1.3 Diffusion Flashcards
Define diffusion.
The net movement of molecules or ions
from a region where they are more highly
concentrated to one where their
concentration is lower.
Is Diffusion passive?
Yes.
What are the 3 main factors that determine the rate of diffusion?
The steepness of the concentration gradient, the surface area and the thickness of the exchange surface.
What are the other factors that affect the rate of diffusion?
Temperature, the molecule type and the nature of the plasma membrane.
Why does surface area affect the rate of diffusion?
Because the more
molecules or ions can cross the membrane at any one
moment increases the rate.
Which way do molecules move in a concentration gradient?
Down a concentration gradient.
If diffusion is a passive process, what does that mean?
Means no energy is used
to make the molecules move, they have a natural kinetic energy.
What molecules diffuse through cell membranes?
Oxygen and carbon-dioxide.
Why can oxygen diffuse through cell membranes?
It is non-polar so it diffuses quickly.
Why can carbon dioxide diffuse through cell membranes?
It is non-polar and very
small so diffuses
quickly.
