Chapter 7: Membrane Structure and Function Flashcards Preview

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Flashcards in Chapter 7: Membrane Structure and Function Deck (60)
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1
Q

plasma membrane

A

boundary that separates living cell from its surroundings

2
Q

most abundant lipid in membrane

A

phospholipids

3
Q

amphipathic

A

contains hydrophilic (head) and hydrophobic (tail) regions

4
Q

fluid mosaic

A

membrane is fluid structure with mosaic of protein

5
Q

who discovered the fluid mosaic model

A

singer and nicolson

6
Q

what type of studies supported fluid mosaic model

A

freeze-fracture

7
Q

as temp cools what happens to membrane

A

becomes less fluid, more solid; membrane can solidify

8
Q

which types of membranes are more fluid

A

rich in unsaturated fatty acids

9
Q

function of cholesterol in membrane

A

prevent membrane from becoming too solid when cold, too lquid when warm

10
Q

why do variations of lipid composition of membrane occur

A

adaptations to environment

11
Q

peripheral proteins

A

bound to surface of membrane, sticks out on one side

12
Q

integral proteins

A

penetrate hydrophobic core (transmembrane)

13
Q

glycolipid

A

has carbohydrate chain instead of hydrophilic head

14
Q

glycoproteins

A

carbohydrate chain bonded to protein

15
Q

6 functions of membrnae proteins

A

transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to cytoskeleton and extracellular matrix

16
Q

external carbohydrates may vary among

A

species, individuals, and cell types

17
Q

HIV requires what to enter cell

A

CD4 and CCR5 receptors

18
Q

why are some individuals resistant to HIV

A

do not have CCR5 receptors

19
Q

assymetrical distribution of proteins, lipids,and carbs in membrane determined when

A

membrane is built by ER and golgi bodies

20
Q

hydrophobic molecules can

A

dissolve in lipid bilayer and pas through membrane

21
Q

what type of molecules do not cross through membrane easily

A

polar molecules

22
Q

transport proteins

A

allow passafe of hydrophilic substances across membran; specific to a substance

23
Q

two types of transport proteins

A

channel, carrier

24
Q

channel protein

A

have hydrophilic channel that certain molecules/ions can use s tunnel

25
Q

aquaporins

A

channel protein for water

26
Q

carrier protein

A

bind to molecules, change shape, brins molecules into cell

27
Q

diffusion

A

tendency for moecules to spread out evenly into available space

28
Q

diffusion in relation to concentration gradient

A

diffuses down gradient

29
Q

osmosis

A

diffusion of water across selectively permeable membrane

30
Q

tonicity

A

ability of surrounding solution to cause cell to gain or lose water

31
Q

osmoregulation

A

control of solute concentration and water balance

32
Q

paramecium are hypertonic to environment; how do they maintain homeostasis

A

contractile vacuole

33
Q

cell wall prevents

A

lysing

34
Q

turgid

A

when no more water can diffuse into the cell (in a hypotonic solution)

35
Q

flaccid

A

limp (in an isotonic solution)

36
Q

plant cell in a hypertonic solution

A

cells undergo plasmolysis - plant wilts

37
Q

facilitated diffusion

A

transport proteins speed passive movement of molecules across membrane

38
Q

facilitated diffusion makes use of

A

channel proteins

39
Q

ion channels

A

gated channels for specific ions

40
Q

active transport

A

moves sustances against gradient, allows cell to maintain gradient different from enviroment

41
Q

active transport requires

A

energy

42
Q

examples of active transport

A

sodium-potassium pumps

43
Q

membrane potential

A

voltage difference across a membrane created by difference in distribution of anions and cations across a membrane

44
Q

electrochemical gradient drives

A

diffusion of ions across a membrane

45
Q

electrogenic pump

A

transport protein that generate voltage across a membrane

46
Q

electrogenic pump in animals

A

sodium-potassium

47
Q

electrogenic pump in plants,fungi, bacteria

A

proton pump

48
Q

electrogenic pumps help store

A

energy that can be used for work

49
Q

cotransport

A

when active transport of a solute indirectly drives transport of other solutes

50
Q

example of cotransport

A

plants use H+ gradient generated by proton pump to drive active transport of nutrients into cell

51
Q

small molecules/water tracel through membrane via

A

protein

52
Q

large molecules cross membrane in bulk via

A

vesicle

53
Q

bulk trnaspsort requires

A

energy

54
Q

exocytosis

A

transport vesicles outside cells - secretory cells

55
Q

endocytosis

A

cells takes in mecromolecules by forming vesicles from membrane

56
Q

types of endocytosis

A

phagocytosis, pinocytosis, receptor-mediated

57
Q

phagocytosis

A

cell eating - large molecules

58
Q

pinocytosis

A

cell drinking - smalll molecules

59
Q

receptor-mediated

A

recognizes/bonds to substance that is needed; binding of ligand triggers vesicle formation

60
Q

ligand

A

molecule that bonds to receptor