Digestion

Question 1

Starch digestion

Answer 1

Breaks down in parts using enzymes
Salivary glands - makes salivary amylase
Mouth - amylase hydrolyses starch to maltose. The food is chewed.
Pancreas - makes pancreatic amylase (amylase from salivary glands denatured by stomach acid)
Small intestine - pancreatic amylase further hydrolyses starch to maltose. Epithelial lining of small intestine also makes maltase. This hydrolyses maltose to alpha glucose (as well as lactase and sucrose)
Glucose absorbed by villi on small intestine

Question 2

Active transport in glucose absorption

Answer 2

Helps all glucose be absorbed
Co-transport (uses 2 molecules)
Sodium ions actively transported to blood from epithelial cells by sodium-potassium pump
Forms a diffusion gradient for sodium to enter epithelial cells from lumen - these couple with glucose
Glucose enters by facilitated diffusion with sodium ions

Question 3

Digestion of proteins

Answer 3

1) Hydrolysis of peptide bonds
2) Endopeptidases hydrolyses internal peptide bonds, turning polypeptides into smaller peptide chains (so there are more ends for exopeptidases)
3) Exopepeptidases remove terminal amino acids
4) Dipeptidases hydrolyse dipeptides into amino acids