co-transport

Question 1

how is glucose absorbed?

Answer 1

using sodium co-transport

Question 2

describe how sodium ions leave the ileum epithelial cells into the blood?

Answer 2

active transport using a carrier protein in the membrane

this process requires the hydrolysis of to provide the energy to move sodium ions against their concentration gradient.

Question 3

what does the removal of sodium ions from the epithelial cell establish?

Answer 3

a concentration gradient for the movement of sodium ions into the cell from the small intestine lumen

Question 4

how do sodium ions move into the cell from the small intestine lumen?

Answer 4

facilitated diffusion

doesn’t require energy but does require a complementary shaped carrier protein

Question 5

what is special about the carrier protein which transports sodium ions into the cell?

Answer 5

it has two receptor sites

one complementary to sodium ions and the other to glucose

Question 6

what is the rule for what is necessary for co-transport of glucose using sodium to occur?

Answer 6

both sodium ions and glucose need to bind to the carrier protein for transport to occur

Question 7

what does the co transport of glucose with sodium ions enable?

Answer 7

glucose to be transported into the epithelial cell against its concentration gradient

Question 8

what happens to the glucose once it has been moved into the epithelial cell?

Answer 8

it moves into the blood via facilitated diffusion using a carrier protein with a complementary shaped receptor site.