term1 Definition1term2 Definition2term3 Definition3
Please sign in to your Google account to access your documents:
Selective (differential) permeability
Plasma membrane is selective about what passes through it. Allows nutrients to enter cell but keeps out undesirable substances. Valuable cell proteins and other substances are kept within the cell, and excreta or wastes pass to the exterior.
Passive Processes
Concentration or pressure differences drive the movement
Active Processes
Cell provides energy (ATP) to power the transport process
Two types of Passive Processes
DiffusionFiltration
Diffusion
Important transport process for every cell in the body
Filtration
Usually occurs only across capillary walls
When a concentration gradient (difference in concentration) exists, the movement of molecules from a region of their higher concentration to a region of their lower concentration
Simple diffusion
Unassisted diffusion of solutes (dissolved substances) through a selectively permeable membrane
Facilitated diffusion
Substances moving by a passive transport process from high to low concentration
Example: Glucose are transported across the plasma membrane with the assistance of a protein carrier molecule
Osmosis
Flow of water across a selectively permeable membrane down its concentration gradient
Need help typing ? See our FAQ (opens in new window)
Please sign in to create this set. We'll bring you back here when you are done.
Discard Changes Sign in
Please sign in to add to folders.
Sign in
Don't have an account? Sign Up »
You have created 2 folders. Please upgrade to Cram Premium to create hundreds of folders!