Diffusion
Movement of molecules from an area of higher concentration to an area of lower concentration.
Cell membrane
the cell's boundary from it's environment
Facilitated diffusion
Passive diffusion that is aided by transport proteins or channels in the cell membrane. It does not require cellular energy.
Cell membrane function
regulates what enters and leaves the cell
Cell membrane channels and pumps
made of proteins
Osmosis
Diffusion of water across a membrane
Passive Diffusion Process
No energy is needed for diffusion to take place.
Hypertonic
A solution that has more solutes (higher concentration) than another solution
Hypotonic
A solution that has fewer solutes (lower concentration) than another solution
Isotonic
A solution that has the same concentration of solutes as another solution
Active transport
The movement of materials through a cell membrane using energy. It requires ATP.
Endocytosis
The process by which large molecules are taken into the cell
Exocytosis
The process by which waste molecules are expelled or released from the cell
Simple Diffusion
Molecules move directly through the membrane without any assistance.
Facilitated diffusion
Carrier proteins help transport large molecules into a cell.
Concentration Gradient
The difference in concentration of solutes on two sides of a membrane
The rate of diffusion is __________________ when there is a larger surface area (larger cell membrane) for diffusion to take place.
higher
The rate of diffusion is __________________ when there is a greater difference between the concentration of the two regions where diffusion is taking place.
higher
The rate of diffusion is ___________________ when there are thicker barriers, as opposed to thinner barriers.
lower