4.2: Diffusion
Diffusion is the passive movement of molecules from a high to low concentration until equilibrium is reached. Factors like concentration gradient, surface area, and diffusion distance affect its rate. Facilitated diffusion involves specific protein channels and carrier proteins that help transport larger or charged molecules across the membrane without using energy.
Define diffusion
The net movement of molecules or ions from an area where they are more highly concentrated to an area where their concentration is lower until evenly distributed
Key Terms
Define diffusion
The net movement of molecules or ions from an area where they are more highly concentrated to an area where their concentration is lower until even...
State three factors that affect the rate of diffusion
-Larger concentration gradient=faster
-Larger surface area= faster because there are more points of access for diffusion to occur
-Shorter di...
Describe facilitated diffusion
Diffusion along a concentration gradient involving carrier proteins and protein channels
Passive process (doesn’t require ATP)
Occurs at spec...
How do protein channels work?
-Water filled hydrophilic channels across the membrane
-Allow specific water soluble ions to pass through
-If the particular ion is not prese...
How do carrier proteins work?
-When a specific molecule is present it binds to the protein
-This causes it to change shape in such a way that the molecule is released to the ...
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| Term | Definition |
|---|---|
Define diffusion | The net movement of molecules or ions from an area where they are more highly concentrated to an area where their concentration is lower until evenly distributed |
State three factors that affect the rate of diffusion | -Larger concentration gradient=faster |
Describe facilitated diffusion | Diffusion along a concentration gradient involving carrier proteins and protein channels |
How do protein channels work? | -Water filled hydrophilic channels across the membrane |
How do carrier proteins work? | -When a specific molecule is present it binds to the protein |