Transport Across Cell Membranes Flashcards
What is diffusion?
Net movement of molecules down a concentration gradient (area of high concentration to low concentration) to reach an equilibrium.
How does concentration gradient affect the rate of diffusion?
The steeper the gradient (more of a difference) the faster diffusion will be
How does temperature affect the rate of diffusion?
Warmer molecules have more kinetic energy, so they move around faster.
This means that, as temperature increases the rate of diffusion increases.
How does the size of molecules affect the rate of diffusion?
Smaller molecules diffuse faster.
How does the surface area of the cell membrane affect the rate of diffusion?
Faster diffusion
How does stirring affect the rate of diffusion?
Increases the movement of molecules so diffusion is faster.
What is osmosis?
Movement of water molecules from a region of high concentration to a low concentration, across a partially permeable membrane.
What is active transport?
Molecules move against the concentration gradient; from an area of low concentration to an area of high concentration.
How do root hair cells use active transport?
Root hair cells use active transport to move mineral ions against the concentration gradient into cells.
How does the small intestine use active transport?
The cells of the small intestine moves sugar molecules against the concentration gradient into the blood.
Where does the energy for active transport come from?
Aerobic respiration
Why does active transport require energy?
For carrier proteins in the mitochondria to move.
