Co-Transport:

Question 1

What is the illiuem?

Answer 1

= part of small intestine
= absorb the molecules produced in digestion
= lined by epithelial cells

Question 2

How is the general movement of how glucose transported?

Answer 2

= absorbed from the lumen of the illiuem into the epithelial cells
= move from the epithelial cells to the bloodstream

Question 3

How does this take place?

Answer 3

= after digestion there is a high concentration of glucose in the lumen of the illiuem
= move down the concentration gradient through facilitated diffusion INTO epithelical cells (carrier proteins)
= move into the blood stream + carried away

Question 4

What does the rate of facilitated diffusion depend on?

Answer 4

= size of the concentration gradient for glucose
= as glucose moves into the epithelial cells the concentration gradient falls
= cannot absorb all the avaliable glucose

Question 5

How else is glucose absorbed therefore?

Answer 5

= Active transport

Question 6

What is the first stage of this active transport?

Answer 6

= carrier protein- SODIUM POTTASIUM PUMP
= using atp actively transports sodium ions out of the epithelial cells and into the blood stream

= VERY LOW concentration of sodium
= lumen of the illiuem has a high concentration of sodium ions
= CONCENTRATION GRADIENT

Question 7

What is the sodium glucose co transporter?

Answer 7

= membrane of the epithelial cell
= sodium ions can diffuse through down the concentration gradient
= also transports glucose into the cell- agaisnt the concentration gradient- energy comes from the concentration gradient of the sodium ions

Question 8

What does epithelial cells contain?

Answer 8

= large number of mitochondria
= provide the ATP needed for the sodium pottasium pump
= membrane is folded into microvili- increases SA for membrane protein needed for facilitated diffusion and active transport