Membrane Structure and Function
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34 terms
Terms | Definitions |
|---|---|
 Fluid-mosaic model | -states that plasma membrane is a fluid phospholipid bilayer w/protein molecules that are partially or wholly embedded -proteins are irregularly scattered -hydrophilic(polar) heads and hydrophobic (nonpolar) tails |
| Phospholipid bilayer | has embedded proteins |
| plasma membrane | -selectively permeable -separates internal environment from external environment -controls transport of materials in/out of cell |
| functions of membrane (5) | -protection -communication -selectively permeable -respond to environment -recognition |
| types of plasma membrane proteins (5) | -channel -carrier -receptor -cell recognition -enzymatic |
| integral proteins | -transportation -receptors for diff. hormones |
| channel protein | allow molecules to pass through freely and transports large molecules (based on size) |
| carrier proteins | -assist ions and charged molecules -selective: only moves a specific molecule in/out of cell -bonds to molecules and changes their shape for transport -uses 2 types of transport: active and facilitated |
| cell recognition proteins | -help body defend against invaders MHC glycoproteins are diff for each person, so organ transplants are risky |
| receptor proteins | shaped so a specific molecule can bind to it -causes a cellular response |
| enzymatic proteins | -begin digestion -catalyzes a specific reaction |
| peripheral proteins | -help stabilize cytoskeleton |
| carbohydrate chain | -provides a glycocalyx coating -reception of signal molecules -cell to cell recognition |
| actin filaments | -transportation -mechanical strength |
| cholesterol | -a major lipid in animals -maintains fluidity -stiffens & strengthens -makes membrane impermeable to other molecules -secures important proteins |
| glycolipid | -has a carb chain attached to a hydrophobic tail -provide energy -markers for cellular recognition |
| glycoprotein | -has a carb chain -assists in all functions of carbohydrate chain |
| Passive transport | -doesn't require energy -goes down a concentration gradient |
| active transport | -requires energy (ATP) -moves AGAINST concentration gradient -uses carrier proteins to transport specific molecules |
| diffusion | movement of molecules from an area of high C to low C ALWAYS passive |
| osmosis | diffusion of water across a selectively permeable membrane |
| tonicity | -strength of a solution w/ respect to osmotic pressure |
| isotonic | -relative solute -concentration in 2 solutions are equal |
| hyptonic | more water and less solute outside cell than inside water moves in faster than it leaves cells swell, and possibly explode CYTOLYSIS=cell bursts (animals) |
| turgor pressure | -in plants -a good thing! supports plants! :) |
| Hypertonic | less water and more solute if water leaves, cells shrivel IN PLANTS: plasmalysis IN ANIMALS: crenation |
| ion pumps | Na+ and K+ (Salt and Potassium) |
| exocytosis | vesicle containing large molecules transported to membrane and left behind |
| endocytosis | bringing in large molecules |
| phagocytosis | cell eats |
| pinocytosis | cell drinks |
| receptor-mediated endocytosis | cell brings in a specific molecule |
| osmotic pressure | pressure developed from osmosis |
| facilitated transport | the movement of a solute from an area of higher concentation to an area of lower concentration, requires no energy, and carrier molecule, GLUCOSE uses this |
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