inserted into phospholipid bilayer
not embedded into phospholipid bilayer, but are attached to the membrane surface
how do integrals stick to the membrane?
solubility of amino acid
where are carbohydrates found in the membrane?
only in outer surface
form glycophospholipids and glcoproteins; recognize self vs. others
3 types: 1. diffusion 2. osmosis 3. facilitated diffusion; does not require energy
net movement of atoms, ions, or molecules downa concentration gradient
when the concentration is equal on both sides; no net movement of materials
factors that efffect difusion
1. concentration 2. temp. 3. pressure 4. particle size 5. mixing
diffusion of water
cell and water are equal in concentration; no change in cell size
cells water is lower than outside water; water moves into cell; cells swells, may burst
cells water is higher than outside water; water moves out of cell; cell shrinks
regulation of solute concentrations and water balance by a cell or organism
swollen; only in plant cells
limp; lacking stiffness; on in plant cells
cytoplasm shrivels and plasma membrane pulls away from the cell wall, occurs when cell loses water in hypertonic solution; only in plant cells
uses transport protein to help materials through the cell membrane, no ATP
proteins that transport specific substances across a biological membrane; molecule specific; undergoes change in shape;
Protein channel in a cell membrane that allows passage of a specific ion down its concentration gradient.
A protein channel in a cell membrane that opens or closes in response to a particular stimulus.
3 types of active transport
1. carrier mediated 2. endocytosis 3. exocytosis
carrier mediated transport
active transport of materials into cells AGAINST the concentration gradient, high to low
sodium potassium pump
moves sodium out of cell and potassium in, 3 sodium, 2 potassium; in animal cells; creates a positive charge on outside and negative inside
movement of H+ that allows other material to be transported into the cell as the H+ diffuses back across the cell membrane
process by which a cell surrounds and engulfs substances; pinches off from the cell membrane and becomes a membrane-bound organelle; 3 types: pinocytosis, phagocytosis, receptor-mediated
membrane bound organelle
endocytosis involving the transport of solutes or fluids
endocytosis involving the transport of large particles or whole cells
movement of specific molecules into a cell by binding to specifc cites on the cell even though they may not be highly concentrated in teh extra-cellular fluid
molecules that bind
process by which vessicles inside a cell fuses with the cell membrane and release its contents to the external environment, how proteins exit cells
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