SB1i Flashcards
What is diffusion?
The net movement of particles from a region of higher concentration to a region of lower concentration, which then spread out uniformly.
What is a concentration gradient?
A difference between 2 concentrations. The bigger the difference between concentrations, the steeper the concentration gradient and the faster diffusion occurs.
Check Biology page 24.
What is a partially permeable or semi-permeable membrane?
A membrane that allows some molecules through it and not others.
What is osmosis?
The diffusion of small molecules of a solvent through a semi-permeable membrane. The overall movement of solvent molecules will stop when the concentration of solutes is the same on both sides of a membrane.
How do you find the percentage change in mass?
(Final mass - initial mass)
__________________________ x100
Initial mass
What is active transport?
Transporting molecules against a concentration gradient or transporting molecules that are too big to diffuse through the cell membrane.
How is active transport carried out?
Using transport proteins in cell membrane. The transport proteins capture certain molecules and carry them across the cell membrane. This is an active process and so requires energy.
Check Biology book page 25.
Which type of processes are osmosis and diffusion?
They are passive processes, so they don’t require an input of energy.
