Diffusion Flashcards
What is diffusion?
Diffusion is the net movement of particles from an area of higher concentration to an area of lower concentration, down a concentration gradient, as a result of their random movement.
Does diffusion require energy?
No, diffusion is a passive process and does not require energy.
What factors affect the rate of diffusion?
The rate of diffusion is affected by the concentration gradient, temperature, surface area, and the distance particles have to travel.
What is meant by a ‘concentration gradient’?
A concentration gradient is the difference in the concentration of a substance between two areas.
How does temperature affect diffusion?
Higher temperatures increase the kinetic energy of particles, causing them to move faster and diffuse more quickly.
How is diffusion important in the human body?
Diffusion is important for gas exchange in the lungs (oxygen diffuses into the blood, and carbon dioxide diffuses out) and for the movement of substances like glucose and oxygen into cells.
How does the surface area of a membrane affect diffusion?
A larger surface area increases the rate of diffusion, as there is more space for particles to pass through.
Give an example of diffusion in plants.
In plants, carbon dioxide diffuses into leaves through the stomata for photosynthesis.
What is facilitated diffusion?
Facilitated diffusion is the movement of molecules across a cell membrane through protein channels or carriers, down their concentration gradient, without energy input.
How does the thickness of a membrane affect diffusion?
A thinner membrane allows particles to diffuse more quickly because the distance they need to travel is shorter.
