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37 Cards in this Set

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JD Robinson Unit Membrane hypothesis
cell membranes like a sandwich,
esp phospholipid (fatty acid), heads, hydrophobic tails

wrong b/c proteins inside too, need to let water soluble things inside
fluid-mosaic model
- proteins disperesed, embedded in membrane/not
->components can be arrnaged in diff ways
-> fluid components can move, lipids move around

carbs on exterior of cell, attached to proteins and lipids
peripheral proteins
not embedded in membrane
integral proteins
embedded in membrane
protein attached to carb
lipid attached to a carb
unsaturated fatty acid -> ?
increases fluidity of membrance b/c bending of hydroC chains
cholesterol -> ?
added to membrane (causes fatty acid change) can increase fluidity like unsat fat acid
unsat - high perm

sat - low perm
movement of phospholipids
move laterally (horiz) usually don't flip flop (transverse)
can't get across membranes/phopholipid layer! how get across?

facilitated diffusion
:how glucose moves in cells b/c can't get across membrane/phopho layer

:large [] to small []

:needs a way to move it, dependent on a free E gradient
:specific carrier: protein,
active transport
:carrying ions against free E gradient

:going from <er to LARGER []

:req's expend of E
uses ATP to carry one side membrane to other--> transport proteins
transport proteins
uniport- moves one solute in 1 direction, either in/out

simport - moves 2 diff mols same dir, either in/out

antiport - 2 diff mols 2 diff dirs
active transport mechanism: sodium potassium pump
found in all animal cells

integral membrane glycoprotein

inside nerve cell

energy used to move a solute against its concentration gradient

[Na] higher outside cell than [K], for each mol of ATP used, 2 K pumped into cell and 3 Na pumped out

1) 3 Na and 1 ATP molecule bind to protein pump
2) ADP released, ->ing change in pump's shsape
3) 3 Na released as 2 K bind to pump
4) Pi is released, 0>ing pump's shape to change releasing 2 K

breaks down 1 mol of ATP -> ADP and phosphate
---- uses the E released to bring 2 K ions into cell and export 3 Na ions

in cytoplasm, when nerves stimulated ->es increase in Na+ on one side, need to restore b/c impulse won't go
net (loss/gain) movement of mols from regions high free E to regions LOW free E due to KE of the diffusion mols
pure water -> ? in relation to free E
pure water highest degree of order -> in contact w/ other water mols ->

> order = > free energy
if + solutes to water -> ?
->es more entropy (disorg) -> decrease free E

---->>> water w/ solutes less free E than pure H20
diffusion of H20

: higher free E to lower free E

: osmosis across a cellular membrane, how things move in/out of cell if soluble
water balance in living cells: isotonic
relative to cell, free E of water same on either side of membrane

->es no net movement H20, wnat cells to be like this
water balance in living cells: hypertonic (outside)
cell will lose water to enviro,
: enviro = >er solute

--> free E of water less than inside of cell

--> animal cells: shriveled
--> plant cells plasmolyzed, less pressure
water balance in living cells: hypotonic (outside)
cell will gain water from external enviro

- cell has >er solute than external fluid

-> free E H20 less on side of cell than external

--> water goes in cell-> swells
ex: plants wilt, don't explode b/c cell wall
cell's membrane plays active roll in the cells
regulating metabolic activities, esp prokaryotic
roles carb in cell membrane
cell to cell recognition

name tags
physiology and function of cell membrane depnds on ?
6 functions of cell membrane proteins
signal transduction
cell to cell recognition
intercellular joining
attachment to cytoskeleton and extracellular matrix ECM
function of cell membrane protein: transport
- spans membrane -> hydrophilic selective solute

- hydrolize ATP as E source, pump substances -> membranes
function of cell membrane protein: enzymatic
- active site exposed to substances in adj. solution

- sometimes org. as group carries out sequential steps of metabolic pathway
function of cell membrane protein: signal transduction
- binding site w/ specific shape -> specific chem messenger ex: hormone

- messenger (signal) -> shape change in proteins, sneds message inside cell
function of cell membrane protein: intercellular joining
- adjacent cells hooked together in diff junctoins
function of cell membrane protein: cell to cell recognition
- glycoproteins = ID tags recog'd by other cells
-carb attached to protein
function of cell membrane protein: attachment to cytoskeleton and extracellular matrix (ECM)
- proteins bound to cytoskel elements --> maint cell shape, fixes loca. some mem. proteins

- proteins bound to ECM -> coordinate extracellular/intra changes
each molecule moves ___ but group mol's moves in a ___
diffusion requires E T?F
pure water
highest degree of order, has greatest free E
cell getting rid of waste
cell drinking