Absorption

Question 1

How is glucose/ amino acids absorbed?

Answer 1

1. Glucose moves in with sodium into the intestinal epithelial cell
2. Via Carrier proteins (co transport protein)
3. Sodium is removed from the epithelial cell by active transport via sodium-potassium carrier protein
4. Into the blood
5. Maintaining low concentration by sodium in epithelial cell
6. Glucose moves into blood
7. By facilitated diffusion

Question 2

What is the role of Golgi in liquid absorption?

Answer 2

Golgi apparatus modifies/ processes triglycerides
Combines triglycerides with proteins
Packages for release/ exocytosis (or forms vesicles)

Question 3

Why do bile salts do?

Answer 3

They emulsify the lipid into tinier lipid droplets to increase surface area for a faster absorption

Question 4

When is facilitated diffusion used?

Answer 4

Channel proteins

Question 5

When is active transport used?

Answer 5

Carrier proteins

Question 6

What is absorbed into the ileum ?

Answer 6

Small, soluble molecules

Question 7

What is duodenum?

Answer 7

The beginning of the ileum

Question 8

How is the ileum adapted to its function.

Answer 8

Walls are folder into villi = increases the SA for faster absorption
Epithelial cells have microvilli= increases SA for faster absorption
Walls are one cell thick = shorter diffusion pathway
Many capillaries= rich bloody supply maintaining the diffusion gradient
Muscle in villi = maintains diffusion gradient by moving contents of the lumen

Question 9

Co transport of glucose/ amino acids and sodium

Answer 9

Sodium ions are actively transported out of the epithelial cell via the sodium potassium pump into the blood. This creates a lower concentration of sodium ions in the epithelial cell.Sodium ions diffuse into the epithelial cell down the concentration gradient via facilitated diffusion. As the sodium ions diffuse they carry either an amino acid or a glucose molecule with them (co transport) the glucose or amino acid molecule will pass into the blood via facilitated diffusion through a separate carrier protein. The sodium ions are moving down the concentration gradient whereas the glucose are moving against their concentration gradient

Question 10

Absorption of lipids

Answer 10

Lipid droplets contain bile salts which emulsify them into Micelles (increased SA for faster absorption). Monoglycerides and fatty acids are released.
1) fatty acids and glycerol are non polar
2) enter the epithelial cell via simple diffusion
3) travel to the smooth ER
4)to be resynthesised into a triglyceride
5) then travels to Golgi and is made into a chylomicron
6) chylomicron is released via exocytosis
7) chylomicron pass to lymphatic vessel and then into blood stream