Cell Membrane Flashcards

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1
Q

how permeable is the cell membrane?

A

semi/selectively permeable
allows some things in and some things out of the cell

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2
Q

how are the heads and tails in the cell membrane? what is this called?

A

hydrophobic tails
hydrophilic heads
amphipathic

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3
Q

what is the early model of the cell membrane?

A

sandwich membrane:
protein
hydrophilic zone
hydrophobic zone
hydrophilic zone

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4
Q

what is the current and accurate cell membrane model?

A

fluid mosaic model
not rigid
hydrophilic region of protein
phospholipid bilayer
hydrophobic region of protein

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5
Q

what components of the cell membrane are in a mosaic pattern?

A

proteins float randomly in the PLBL

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6
Q

what does the fluid property of the cell membrane allow for?

A

allows the phospholipid to move easily in a lateral direction
the phospholipids can also sometimes flipflop across the membrane

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7
Q

what gives the cell membrane more fluidity?

A

the unsaturated/polyunsaturated hydrocarbon tails that have double bonds

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8
Q

what do the saturated hydrocarbon tails do to the cell membrane?

A

make it more rigid

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9
Q

at room temp, what does adding cholesterol to the cell membrane to it?

A

lowers fluidity, more rigid

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10
Q

what happens if you add cholesterol to the cell membrane at low temp?

A

increases fluidity, prevents phospholipids from clumping

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11
Q

what does the versatility of cholesterol at diff temp allow? ex?

A

allows animals that live in very cold climates to still maintain plasma membrane function
hooves of animals have a lot of cholesterol to prevent freezing when exposed to snow

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12
Q

components of the cell membrane (10)

A
  1. ECM/Glycocalyx
  2. Integral Protein: Transport Protein
  3. Integral Protein: Integrin Protein
  4. Integral Protein: Aquaporin
  5. Cholesterol
  6. Peripheral Protein
  7. Cytoplasm and Cytosol
  8. Phospholipids
  9. Glycoprotein
  10. Glycolipid
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13
Q

where are integral proteins located?

A

span across the phospholipid bilayer

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14
Q

structure of integral proteins

A

alpha helixes (secondary structure)

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15
Q

what do transport proteins do?

A

allow specific molecules to enter or exit the cell

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16
Q

what do integrins do?

A

used for cell communication

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17
Q

where are peripheral proteins found?

A

usually found on the inside ofthe cell membrane

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18
Q

peripheral protein function

A

give strength to cell

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19
Q

what bring the selectively permeable nature to the membrane?

A

hydrophobic/nonpolar tails

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20
Q

what molecules would not be able to get pass the nonpolar tails?

A

ionic/charged molecules, most polar molecules, large molecules

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21
Q

what molecules would easily get past the nonpolar tails?

A

nonpolar, small, gases, steroids

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22
Q

what will the molecules that cannot get past the cell membrane use?

A

use specific transport proteins that have a charged interior

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23
Q

what does water use to enter and exit the cell membrane?

A

transport protein called aquaporin

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24
Q

what is diffusion?

A

tendency for molecules to spread out in an open space
diffuse from a high to low concentration
spontaneous and require no ATP
passive transport

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25
Q

what is osmosis?

A

passive transport of water from high to low concentration across a semi permeable membrane

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26
Q

hypertonic solutions

A

high concentration of solutes in solution

27
Q

hypotonic solution

A

low concentration of solutes in solution

28
Q

isotonic solution

A

same concentration of solutes on both sides

29
Q

what way does water always move? what if it’s isotonic?

A

hypotonic to hypertonic
water still continues to move between the two solutions at equal rate

30
Q

if an animal cell is placed in a hypotonic solution, the cell will?

A

lyse

31
Q

if an animal cell is placed in an isotonic solution, the cell will?

A

stable

32
Q

if an animal cell is placed in a hypertonic solution, the cell will?

A

shrivel

33
Q

if a plant cell is placed in a hypotonic solution, the cell will?

A

turgid/ rigid

34
Q

if a plant cell is placed in an isotonic solution, the cell will?

A

flaccid (limp)

35
Q

if a plant cell is placed in a hypertonic solution, the cell will?

A

plasmolysis - cell membrane pulls away from cell wall

36
Q

which solution do terrestrial animal cells want?

A

isotonic

37
Q

which solution do terrestrial plant cells wanr?

A

hypotonic

38
Q

many terrestrial animal cells are in what type of solution?

A

isotonic

39
Q

what type of solution are protists in?

A

hypotonic environments and must osmoregulate

40
Q

what is osmoregulation? how do protists do it?

A

control their water by balance with the help of contractile vacuoles

41
Q

why do plant cells respond differently than animal cells in a solution?

A

cell wall

42
Q

what is facilitated diffusion?

A

passive transport of a substance across the cell membrane from a high to low concentration, but requires a transport protein

43
Q

what is active transport?

A

require ATP as it goes from low to high concentration
uphill reaction that goes against the concentration gradient

44
Q

good example of active transport?

A

Na-K

45
Q

how many and in which direction are the sodiums and postassiums going?

A

3 Na+ out, 2 K+ in

46
Q

what is a membrane potential/electrochemical gradient?

A

idea that all cells have voltage on each side of the plasma membrane

47
Q

charge of inside of cell? outside

A

inside - negative
outside - posotive

48
Q

what does the differing charges of the cell interior and exterior do?

A

favors cations to come into a cell and anions to exit the cell

49
Q

what are animals main pump? plants?

A

animal - Na-K pump
plant - proton pump

50
Q

what do proton pumps do?

A

actively pump H+ ions out of cells from a low to high concentration

51
Q

potential energy from what can be used to transport other substances across the membrane?

A

energy generated by transmembrane solute gradients can be harvested by the cell
a substance that is actively transported across a membrane can do work as it diffused back by facilitated diffusion

52
Q

what is cotransport ex?

A

a plant cell actively pumps H+ out of a cell
H+ then leaks back into cell passively by facilitated diffusion through a transport protein
brings back with it small sugars, amino acids, or nutrients

53
Q

how do large molecules enter or exit a cell? is this active or passive transport?

A

endo/exocytosis; active

54
Q

large molecule entering cell

A

endocytosis

55
Q

large molecule existing cell

A

exocytosis

56
Q

cell takes in food

A

phagocytosis

57
Q

cell takes in fluid

A

pinocytosis

58
Q

receptor-mediated endocytosis

A

very specific
proteins on the outside of a cell bind to a specific molecule

59
Q

general term for any molecule (usually small) that binds to something (other a receptor)

A

ligand

60
Q

what does receptor- mediated endocytosis allow?

A

allows a cell to take in more substances that in normally would, even if the substance in is low concentrations outside the cell

61
Q

ex of receptor-mediated endocytosis

A

cholesterol is acquired by cells this way

62
Q

how can transport proteins respond to change in the extracellular environment? ex

A

with active transport
if a cell has enough Na+, a transport protein can slow/shut down the active pumping of the molecule up the concentration gradient

63
Q

what does not depend on if the cell has enough of a substance unlike transport proteins?

A

diffusion
passive transport