Term
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Definition
surrounds living cells
separates from surroundings
selectively permeable
composed of phospholipids and proteins
Molecules that compose it are often amphipathic |
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Term
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Definition
has both hydrophobic and hydrophilic regions
ex. Phospholipids and membrane proteins |
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Term
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Definition
Glycerol + 2 fatty acids + 1 phosphate
-can move laterally within the plasma membrane |
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Term
| Functions of Membrane Proteins |
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Definition
-transport
-enzymatic activity
-signal transduction
-intercellular joining
-cell-cell recognition
-attachment to the cytoskeleton and the extracellular matrix (ECM) |
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Term
| Unsaturated Fatty Acids effect on Melting Point and Fluidity |
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Definition
have lower melting point/ more fluid at lower temperatures
do not pack tightly |
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Term
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Definition
| higher concentration of solutes |
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Term
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Definition
| lower concentration of solutes |
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Term
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Definition
| solute concentrations are equal |
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Term
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Definition
diffusion across membrane without spending energy
ex. During respiration, O2 diffuses across the cellular membrane |
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Term
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Definition
The movement of a solute across a biological membrane such that the movement is directed upward in a concentration gradient (against the gradient)
Requires expenditure of energy
energy supplied by hydrolysis of ATP |
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Term
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Definition
| movement of water or another solvent across a semipermeable membrane from a region of low solute concentration to one of higher solute concentration |
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Term
| Facilitated Diffusion (mediated transport) |
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Definition
movement of a solute across a biological membrane that requires the participation of one or more transport agents (ie. protein)
Can be passive, along concentration gradient
Can be active, against a concentration gradient |
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Term
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Definition
| simultaneous transport of two different substances across a biological membrane |
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Term
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Definition
| the cell secretes (exports) macromolecules by fusion of vesicles with the plasma membrane |
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Term
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Definition
the cell IMPORTS macromolecules by forming new vesicles from the plasma membrane
reverse of exocytosis |
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Term
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Definition
Type of endocytosis
A vacuole is formed with a lysosome for digestion |
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Term
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Definition
Type of endocytosis
Soluble materials (NON-SPECIFIC) are taken up into vesicles for digestion |
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Term
| Receptor-mediated endocytosis |
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Definition
Type of endocytosis
Receptor-mediated endocytosis is SPECIFIC.
Process by which specific substances are brought into the cell that are in low concentration or to be used in specific cell types. |
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Term
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Definition
| Phospholipids are arranged in the bilayer of the membrane like this: hydrophobic fatty acid chains directed inward on either side and hydrophilic phosphate groups directed outward on either side. |
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