. absorbs products of digestion into bloodstream

Question 4

Large intestine

Answer 4

1. absorbs water from secretions of digestive glands

Question 5

Salivary glands

Answer 5

1. produces amylase
2. secrete by duct into mouth

Question 6

Pancrease

Answer 6

1. produces proteases
2. produces lipase
3. produces amylase

Question 7

Amylase

Answer 7

1. salivary amylase in mouth
2. pancreatic amylase in small intestine
3. hydrolyses alternate glycosidic bonds of starch
4. produces maltose

Question 8

Maltase

Answer 8

1. membrane- bound disaccharide
2. hydrolyses maltose into alpha glucose

Question 9

Sucrase

Answer 9

1. hydrolyses single glycosidic bond in sucrose
2. produces glucose+fructose

Question 10

Lactase

Answer 10

1. hydrolyses glycosidic bonds in lactose
2. produces glucose + galactose

Question 11

Bile salts

Answer 11

1. produced by liver
2. emulsifies lipids into micelles
3. increases SA
4. miscelles are water soluble vesicles that can diffuse into epithelial cells

Question 12

Lipase

Answer 12

1. hydrolyse ester bond in triglycerides
2. forms fatty acids and monoglycerides

Question 13

Endopeptidases

Answer 13

1. hydrolyse peptide bond between amino acids in centre of protein
2. produces series of peptide molecules

Question 14

Exopeptidases

Answer 14

1. hydrolyse peptide bond on terminal amino acids
2. produce dipeptides and amino acids

Question 15

Dipeptidases

Answer 15

1. hydrolyse amino acids on dipeptide
2. produce amino acids
3. membrane bound
4. csm of epithelial cells

Question 16

Absorption of glucose and amino acids

Answer 16

1. Na+ actively transported from epithelial cells into the blood by Na-K pump
2. lowers the Na+ concentration in the cell
3. Na+ move from the lumen of the small intestine into the cell down concentration gradient
4. cotransport occurs, carrying glucose or amino acids
5. glucose/amino acids moves down concentration gradient into the blood by facilitated diffusion

Question 17

Villi adaptations

Answer 17

1. increase SA for diffusion
2. thin- short diffusion pathway
3. well supplied by blood vessels- maintain diffusion gradient

Question 18

Absorption of triglycerides

Answer 18

1. monoglycerides and fatty acids diffuse across csm into epithelial cells
2. transported to ER
3. reform triglycerides
4. associate with cholesterol and lipoproteins in golgi body
5. form chylomicrons
6. secreted out by exocytosis into lacteal