Term
| What do we mean when we describe the plasma membrane as a fluid mosaic? |
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Definition
it is fluid lipid component - flexible and dynamic phospholipid bilayer. separates cell from external environment
mosaic of proteins which allow cell to interact with environment - only certain substances can cross |
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Term
| What types of lipids are in plasma membrane? |
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Definition
| phospholipids with cholesteral |
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Term
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Definition
penetrate hydrophobic core of lipid bilayer
transmembrane - proteins cross entire membrane |
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Term
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Definition
| are not embedded in bilayer but loosely bound to surface |
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Term
| The bilayer is a double layer of what type of molecule? |
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Definition
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Term
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Definition
specific for the substance
some passive/some active
can be hydrophilic
carriers change shape and shunt molecules across
ex. cystic fibrosis |
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Term
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Definition
speed up chemical reactions
active site on one side of the membrane
sometimes in groups
ex. ATP synthase |
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Term
| Signal Transduction Proteins |
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Definition
receptor proteins with binding site for specific signal molecule - leads to some cellular change
ex. growth hormone receptor |
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Term
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Definition
glycoproteins that identify cells as being certain type of cell or from individual
cell to cell recognition
ex. MHC proteins |
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Term
| Intercellular Joining Proteins |
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Definition
membrane proteins of adjacent cells join together forming junctions
ex. intestinal cells |
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Term
| Proteins for Attachment to cytoskeleton & extra cellular matrix |
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Definition
bind to cytoskeletal proteins within cell and anchor them in place
or adhere to extra cell. matrix outside cell connecting them to tissues |
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Term
| What is the role of carbohydrates in cell recognition? |
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Definition
cell to cell recognition
varies by species, ind of a species, tissues in the ind, cells in the ind. |
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Term
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Definition
| cells regulation of what substances cross the plasma membrane - depends on the type and distribution of membrane lipids and proteins, the polarity, the size |
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Term
| How do active and passive membrane transports differ? |
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Definition
passive does not require energy
active requires energy input from atp |
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Term
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Definition
| when two areas exist with different concentrations of a substance |
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Term
| How does a concentration gradient “go down”? |
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Definition
| when molecules move from high concentration to low concentration |
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Term
| How does a solution go against the concentration gradient? |
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Definition
requires energy
molecules move from low con. to high con. |
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Term
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Definition
movement of molecules from area of high con. to low con. due to random molecular motion (spontaneous) - eventually reaches equilibrium where molecules are evenly distributed
passive transport |
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Term
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Definition
diffusion of water across semi permeable membrane through tiny aquaporins
passive, down the gradient |
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Term
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Definition
greater concentration of solute than the otherHy solution
when cell is in hyper. solution water will exit cell - cell will shrink |
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Term
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Definition
lower concentration of solute than the other solution
when cell in in hypo. solution water will enter cell - cell will swell |
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Term
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Definition
solutions have the same concentration of solute as another solution
when cell is in isot. solution there is no net movement of water - cell will maintain its shape |
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Term
| How do animal cells react in hypertonic and hypotonic solutions? |
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Definition
hypertonic - cells will shrivel
hypotonic- cells will burst |
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Term
| How do plant cells react in hypertonic and hypotonic solutions? |
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Definition
Hypertonic - cells will become plasmolyzed - pm and cell contents pull away from cell wall
Hypotonic - cells will become turgid |
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Term
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Definition
type of diffusion facilitated by transport proteins
ions are transported across membrane by channels or carrier proteins
does not require energy, passive, molecules go down in concentration gradient |
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Term
| How does water cross the plasma membrane? |
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Definition
| osmosis (diffusion of water) through aquaporins |
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Term
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Definition
VESICLES used to move large molecules or particles in or out of cell
active process - requires ATP to move vesicles
endocytosis - vesicles taken into cell
exocytosis - vesicles taken out of cell |
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Term
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Definition
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Term
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Definition
| vesicles taken out of cell |
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Term
| How do phagocytosis and pinocytosis differ? |
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Definition
phagocytosis - engulfing of SOLID particles
pinocytosis - engulfing of LIQUID substances |
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Term
| What is the difference between facilitated and active transport? |
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Definition
facilitated uses proteins
active uses ATP |
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Term
| How does receptor mediated Endocytosis differ from regular endocytosis? |
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Definition
allows cell to engulf LARGE quantities of SPECIFIC substances
coated pits on the plasma membrane of cell which are lined with receptors for specific substance |
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Term
| Passive Membrane Transport |
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Definition
does not require energy transport
2 areas exist with different concentrations of a substance (concentration gradient)
molecules move from high concentration to low concentration (going down on concentration gradient) due to random molecular motion
ex. diffusion |
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Term
| Active Membrane Transport |
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Definition
requires energy from ATP
carriers move molecules across membrane
molecules moved against the gradient |
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Term
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Definition
pumps Na+ outside of cell and K+ inside of cell - - produces chemical gradient
produces internal environment very different from external environment
active transport, against gradient |
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