Question

A cell wishes to import glucose from its environment. For each mode of transport noted below indicate if that is not transport is a potential option for the cell. If the mode of transport is not an option, indicate why this mode is not an option. If the mode of transport is an option, explain when this mode would be useful. (Each answer limited to two sentences or less. Run-on sentences not allowed.) simple diffusion facilitated diffusion active transport

Answer 1

1) Simple diffusion: Glucose molecule cannot pass through the cell membrane via simple diffusion as the size of Glucose molecule is too large.

Glucose is transported by either facilitated diffusion or active transport depending on the specific metabolic needs of the cell.

2) Facilitated diffusion: Glucose can be transported by this method.The carrier proteins bind to glucose molecule which causes a conformational change, resulting in translocation of glucose from one side of the membrane to the other.Example-glucose in RBC

3)Active transport: Active transport of glucose is driven by Na+ gradient which is responsible for the uptake of glucose from the intestinal lumen.The transport of Na+ ion in the energetically favourable direction drives the uptake of glucose against its concentration gradient.Example- epithelia of small intestine