1.4 Membrane transport

Question 1

Outline how molecules move across a membrane by simple diffusion

Answer 1

Membranes are porous, allowing diffusion.
Diffusion is a passive moment of particles from an area of high concentration to an area of low concentration, due to random motion.
This diffusion continues to occur until concentrations are equal.

Question 2

Explain the role of protein pumps in active transport

Answer 2

They can move solutes against a concentration gradient, using energy from ATP. Protein pumps are specific for the molecules transported, and change shape when transporting the molecule.

Question 3

Explain Facilitated diffusion.

Answer 3

The movement of particles from an area of high concentration to an area of low concentration,, through channel proteins. It is a passive transport, which transports molecules that cannot pass through the phospholipid bilayer. The channel protein will be specific to the molecule it transports.

Question 4

State the name of the structures formed within the cell by endocytosis

Answer 4

vesicles