Movement Across Membrane Flashcards
What does the fluid mosaic model resemble?
this model suggest that a plasma membrane consists of a double layer of lipid, and that proteins are embedded in this layer.
Hydrophilic- water loving head
Hydrophobic- water hating tail
What is the function of the plasma membrane?
Boundary of a cell, controls the internal environment of a cell by controlling the movement of substances into and out of the cell
What is diffusion?
A net movement of a substance from a higher concentration to a lower concentration.
Is energy required for diffusion?
No energy is required, happens naturally.
Facilitated diffusion
Is the diffusion through protein channels.
No cellular energy required
Protein channels allow substances to cross the membrane that cannot cross the lipid bilayer.
Ions, glucose and amino acids all rely on protein channels
Active transports
Active transport is against the concentrated gradient because IT USES ENERGY.
Where does the energy for active transport come from
ATP
Carrier proteins
Do not extend through the membrane
Bond and drag molecules through the bilipid layer and release them on the opposite side
What is osmosis?
Diffusion of water through a semi permeable membrane from a high concentration of water to a low concentration of water.
No energy is required and movement occurs down the concentration gradient.
Hypotonic
Has a higher concentration of dissolved substances than the cell or solution.
More water entering the cell, the cell will get larger and will eventually burst.
Isotonic
Has the same concentration of dissolved substances in the cell or solution
Water is going to come in and water will go out at the same time
Hypertonic
Has a lower concentration of dissolved substances in the cell or solution
- lose water faster, cell will gradually shrink in size.
Turgid
When the membrane of the plant cell is being pushed up against the wall
Opposite of turgid
Flaccid
