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Flashcards in Mitochondrial Bioenergetics Deck (20):
1

How does pyruvate enter the mitochondria?

MPC
Mitochondrial pyruvate carrier

2

PDC (PDH) is activated when:

It is DEphosphorylated

3

Phosphatase Deficiency

PDC is always phosphorylated (inactive). Lactate accumulates leading to lactic acidosis. Mostly affects the CNS.

4

Regulated reactions of the TCA

1. OAA + ACoA --> citrate (citrate synthase)
3. Isocitrate --> a-ketoglutarate (isocitrate DH)
4. a-ketoglutarate --> succinyl-CoA (a-ketogltarate DH)

5

Enzymes of reactions that produce NADH, GTP and FADH2 in TCA

3. isocitrate DH (NADH)
4. a-ketoglutarate DH (NADH)
5. succinate thiokinase (GTP)
6. succinate DH (FADH2)
8. malate DH (NADH)

6

2 major anaplerotic reactins in the TCA

1. Degredation of AAs
2. Carboxylation of pyruvate

7

2-oxoglutaric aciduria

Rare d/o with development delay and neurological problems in infants.
Metabolic acidosis
Microcephaly
Retardation

8

Fumarase deficiency

Severe neurological impairment (fatal within 2 yrs of life).
Encephalomyopathy
Dystonia
Auto rec d/o
Increased urinary excretion of TCA intermediates

9

Mitochondrial depletion syndrome

Hypotonia, dystonia, muscular atrophy, severe sensory impairment.

10

Inhibitors of complex I

Amytal
Rotenone
Myxothiazol
Piericidin A

11

Inhibitor of complex II

Malonate

12

Inhibitor of complex III

Antimycin

13

Inhibitors of complex IV

CO
Cyanide
H2S

14

Inhibitor of complex V

Oligomycin

15

What occurs when the proton gradient is disrupted?

Uncoupling of P ~ ADP from e- transfer
Protons reenter the matrix

16

When protons reenter the matrix:

TCA and O2 production increase
ATP synthase is inhibited
Heat produced

17

Malate-aspartate shuttle

Works in heart, liver and kidneys.
Generates NADH into mito matrix.
NADH joins ETC at complex I.
e- transferred to malate (which enters mito) gives up NADH and converts to aspartated which leaves mito and becomes malate.

18

Glycerophosphate shuttle

Works in muscle and brain.
Generates FADH2 into mito matrix.
FADH2 joins ETC at CoQ

19

Clinical features of mitochondrial diseases (what is affected?)

Nervous system
Eyes
Skeletal muscle
Heart
GI
Renal

20

Metabolic features of mitochondrial diseases (3)

Low energy production
Increased free radical production
Lactic acidosis