4.5 Co-transport and absorption of glucose in the ileum Flashcards
(6 cards)
1
Q
What is co-transport?
A
The transport of one substance coupled with the transport of another substance across a plasma membrane in the same direction through the same protein carrier.
2
Q
How may cells be adapted for rapid transport across their internal or external membranes?
A
- increase the surface area
- increase the number of protein channels and carrier protein
3
Q
What are the examples of adaptations of epithelial cells to increase the rate of transport across their internal and external membranes?
A
- the epithelial cells that are lining the ileum (small intestine) have microvilli
↳ they provide more surface area for the insertion of carrier proteins through, which diffusion, facilitated diffusion and active transport can take place - maintaining concentration gradient of glucose between the inside of ileum and the blood
↳ glucose is continuously absorbed from the lumen of the small intestine into the bloodstream and then removed by cells during respiration - co-transport
↳ glucose or amino acids are drawn into cells along with sodium ions that have been actively transported out by the sodium-potassium pump
4
Q
How does co-transport of glucose molecules work?
A
- sodium ions are actively transported out the epithelial cell
- this maintains a much higher concentration of sodium ions in the lumen of the intestine
- sodium ions diffuse into the epithelial cells down this concentration gradient through a different type of protein carrier
- as sodium ions diffuse in, they carry either amino acids or glucose into the cell with them
- glucose/amino acids pass into the blood plasma through facilitated diffusion
5
Q
Do sodium ions move down or against the concentration gradient when moving into the cell during co-transport?
A
Down
6
Q
Do glucose molecules move down or against the concentration gradient when moving into the cell during co-transport?
A
Against
