Electrochemical gradients

Question 1

what are cell membranes made up of

Answer 1

glycerophospholipids
bilayer
prevents movement of charged molecules

Question 2

how does the cell membrane prevent the movement of charged molecules

Answer 2

extremely high resistance to the passage of current
gases and small amphiphilic compounds can diffuse easily

Question 3

3 types of membrane proteins that enable charged molecules to cross the membrane

Answer 3

gap junctions
electrical synapses
membrane transporters

Question 4

gap junctions

Answer 4

large pores that from between adjacent cells
can pass ions and small molecules

Question 5

electrical synapses

Answer 5

specialised form of gap junctions

Question 6

membrane transporters

Answer 6

integral membrane proteins that mediate facilitate diffusion or active transport
aka pumps

Question 7

2 forms of active transport

Answer 7

primary
secondary

Question 8

primary active transport

Answer 8

utilises an energy source

Question 9

secondary active transport

Answer 9

uses the ion gradients established by primary active transport processes

Question 10

3 types of membrane transporters

Answer 10

uniports
symports
antiports

Question 11

uniport

Answer 11

transports single molecule

Question 12

symports

Answer 12

moves multiples molecules in the same direction

Question 13

antiports

Answer 13

move multiple molecules in opposing directions

Question 14

channels

Answer 14

allow water or ions to flow rapidly through a water-filled pore

Question 15

key properties of channels

Answer 15

represent a direct connection between intra and extra cellular spaces
move small molecules
always move charged molecules down concentration gradient
passive
dissipate concentration gradients
extremely high speed

Question 16

pumps

Answer 16

never any connection between intra and extra cellular spaces
can move larger molecules
by using ATP anti ports can move molecules against their concentration gradients
build up concentration gradients
slower

Question 17

what is membrane potential

Answer 17

difference in electrical potential between the interior and exterior of a biological cell

Question 18

typical membrane potential value

Answer 18

+40mV to -70mV

Question 19

Vm

Answer 19

potential difference
movement of one positive ion from the outside to the inside results in +2mV change in Vm

Question 20

depolarisation

Answer 20

movement to a more positive membrane potential

Question 21

hyperpolarisation

Answer 21

movement to a more negative membrane potential

Question 22

inside of cell

Answer 22

more negative than the extracellular environment
due to cells permeability to certain ions and the numbers of those ions

Question 23

Na+ intra and extra cellular concentration

Answer 23

E;145
I: 12

Question 24

K+ intra and extra cellular concentration

Answer 24

E: 4
I: 120

Question 25

Cl- intra and extra cellular concentration

Answer 25

E: 110 I: 15

Question 26

Ca2+ intra and extra cellular concentration

Answer 26

E: 2.5 I: 0.0001

Question 27

principle intracellular cation

Answer 27

potassium

Question 28

principle extracellular cation

Answer 28

sodium

Question 29

principle anion

Answer 29

chloride mainly extracellular

Question 30

resting potential

Answer 30

no active stimulus

Question 31

equilibrium potential across cell membrane

Answer 31

0

Question 32

mammalian neurone equilibrium potentials for Na+ and K+

Answer 32

Na= +60 K= -88

Question 33

calculating the reversal potential for an ion

Answer 33

using the Nerst equation

Question 34

calculating the reversal potential for a mammalian neutron at 37 degrees

Answer 34

Question 35

resting potential

Answer 35

-70mV sodium potassium pump uses ATP to move 3 Na+ out and 2K+ in creates negativity inside of the cell leaky potassium channels to allow the K+ to diffuse out cell is said to be polarised

Question 36

action potential generation

Answer 36

in the presence of a stimulus sodium channels open sodium ions move into the cell and the membrane is said to be depolarised -70 to +40

Question 37

when does an action potential occur

Answer 37

threshold potential

Question 38

what happens when the threshold potential is reached

Answer 38

action potential is generated opens all sodium channels more sodium ions move into the cell action potential moves along the entire length of the membrane until the entire membrane is depolarised

Question 39

increasing Vm past the threshold

Answer 39

can cause action potential in certain tissues like nerves

Question 40

repolarisation

Answer 40

once action potential is generated the Na+ close and K+ open allows K+ to move out of the cell and recreates negativity inside the cell

Question 41

hyperpolarisation

Answer 41

if membrane potential becomes more negative than the resign membrane potential no new action potential can be generated

Question 42

refractory period

Answer 42

no new action potential can be generated

Question 43

how does the cell return to resting potential l

Answer 43

sodium potassium pump

Question 44

hypokalaemia

Answer 44

more potassium ions leak out of the cell during resin state changes membrane potential to more negative value of -90

Question 45

efflux of positive ions

Answer 45

cell membrane will become hyper polarised

Question 46

influx of positive ions

Answer 46

cell becomes depolarised generate action potentia l

Question 47

hyperkalemia

Answer 47

elevated plasma K+ concentration

Question 48

effects of changing K+ concentration

Answer 48

effects the resting potential ability of neurons and muscle cells to reach their action potential

Question 49

increased K+ causes

Answer 49

increased intake decreased renal elimination renal failsure adrenal disease medications that alter kidney function ACE inhibitors ARBs potassium-sparing diuretics NSAIDs increased release from intracellular stores due to tissue damage

Question 50

effects of high potassium on the body

Answer 50

irregular heartbeat chest pain weakening pulse kidney conditions muscle weakeness changes in mood shortness of breath heart palpitations nausea,vomiting and diarrhoea numbness or tingling

Question 51

normal k+ range

Answer 51

3.5-5

Question 52

hyperkalemic value

Answer 52

7

Question 53

what does hyperkalemic value do to the EK value

Answer 53

-90 to -83 cells depolarise RMP closer to action potential cells easily excited

Question 54

most life threatening consequence of hyperkalemia

Answer 54

arrhythmia and/or cardiac arrest due to depolarisation of resting potential cardiac myocytes