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Human Physiology Bio 340 > chapter five membranes > Flashcards

chapter five membranes Flashcards

1
Q

equilibrium & homeostasis

A

NOT the same thing

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2
Q

plasma membrane

A

control of material exchanges, mediation of cell environment interactions

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3
Q

what does the plasma membrane help us understand?

A

how things get from inside to outside and outside to inside through the layer (membrane)

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4
Q

diffusion

A

movement of a substance from high substance concentration to low substance concentration due to random thermal molecular motion, NO energy (cannot have energy input)

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5
Q

kinetic energy

A

molecules are moving, absolute zero will get molecules to stop moving, kinetic energy never stops

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6
Q

factors affecting diffusion of a substance across a membrane

A

temperature (directly), molecular weight (inversely), surface area (directly), gradient (directly), membrane permeability (directly), distance (inversely)

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7
Q

gradient

A

difference between stuff inside vs outside the cell, no gradient = no diffusion

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8
Q

flux

A

amount of substance that crosses a defined surface area per unit time (diffusion per time), time matters, matters in how quickly things diffuse

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9
Q

diffusion equilibrium

A

state in which the diffusion fluxes in opposing directions are equal, resulting in a new flux of zero, membrane is a barrier from the inside cell to the outside cell and we need to get things across

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10
Q

passive transport

A

no energy, diffusion directly through membrane (proteins are facilitated)

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11
Q

channels

A

move things, but limited to small things

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12
Q

what allows for the close of the channel?

A

proteins ability to flex (changing shape)

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13
Q

open channel (leak channel)

A

remain open most of the time although can close occasionally for brief periods

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14
Q

gated channel

A

closed most of the time or regulate by the cell, will momentarily open based on gradients & diffusion

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15
Q

what are the three types of gated channels?

A

stimulus-gated (ligand gated), voltage gated, mechanosensitive

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16
Q

stimulus-gated (ligand gated)

A

respond to ligand binding (neurotransmitters, hormones)

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17
Q

ligand

A

anything that binds to a protein and causes a response

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18
Q

voltage gated

A

respond to changes in membrane potential (action potentials) (electrical state of cell)

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19
Q

mechanosensitive

A

respond to physical pressure or distortion (tactile)

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20
Q

what kind of bonds to ligands bind in?

A

weak bonds (hydrogen bonds, ion bonds)

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21
Q

carrier-mediated transport

A

transmembrane, but will never be open to both sides of the membrane at the same time, never create a continuous pathway, can take in slightly larger things than channels

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22
Q

glucose carriers

A

too big to fit through a channel

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23
Q

saturation

A

putting more ligands, which increases gradient, does not change the speed of the protein

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24
Q

uniport carriers

A

only transport one kind of substance (substrate), concentration gradient determines which way it will move

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25
Q

cotransporters

A

move two or more substances

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26
Q

symport carriers

A

move two or more substances in the same direction across a membrane

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27
Q

antiport carriers

A

cotransporters move two or more substances in opposite directions across a membrane

28
Q

having a substance go directly through a membrane, a channel or carrier is possible by what?

A

diffusion

29
Q

active transport

A

requires energy

30
Q

primary active transport (pump)

A

4 types of ion ATPase (requires ATP energy): sodium-potassium pump, calcium pump, hydrogen pump, hydrogen potassium pump

31
Q

sodium-potassium pump

A

maintains membrane potential (antiport), known as basal metabolism, 3:2 ratio (3 sodium out, 2 potassium in)

32
Q

calcium pump

A

plasma membrane and organelles (uniport)

33
Q

hydrogen pump

A

mitochondria and plasma membranes (kidney) (uniport)

34
Q

hydrogen potassium pump

A

plasma membrane (stomach, responsible for stomach acid) (antiport)

35
Q

secondary active transport

A

moves things against their gradient (uphill), how body absorbs glucose

36
Q

concentration gradient

A

small, non-charged & non-polar substances pass between phospholipids (in middle where it is most hydrophobic, urea & gasses wiggle way through membrane)

37
Q

what are most molecules in the body?

A

lipophobic and/or charged and will not pass readily through the bilayer

38
Q

vesicular transport

A

not using a pump, but moving a cytoskeleton, can move big things into a cell

39
Q

endocytosis

A

process of bringing something in

40
Q

what are the two parts of endocytosis?

A

phagocytosis, pinocytosis

41
Q

phagosytosis

A

cell eating, bringing the cell in

42
Q

pinocytosis

A

cell drinking

43
Q

exocytosis

A

process of going out of the cell

44
Q

osmosis

A

diffusion of water, movement of water from an area of high water (low solute) concentration to an area of low water (high solute) concentration due to random thermal molecular motion

45
Q

solution =

A

solute + solvent

46
Q

osmotic pressure

A

pressure that must be applied to oppose osmosis

47
Q

osmolarity

A

concentration of a solution expressed as number of solutes per liter (regardless of solute type) (can use to compare anything in the world)

48
Q

a normal cell =

A

300 mOsm

49
Q

tonicity

A

describes the volume of change of a cell when placed in a solution

50
Q

what are the two rules of tonicity?

A
  1. always comparing a solution to a normal human cell
  2. the solute must be impermeable (solute cannot get across the membrane)
51
Q

crenate

A

cell shrinks

52
Q

hypertonic

A

causes cell to break

53
Q

cells don’t often get dunked into beakers of solutes so why is osmosis important?

A

we change the solute concentration of the cell as nutrients come into the body through channels or carriers creating a water gradient so food can be digested

54
Q

what is the first rule of electricity?

A

opposites attract

55
Q

how is work performed?

A

when oppositely charged particles come together

56
Q

electrical potential (E)

A

voltage difference between two points (separation of charges)

57
Q

voltage (V)

A

measure of potential (separated charge) to do work (units of potential)

58
Q

membrane potential (Vm or Em)

A

voltage difference between the inside and outside of the cell

59
Q

current (I)

A

movement of an electrical charge (work is being done)

60
Q

Ohm’s Law

A

I = E/R (electrical potential / resistance)

61
Q

resistance

A

whether or not the substances will flow through (permeability)

62
Q

does the material conduct? (equation)

A

g = conductance = 1/R THEN I = gE

63
Q

what is the flow of ions dependent on?

A

how big the gradient is and is the membrane permeable

64
Q

equilibrium potential (Ex)

A

the voltage that would exist across a membrane if it were exclusively permeable to one ion in which voltage force is equal and opposite to concentration force

65
Q

what happens if membrane potential and equilibrium potential are the same?

A

there is no driving force for that ion, they are zero

66
Q

what happens if membrane potential and equilibrium potential are different?

A

there has to be a driving force to create a flux

Human Physiology Bio 340 (6 decks)

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