Digestion And Absorbtion

Question 1

Describe to process of starch digestion 6m

Answer 1

Salivary amylase
To Maltose
Maltose
Maltose to glucose
Hydrolysis
Of glycosidic bonds

Question 2

Describe the role of micelles in the absorption of fats into the cells of the ileum 6m

Answer 2

Micelles contain bile salts and fatty acids
Make the fatty acids more soluble in water
They bring fatty acids to cell
Maintain higher concentration of fatty acids to cell
Fatty acids enter by diffusion

Question 3

Describe the processes involved in the absorption and transport of a digested lipid molecule from the ileum into lymph vessels 5m

Answer 3

Micelles contain bile salts and fatty acids
Bring fatty acids to ileum cell
Fatty acid absorbed by diffusion
Triglycerides reformed in cell
Vesicles move to cell membrane

Question 4

Describe the role of enzymes int he digestion of proteins in a mammal 4m

Answer 4

Hydrolysis of peptide bonds
Endopeptidase act in the middle of polypeptide chain
Exopeptidase produce dipeptides
Dipeptidase acts on dipeptides to produce single amino acids

Question 5

Describe the transport of glucose (Co transport) 3m

Answer 5

Sodium ions actively transported from the ileum cell to blood
Forms a diffusion gradient for sodium to enter cells from gut with glucose
Glucose enters by facilitated diffusion with sodium ions

Question 6

What is digestion

Answer 6

Process at which larger molecules are hydrolysed by enzymes to form small molecules which are absorbed into blood then assimilated into biological molecules

Question 7

Absorption of glucose 7m

Answer 7

Sodium ions actively transported out the cell through sodium potassium pump into blood
Creates concentration gradient of sodium ion
Co transport protein has two active sites complementary to sodium ion and glucose, movement only occurs when both bind
Sodium ion and glucose enter cell by facilitated diffusion using cotransporter proteins
sodium ions to enter cell down concentration gradient
glucose to enter cell against concentration gradient using co transport protein
Glucose then moves into blood by facilitated diffusion

Question 8

The rate of glucose e absorption will be affe cited by a lack of oxygen. Describe how 4m

Answer 8

Less oxygen less atp produced by mitochondria
ATP required in the active transport of sodium using sodium potassium pump
Reduced concentration gradient
Rate of transport of sodium and glucose decrease

Question 9

Explain the advantages of micelles and lipid droplet formation 3m

Answer 9

Droplet increase surface area
So faster hydrolysis
Micelles contain fatty acids and gycerol