Electrochemical Gradients

Question 1

What is a semi-permeable membrane?

Answer 1

A layer through which only allowed substances can pass

Question 2

What is black film?

Answer 2

Phospatidylserine mixed and spread onto glass or plastic plates with pin holes
Submerged into hydrophilic solution
Appears black as light is reflected black

Question 3

What molecules can pass through a lipid bilayer easily?

Answer 3

Hydrophobic molecules e.g. O2, CO2, N2, benzene

Question 4

What molecules can pass through a lipid bilayer quite easily?

Answer 4

Small uncharged polar molecules e.g. H2O, Urea, Glycerol

Question 5

What molecules can pass through a lipid bilayer but very slowly?

Answer 5

Large uncharged polar molecules e.g. Glucose and Sucrose

Question 6

What molecules can not pass through a lipid bilayer?

Answer 6

Ions

Question 7

What is passive transport dependant on?

Answer 7

Permeability and concentration gradient

Question 8

Why are transport processes so important?

Answer 8

Maintain ionic composition and intracellular pH
Regulate cell volume
Expels waste products and toxic substances
Generates ion gradients for electrical excitability of nerves and muscles
Concentration of metabolic fuels and building blocks

Question 9

What is ping pong transport?

Answer 9

molecule goes in one side, it then closes that side and opens the other side

Question 10

How is facilitated diffusion by ion channels different to just channels?

Answer 10

Something must bind to it to open e.g. ACh or ATP

Question 11

What kind of plot shows km and vmax accurately?

Answer 11

Lineweaver Burke plot

Question 12

If Delta G is positive what does this mean?

Answer 12

Active process

Question 13

If Delta G is negative what does this mean?

Answer 13

Passive process

Question 14

What does active or passive transport depend on?

Answer 14

Concentration ratio

Membrane potential

Question 15

What does active transport allow?

Answer 15

The transport of ions or molecules against an unfavourable concentration or electrical gradient
Uses energy from ATP hydrolysis

Question 16

Is there more Na inside or out of the cell?

Answer 16

Outside

Question 17

Is there more Cl inside or out of the cell?

Answer 17

Outside

Question 18

Is there more Ca inside or out of the cell?

Answer 18

Outside

Question 19

Is there more K inside or out of the cell?

Answer 19

Inside

Question 20

What is a primary active transporter?

Answer 20

Uses ATP directly e.g. Ca ATPase

Question 21

What is uni-transport?

Answer 21

only one molecule transported at a time

Question 22

What is a uniport?

Answer 22

One molecule transported in one direction

Question 23

What is symport?

Answer 23

Two molecules transported in one direction

Question 24

What is Antiport?

Answer 24

Two molecules transported in different directions

Question 25

Where is the Potassium Sodium pump located?

Answer 25

Plasma membrane

Question 26

How many Na and K are moved in Na/K pump?

Answer 26

3Na out 2K in

Question 27

What is responsible for the resting membrane potential of -70mV?

Answer 27

K+ diffusion through channels

Question 28

What are the characteristics of the Ca-Mg-ATPase

Answer 28

High affinity for Ca Low capacity for Ca Mg is just used (does not move)

Question 29

What are the characteristics for the Ca Na exchanger

Answer 29

1 Ca moved out 3 Na moved in Low affinity High capacity

Question 30

What does the Na H exchanger exchange?

Answer 30

Sodium and H+ ions

Question 31

What is the Na-glucose cotransporter?

Answer 31

Symport (2Na and 1 glucose)

Question 32

How does Fluoxetine work?

Answer 32

Outward flow of K+ down its concentration gradient leads to uptake of serotonin in the presynaptic cleft and by platelets with Na ions, inhibits SERT and increases 5-HT action- elation and sticky blood

Question 33

What goes wrong with Cystic Fibrosis?

Answer 33

Cystic Fibrosis Transmembrane conductance regulator- does not pump chlorine out so unbalanced

Question 34

What is the function of the Na/K ATPase pump ?

Answer 34

Forms the Na/K gradient Necessary for electrical excitability Drives secondary active transport (controls pH, regulates cell volume, absorbs Na in epithelia, nutrient uptake)

Question 35

What are high levels of intracellular calcium to a cell?

Answer 35

Toxic

Question 36

What do PMCA and SERCA do?

Answer 36

Primary active transport Expel Ca out of the cell (into ER-SERCA) high affinity, low capacity

Question 37

What does the NCX do?

Answer 37

Secondary active transport Expels intracellular Ca during cell recovery (polarised) 3Na Ca exchanger low affinity, high capacity role in cell toxicity during ischaemia/reperfusion If depolarises reverses mode of operation

Question 38

What does the mitochondrial ca uniport do?

Answer 38

Facilitated difusión | operates at high Ca concentration to buffer potentially damaging Ca concentrations

Question 39

What are the Acid extruders?

Answer 39

Na+/H+ exchanger Na dependent Cl-/HCO3- exchanger Sodium bicarbonate cotransporter

Question 40

What are the base extruders?

Answer 40

Cl-/HCO3- exchanger | Anion exchanger

Question 41

What does the Na/H+ exchanger do?

Answer 41

Na in H out regulates pH and cell volume Activated by growth factors Inhibited by amiloride

Question 42

What are bicarbonate transporters used for?

Answer 42

Cell volume regulation

Question 43

If the cell begins to swell, what occurs?

Answer 43

Extrude ions

Question 44

If the cell begins to shrink, what occurs?

Answer 44

Influx ions

Question 45

How is cell volume regulation achieved?

Answer 45

No standard method | different cells use different combinations of transporters

Question 46

What would occur if filtration occurred on its own?

Answer 46

Na and HCO3- ions would leave the body and H2O would follow so the person would dehydrate Therefore bicarbonate reabsorption at proximal convoluted tube occurs

Question 47

What is the first line treatment of people with hypertension?

Answer 47

Renal control of circulating Na concentration with the water tablet

Question 48

What do Loop diuretics effect?

Answer 48

NKCC2 | Thick ascending limb

Question 49

What do Thiazides effect?

Answer 49

NCCT | Distal convoluted tubule

Question 50

What do Amiloride effect?

Answer 50

ENaC | DCT

Question 51

What do spironolactone effect?

Answer 51

ROMK and CCD