Catabolism of glucose

Question 1

NADPH + H

Answer 1

Oxidised form

Question 2

NADP+

Answer 2

Reduced form

Question 3

NAD+

FAD

Answer 3

Reduced form

Question 4

Negative modulators

Answer 4

ATP
Citrate
H+

Question 5

Positive modulators

Answer 5

AMP

Fructose 2,6-bisphosphonate

Question 6

Glycolysis reduces NAD+ to what?

Answer 6

NADH + H+

must be re-oxidised to let glycolysis continue

Question 7

What is regenerated through the metabolism of pyruvate?

Answer 7

NAD+

Question 8

Which complex catalyses the oxidative decarboxylation of pyruvate to acetyl-CoA

Answer 8

pyruvate dehydrogenase complex

Question 9

Main determinant of glucose oxidation in well oxygenated tissues

Answer 9

Pyruvate dehyrdrodgenase complex (converts pyruvate into acetyl coA)

Question 10

Where are the enzymes of the TCA cycle located?

Answer 10

Mitochondrial matrix (except succinate dehydrogenase, which is in the inner mitochondrial membrane)

Question 11

Control of the TCA cycle

Answer 11

High ATP, NADH and acetyl-CoA means plenty of energy

High ADP and NAD+ means lack of energy

High succinyl-CoA and acetyl-
CoA means plenty of precursor molecules for biosynthetic reactions

Question 12

From each turn of the TCA cylce

Answer 12

3 x NADH + H+
1 x FADH
1 x GTP
2 x CO2

Question 13

How can the phosphoryl transfer potential be measured?

Answer 13

Phosphoryl transfer potential can be measured by the free energy change, DGo’, for the hydrolysis of ATP

Question 14

How can the electron transfer potential be measured?

Answer 14

Measured by the redox potential (or reduction potential), E’o, of a compound

Question 15

Where do electrons from NADH enter the respiratory chain?

Answer 15

Complex I

Question 16

Where do electrons from FADH enter the respiratory chain?

Answer 16

Complex II

Question 17

What is transport of the electrons through the respiratory chain coupled to?

Answer 17

Transfer of electrons through the respiratory chain is coupled to transport of H+ from the mitochondrial matrix to the intermembrane space

(complex 2 does not pump H+)

Question 18

How do protons flow back through?

Answer 18

Flow back through ATP synthase

Question 19

This part of subunit protrudes into mitochondrial matrix

Answer 19

F1

Question 20

Hydrophobic complex of the inner membrane

Answer 20

F0

Question 21

Inhibition of oxidative phosphorylation

Answer 21

Electron transport chain can be inhibited at many stages

Cyanide, azide, and CO inhibit transfer of electrons to O2

No proton gradient can be formed

No ATP can be synthesised

Question 22

PO ratio

Answer 22

Number of molecules of Pi incorporated into ATP per atom of oxygen used

Question 23

How does NADH made in glycolysis enter cross the mitochondrial matrix?

Answer 23

glycerol-3-phosphate and malate shuttle

Question 24

1 glucose molecule yields how many ATP molecules?

Answer 24

30-32

Question 25

OXPHOS disease

Answer 25

Involve components of oxidative phosphorylation
Common degenerative diseases
Mutations in mitochondrial or nuclear genes required for normal oxidative phosphorylation
Pathology usually becomes worse with age
initially, a small number of normal mitochondria may provide enough ATP
with age, spontaneous mutations accumulate
at some point, not enough ATP can be generated
Symptoms usually appear in tissues with highest ATP demands
nervous system, heart, skeletal muscle, kidney

Question 26

The brain accounts for how much of total oxygen use?

Answer 26

20%