Digestion & Absorption

Question 1

Describe the process of starch digestion.

Answer 1

• Starch to maltose
• Salivary/pancreatic amylase
• Maltose to glucose
• Using maltase
• Hydrolysis of glycosidic bonds

Question 2

Describe the processes involved in the absorption and transport of digested lipid molecules from the ileum into lymph vessels.

Answer 2

1. Micelles contain bile salts and fatty acids/monoglycerides
2. Make fatty acids/monoglycerides more soluble (in water) OR bring fatty acids/monoglycerides to cell/lining (of the iluem) OR maintain higher concentration of fatty acids/monoglycerides to cell/lining (of the ileum)
3. Fatty acids/monoglycerides absorbed by diffusion
4. Triglycerides reformed (in cells)
5. Vesicles move to cell membrane

Question 3

Describe the role of micelles in the absorption of fats into the cells of the ileum.

Answer 3

1. Micelles include bile salts and fatty acids
2. Make the fatty acids more soluble in water
3. Bring fatty acids to cell/lining (of the ileum)
4. Maintain higher concentration of fatty acids to cell/lining (of the ileum)
5. Fatty acids (absorbed) by diffusion

Question 4

Describe the role of enzymes in the digestion of proteins in a mammal.

Answer 4

1. Hydrolysis of peptide bonds
2. Endopeptidase act in the middle of polypeptide OR endopeptidase produces shorter polypeptides
3. Exopeptidases act at end of polypeptide OR Exopeptidase produces dipeptides/amino acids
4. Dipeptidase acts on dipeptide/between two amino acids OR dipeptidase produces single amino acids

Question 5

Describe the absorption of glucose (co-transport).

Answer 5

1. Sodium ions actively transported from ileum cell to blood
2. Maintains diffusion gradient for sodium to enter cells from gut (and with it, glucose)
3. Glucose enters by facilitated diffusion with sodium ions