Diffusion Flashcards
What is a passive process?
These don’t require energy from ATP and rely on the molecules kinetic energy for movement
What is diffusion?
The net movement of particles going from a high concentration to a low concentration going down the concentration gradient.
What is net movement?
The overall movement of the particles
What does equilibrium mean?
Particles are evenly dispersed, there is no concentration gradient
What is simple diffusion?
When molecules which can freely cross the phospholipid bilayer such as non-polar simple molecules which diffuses from one side to the other
What particles use simple diffusion?
Small, non-polar molecules and steroid hormones. Small polar molecules like water and urea diffuse across slower.
How does temperature affect the rate of diffusion?
If the temperature they will move faster across the membrane because the particles will gain kinetic energy and will move more
How does surface area affect the rate of diffusion?
If the surface area is larger then there will be more places for the particles to diffuse through, increasing the diffusion rate
How does diffusion distance affect the rate of diffusion?
If the wall/barrier is thicker the diffusion rate will decrease because the particles need to go over a larger distance to the other side, taking longer and slowing the diffusion rate
How does concentration gradient affect the rate of diffusion?
An increase in conc gradient increases rate of diffusion
How does the size of the molecule affect the rate of diffusion?
The bigger the molecule the slower the diffusion rate because its harder to go through the membrane
What particles use facilitated diffusion?
Large and/or hydrophilic particles like glucose and animo acids and ions that need to get through to the cell
How do small polar molecules use facilitated diffusion?
They use channel proteins, which are proteins filled with water in the membrane
How do large polar molecules use facilitated diffusion?
They use carrier proteins by binding to a transmembrane carrier protein, which then opens and allow the glucose to pass through carrier proteins are specific for a certain molecule type
What uses for transporting substances through the membrane?
Intake oxygen for respiration
Releasing excess CO2 from respiration
Releasing of toxic waste
Uptake of amino acids for proteins
Uptake of lipids for membrane
