Question

cell membranes have many functions for the cell including transporting important macromolecules and molecules between intracellular and extracellular space. in the image the membrane is moving glucose from an area with high concentration to an area of low concentration. the membrane is using a carrier protein to allow the macromolecule due to its considerable size across the membrane. what type of cellular movement is transferring the glucose?
a. active transport
b. simple osmosis
c. simple diffusion
d facilitated diffusion

Explanation:

• Active Transport: Requires energy (ATP) and moves substances against the concentration gradient. But here glucose is moving from high to low concentration, so not active transport.
• Simple Osmosis: Refers to the movement of water molecules across a semi - permeable membrane. Glucose is not water, so this is incorrect.
• Simple Diffusion: Does not require a carrier protein. Since glucose is using a carrier protein (due to its size), simple diffusion is wrong.
• Facilitated Diffusion: Moves substances (like glucose here) from high to low concentration with the help of a carrier protein (as described in the problem).

Answer:

D. Facilitated Diffusion