Final answer:
Passive transport of molecules across a membrane is influenced by factors such as the concentration gradient, the size of molecules, temperature, and membrane fluidity.
Step-by-step explanation:
The factors that affect the rate of passive transport of molecules across a membrane include the concentration gradient, the size of the molecules, the temperature, and the fluidity of the membrane. Passive transport involves the movement of substances from an area of higher concentration to an area of lower concentration without the use of cellular energy. Small uncharged molecules can move across the membrane directly by simple diffusion, while other substances require facilitated diffusion involving transport proteins.
- Concentration Gradient: A greater difference in concentration between the two sides of the membrane will increase the rate of passive transport.
- Molecule Size: Smaller molecules diffuse more easily and therefore pass through the membrane faster than larger molecules.
- Temperature: As the temperature increases, the rate of passive transport typically increases due to higher molecular movement.
- Membrane Fluidity: A more fluid membrane allows for easier passage of molecules through the lipid bilayer.