B1- Diffusion Flashcards
What is diffusion?
The spreading out of particles from an area of higher concentration to an area of lower concentration.
Diffusion occurs in both solutions and gases.
In which substances does diffusion occur?
Diffusion occurs in solutions and gases.
Particles in these substances are free to move about randomly.
What is an example of diffusion in gases?
The smell of perfume diffusing through the air in a room.
Perfume particles spread out in the air.
How does the concentration gradient affect diffusion rate?
The bigger the concentration gradient, the faster the diffusion rate.
Concentration gradient refers to the difference in concentration.
What effect does temperature have on diffusion?
A higher temperature increases the diffusion rate because particles have more energy and move around faster.
What is the role of cell membranes in diffusion?
Cell membranes hold the cell together but also allow substances to move in and out.
They are selectively permeable.
What types of molecules can diffuse through cell membranes?
Only very small molecules such as:
* Oxygen
* Glucose
* Amino acids
* Water
Which molecules cannot diffuse through cell membranes?
Big molecules like starch and proteins cannot fit through the membrane.
Describe the movement of particles during diffusion through a cell membrane.
Particles move from an area of higher concentration to an area of lower concentration.
What happens to particle movement if there are more particles on one side of the membrane?
There is a net movement from the side with more particles to the side with fewer particles.
How does surface area affect the rate of diffusion?
The larger the surface area of the membrane, the faster the diffusion rate.
