Diffusion Flashcards
give the definition of diffusion
Diffusion is the net movement of particles (molecules or ions) from an area of higher concentration to an area of lower concentration.
will molecules diffuse both ways ?
Molecules will diffuse both ways, but the net movement will be to the area of lower concentration.
explain the concentration gradient
The concentration gradient is the path from an area of higher concentration to an area of lower concentration. Particles diffuse down a concentration gradient.
how long does diffusion continue ?
This continues until particles are evenly distributed throughout the liquid or gas.
What type of process is diffusion ?
passive as no energy is needed for it to happen
what type of molecules is simple diffusion for ?
small ,uncharged particles
what is simple diffusion ?
Movement of particles from high to low concentration without a protein .WHen particles move directly across a membrane
give an example of simple diffusion ?
Example:Oxygen and carbon dioxide can diffuse easily through cell membranes because they’re small, so they can pass through spaces between the phospholipids. They’re also non-polar, which makes them soluble in lipids, so they can dissolve in the hydrophobic bilayer.
what happens with larger molecules when dfffusing across cell membranes ?
they go extremely slowly
what happens with charged particle when diffusing ?
Charged particles, e.g. ions and polar molecules, would also diffuse slowly because they’re water soluble, and the centre of the bilayer is hydrophobic .particles diffuse through carrier proteins or channel proteins in the cell membrane instead .This is facilitated diffusion
what are carrier and channel proteins called ?
transport proteins
what do carrier proteins do ?
Carrier proteins move large molecules across the membrane, down their concentration gradient.
do all carrier proteins do all molecules ?
Different carrier proteins facilitate the diffusion of different molecules.
how do carrier proteins work ?
First, a large molecule attaches to a carrier protein in the membrane. Then, the protein changes shape. This releases the molecule on the opposite side of the membrane .
what do channel proteins do ?
transport charged particles across the membrane