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bio 112 > chapter 7 > Flashcards

chapter 7 Flashcards

membrane

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1
Q

does facilitated diffusion require energy

A

no

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2
Q

what molecules aid in facilitated diffusion

A

carrier or channel proteins

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3
Q

aquaporin

A

it is a hydrophilic channel in the protein that helps molecules get through by osmosis

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4
Q

how do carrier proteins bring molecules into the cell

A

carrier protein changes shape to transport solutes (glucose to pancreas membrane)

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5
Q

what is active transport

A

when a molecule goes against a concentrated gradient (low conc to high conc)

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6
Q

what does active transport require that passive doesn’t

A

active:
requires energy (ATP)
must be a carrier protein
allows cells to maintain different concentration levels

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7
Q

what is the sodium potassium pump

A

pumps 3 Na cations out of the cell and 2 K cations into the cell. Requires energy

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8
Q

binding of K+ triggers what?

A

release of phosphate

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9
Q

what is the role of a phosphate group in the S-P pump?

A

it allows the protein changes and releases Na+ out of the cell and removing the phosphate and returning to the original shape

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10
Q

the binding of Na+ stimulates what?

A

ATP hydrolysis

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11
Q

what side determines the charge of the cell membrane

A

cytoplasm side

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12
Q

what can cause the membrane to be potentially negative?

A

unequal distribution of ions across the membrane, more negative ions on the inside of the cell

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13
Q

movement of ions across the membrane is dependent on what two forces?

A

chemical force and electrical force

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14
Q

what is chemical force?

A

ions concentration gradient

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15
Q

what is electrical force?

A

effect of membrane potential on the ions movement

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16
Q

what is electrochemical gradient?

A

combined forces of chemical and electrical

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17
Q

net negative charge inside a cell and net chemical gradient favors what?

A

movement of Na+ into the cell

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18
Q

what is proton pump?

A

continually pushing protons against gradient from inside of the cell to the outside

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19
Q

the proton pump is used by which organisms?

A

plants, fungi, and bacteria

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20
Q

the sodium potassium pump is used by which organisms?

A

animals

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21
Q

is the proton pump active or passive transport?

A

active bc it requires energy

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22
Q

where does the proton pump get its energy for its transport

A

the ATP potential energy is stored in membranes to be used when need be

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23
Q

what is cotransport

A

the additional energy from the proton pump pushes the H+ and sucrose into the cell.

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24
Q

how is ATP involved in cotransport

A

ATP is indirectly providing the energy necessary for cotransport (sucrose)

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25
Q

exocytosis

A

large molecules exited by fusion of molecules to the plasma membrane

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26
Q

endocytosis

A

the cell takes in new biological molecules and forming new vesicles from the plasma membrane

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27
Q

phagocytosis

A

cell engulfs a particle of food or bacteria via pseudopodium to form a food vacuole

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28
Q

pinocytosis

A

cell gulps droplets of extracellular fluid into tiny vesicles

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29
Q

how is food digested

A

lysosome

30
Q

receptor mediated endocytosis

A

enables cells to acquire bulk quantities of specific substances

31
Q

ligand

A

molecule that binds specifically to a receptor site of another molecule

32
Q

familial hypercholesterolemia

A

inherited disease characterized by very high cholesterol levels in the blood

33
Q

tonicity

A

the ability of a solution surrounding a cell to cause that cell to gain or lose water

34
Q

free water

A

crosses selectively permeable membrane

35
Q

bound water

A

attached to hydrophilic parts of the solute molecules (sphere of hydration)-doesn’t cross membrane

36
Q

osmosis

A

movement of water molecules across a selectively permeable membrane

37
Q

does osmosis require energy

A

no

38
Q

how does water move in a solute concentration

A

water moves from an area of lower to higher solute concentration

39
Q

equilibrium

A

solute molecules continue to cross membrane but at a similar rate in both directions

40
Q

Does diffusion require energy

A

no

41
Q

what is diffusion

A

the movement of a substances down its concentration gradient by random thermal

42
Q

what is passive transport

A

is one mechanism that moves molecules across cells

43
Q

what is considered “the edge of life”

A

plasma membrane

44
Q

what is selective permeability

A

allows some substances to cross more easily than other substances

45
Q

are organelles selective permeable?

A

yes

46
Q

fluid-mosaic model

A

currently the most accurate model to explain the structure of the plasma membrane

47
Q

how does the membrane represent “fluidity”

A

composed of a fluid phospholipid bilayer

48
Q

what allows cells to maintain unique internal environments

A

selective permeability of a plasma membrane

49
Q

how does the membrane represent “mosaic”

A

proteins are embedded or attached to the phospholipid bilayer

50
Q

what is the dynamically structured mosaic model

A

current model that emphasizes on mosaicism rather than fluidity. Membranes are more packed with proteins than originally thought

51
Q

how are membranes held together

A

WEAK hydrophobic interactions

52
Q

why does the plasma membrane need to be flexible

A

for things to be able to get through

53
Q

why can some proteins move across the plasma membrane

A

some proteins can’t move because they are rigidly attached to the cytoskeleton and some aren’t so they are more free

54
Q

what are the differences in saturated and unsaturated membranes

A

at low temps,
saturated hydrocarbons solidify
unsaturated hydrocarbons stay fluid

55
Q

what prevents hydrocarbons from solidifying

A

double bonds

56
Q

what is cholesterol’s involvement in membranes

A

at low temps: keeps fluidity

at high temps: less fluid

57
Q

why is fluidity important for membranes

A

need to be fluid for molecules to get through, but not too fluid to lose shape

58
Q

how do enzymes move through membranes

A

they move laterally

59
Q

which types of proteins reach both outsides of the membrane

A

both, integral and peripheral proteins

60
Q

integral proteins

A

cross the plasma membrane (hydrophobic/philic regions)

61
Q

peripheral proteins

A

attached to the inner surface of the membrane some times via integral proteins

62
Q

how is the plasma membrane supported

A

attachments to cytoskeleton (microfilaments) on cytoplasmic side

63
Q

what does the plasma membrane attach to on the extracellular side, via the protein

A

collagen fibers and proteoglycans (which are attached to fibronectin)

64
Q

what are the 6 major functions of the membrane proteins

A 
transport
enzyme activity 
signaling transduction
cell to cell recognition
intercellular joining
attachment to cytoskeleton and ECM
65
Q

membrane carbohydrates

A

usually short-branched polysaccharides (15

66
Q

glycolipids

A

lipids with carbohydrates covalently attached

67
Q

glycoproteins

A

proteins with carbohydrates covalently attached

68
Q

where are glycoproteins and glycolipids found

A

within membranes

69
Q

How does a transmembrane glycoprotein become embedded within plasma membrane

A

components of these membranes are synthesized within the ER

70
Q

Where are phospholipids and glycoproteins modified

A

Golgi

71
Q

what molecules move easily through the plasma membrane and why

A

molecules are non-polar and hydrophobic. They don’t need aid of membrane proteins

72
Q

what molecules move difficultly through the plasma membrane and why

A

polar molecules because it is troubled in the hydrophobic environment

bio 112 (14 decks)

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