Practical E

Question 1

What are the properties of the outer/inner membrane of the mitochondria?

Answer 1

Outer: permeable to all substances. Phospolipase. Fatty acid elongation
Inner: regulation of the transport of substances

Question 2

What occurs in the intermembrane space?

Answer 2

Nucleotide metabolism. Transanimation of amino acids

Question 3

What occurs in the Inner Matrix?

Answer 3

Fatty acid oxidation. Citric cycle

Question 4

Why is the cristae of the inner membrane important?

Answer 4

Site of electron transport. Oxidation of coenzymes coupled with the reduction of water

Question 5

What instrument is used to measure the consumption of oxygen? How?

Answer 5

The oxygen elctrode. Determines the percentage saturation of oxygen in the mixture
Voltage applied through solution. Resulting current is proportional to the concentration of oxygen

Question 6

What does the Clarke elctrode comprise of ?

Answer 6

Cathode, platinum. Annonde, Silver, silver chrloide
Eletrode bathed in KCl solution
Reaction mixture separated from elctrodes by oxygen permeable, teflon membrane

Question 7

What reactions occur the annode/cathode?

Answer 7

Cathode: O2 + 4e- —-> 2 water (reduction)
Annode: 4Ag+4Cl——> 4AgCl + 4 e-

Question 8

How is the oxygen elctrode calibrated?

Answer 8

Calirated against a buffer saturated with 100% Oxygen

Question 9

What is the procedure for using a Clarke electrode?

Answer 9

Buffer and substrate is allowed to equilibrate
Mitochondrial preparation added
Consumption of O2 measured
ADP and inh, if any, added
Oxygen consumption measured till no further reaction

Question 10

What is NADH reoxidised by

Answer 10

Complex I. Reduction of complex.