Co-transport

Question 1

What is cotransport?

Answer 1

An active method of transporting remaining glucose molecules in lumen (from digestion) into cell when the concentration gradient falls so facilitated diffusion cannot occur

Question 2

Step 1 of cotransport

Answer 2

Na+ ions are actively pumped out of cells into blood by Na+K+ATPase protein pump
This is active transport
So there is a higher concentration of Na+ outside of cell than inside

Question 3

Step 2 of cotransport

Answer 3

A Na+ ion conc gradient is established
Higher concentration outside the cell than inside

Question 4

Step 3 of cotransport

Answer 4

A cotransporter protein facilitates the diffusion of these Na+ ions down their concentration gradient and pulls in glucose molecules against their gradient at the same time (using energy from conc gradient of Na+ ions)

Question 5

Step 4 of cotransport

Answer 5

Glucose can passively diffuse out through carrier proteins of cell into blood by facilitated diffusion down its conc gradient to maintain a concentration gradient of glucose lower inside cell and higher outside

Question 6

What is the benefit of cotransport?

Answer 6

Maximum absorption of glucose from lumen into cells then into blood