Powering Biology And Redox Potentials

Question 0

Where is the proton gradient created in chloroplasts?

Answer 0

The thylakoid lumen

Question 1

In mitochondria the F1 part of ATP synthase is in which compartment?

Answer 1

The matrix

Question 2

What is osmosis?

Answer 2

The movement of water molecules through a selectively permeable membrane down a water potential gradient

Question 3

What is chemiosmosis?

Answer 3

The movement of ions across a selectively permeable membrane down their electrochemical gradient

Question 4

What is a low effective proton conductance? and when is it needed?

Answer 4

Proton leakage across the membrane. In energy transducing membranes.

Question 5

What is the equation that describes the Gibbs free energy change inside and outside a closed compartment?

Answer 5

G=RT Ln ( A in/A out)

Question 6

What is the gas constant?

Answer 6

8.314 J.K-1.mol-1

Question 7

What is the equation to compare the gibbs free energy associated with charge gradient?

Answer 7

G= N.F. Psi

Question 8

What is the Faraday constant?

Answer 8

96500 J.V-1. mol-1

Question 9

What charge gradients are required for insulin release?

Answer 9

K+ and ca+

Question 10

The equation linking gibbs free energy and pH?

Answer 10

G(p-n)H+= F. Psi.-2.303RT. Delta pH

Question 11

Why does the delta Psi not build up in chloroplasts?

Answer 11

Cotranslocation of Cl- ions or counter translocation of Mg2+

Question 12

Why can the thylakoid lumen require less H+ to cause a greater decrease in pH?

Answer 12

It is alot smaller.

Question 13

What part of the proton motive force powers the H+ Na+ antiporter?

Answer 13

Just the pH component

Question 14

What transporter is only powered by the delta Psi component of the PMF in mitochondria?

Answer 14

calcium transporter

Question 15

what motive force is used to move glucose into the small intestine?

Answer 15

Sodium

Question 16

What makes ATP a good energy source?

Answer 16

It is relatively stable in aqueous solution. The cell also keeps the concentration of ATP-ADP so it is ten magnitudes away from the natural equilibrium

Question 17

Name a common uncoupler?

Answer 17

CCCP-carbonyl cyanide m chloro phenyl hydrazone

FCCP-p-trifluoromethoxy carbonyl cyanide phenyl hydrazone

Question 18

What is the mechanism of bat non shivering thermogenesis?

Answer 18

Uncoupling Protein 1- UCP1. Bypassing ATP synthase. 3 repeats of two transmembrane alpha helices linked by a long hydrophillic loop on the matrix side of the membrane. The alpha helices form a channel for the H+ to pass down.

Question 19

Reduction is?

Answer 19

Gain of electrons

Question 20

Oxidation is?

Answer 20

Loss of electrons

Question 21

The definition of redox potential?

Answer 21

The ability of a molecule to accept or donate electrons.

Question 22

What is the nernst equation?

Answer 22

E=Em + (2.303RT/nF) Log10(ox/red)

Question 23

What is the standard electrode?

Answer 23

H2 at 1 atm, H+ iona at 1 mol.L-1.

Question 24

What is the nomenclature for redox potential at PH7?

Answer 24

E0’

Question 25

What is the order of oxygen reduction to water?

Answer 25

O2, O2-., H2O2, H20 + HO. , 2H20

Question 26

What is the nernst equation?

Answer 26

E=Em + (2.303RT/nF)log10(ox/red)

Question 27

What is the electron potential involving pH?

Answer 27

EmpH= E0 - (2.303RT/F).(M/N).pH

Question 28

What is a normal reference electrode? and the electrode potential of this?

Answer 28

A saturated calomel electrode, Mercury/Mercurous. 0.244V

Question 29

What results in formation of reactive oxygen species?

Answer 29

Slippage in the mitochondrial transfer chain.

Question 30

Where are the major sites of ROS in the electron transfer chain?

Answer 30

NADH dehydrogenase and cytochrome bc1 complex.

Question 31

What is dismutation produces what?

Answer 31

H202 from O2-.

Question 32

What enzyme performs dismutation?

Answer 32

Superoxide dismutase.

Question 33

What happens to H2O2 after it is produced by dismutation?

Answer 33

Reduction by Fe2+ produces a HO- and a HO. (highly reactive). Can also be enzymatically chlorinated to form hypochlorous acid.

Question 34

Reactive oxygen species cause damage to which molecules?

Answer 34

Iron sulpher cluster proteins and DNA. can result in non native disulphide bonds giving protein dysfunction/aggregation.

Question 35

ROS has been linked to which disease states?

Answer 35

cataract formation, macular degeneration, chronic heart failure, carcinogenesis and atherosclerosis.

Mitochondrial dysfunction plays a role in Alzheimer’s, Parkinson’s and Huntington’s

Question 36

What is the major small molecule antioxidant in eukaryotes and gram negative bacteria?

Answer 36

Sulphur containing molecule glutathione

Question 37

What is glutathione made up of?

Answer 37

a tripeptide, glutamate, cysteine and glycine. glutamate linked by side chaine COO-

Question 38

What is the enzyme that maintains levels of reduced glutathione in the cell?

Answer 38

Glutathione reductase

Question 39

What are the primary antioxidants in plants?

Answer 39

Carotenoids.

Question 40

what is the role of thioredoxin?

Answer 40

Maintains reducing environment in the cytoplasm and helps to maintain thiol groups in the reduced state of normal functioning proteins.

Question 41

What is used as the electron donor in maintaining the reduceed forms of antioxidants?

Answer 41

NADPH

Question 42

What do cytochrome P450 enzymes catalyse?

Answer 42

A monooxygenase reaction where one oxygen atom is inserted into a molecule and the other reduced to water. This can result in drug inactivation or activation and herbicide degradation. Also insecticide resistance.

Question 43

What transcription factor in ecoli help to protect from ROS?

Answer 43

OxyR