10: Ox Phos

Question 1

Three goals of ox phos

Answer 1

1. Transfer electrons from NADH and FADH2 -> O2
2. Establish proton gradient across inner mito membrane
3. Synthesize ATP

Question 2

Standard redox potential (Eo’)

Answer 2

Affinity for electrons (inversely proportional to delta G)

Question 3

Chemiosmotic theory

Answer 3

Electron transfer through respiratory chain leads to pumping of H from matrix to inner-mito space

Question 4

Proton motive force (pmf) two components

Answer 4

PH gradient, membrane potential

Question 5

What generates most ATP in the cell?

Answer 5

Oxphos

Question 6

Three main sources of NADH

Answer 6

1. TCA
2. Pyruvate dehydrogenase
3. Ketone body oxidation

Question 7

Three main sources of FADH2

Answer 7

1. Complex II
2. Glycerol phosphate shuttle
3. FaCoA dehydrogenase

Question 8

Which respiratory chain complex is not coded by any mito DNA?

Answer 8

Complex II

Question 9

What treatment can overcome rotenone poisoning?

Answer 9

Vitamin K3 (menadione)

Question 10

Side affects of nucleoside analogue treatments like AZT, AraC, and ddC

Answer 10

Fatigue, lactic acidosis, myopathy, cardiac dysfunction, hepatic failure

Question 11

F0 and F1 subunits of ATP synthase

Answer 11

F0: membrane-spanning channel
F1: where ATP synthesis occurs

Question 12

Forming 1 ATP requires passage of how many H ions?

Answer 12

3

Question 13

Uncoupling of respiratory chain

Answer 13

H ions leak through UCP1 (thermogenin), disrupting proton gradient -> energy released as heat

Question 14

How is thermogenesis in brown tissue started

Answer 14

Brain senses cold -> symp stimulation to brown adipose -> TAGs broken into FAs -> FAs activate UCP1

Question 15

Common mitochondrial free radical

Answer 15

Ubiquinone radical (partially reduced ubiquinone during e transfer)

Question 16

What do superoxide dismutases do?

Answer 16

Catalyze O2 superoxide + 2H _> O2 + H2O

Question 17

SOD1

Answer 17

Cu/Zn SOD; cytosolic

Question 18

SOD2

Answer 18

Mn/Zn SOD; mitochondrial

Question 19

What enzyme catalyzes hydrogen peroxide into O2 and water?

Answer 19

Catalase

Question 20

Name three common antioxidants

Answer 20

Glutathione, vitamin E, vitamin C

Question 21

Cytochrome P450 superfamily

Answer 21

An e- transport system in the ER that uses NADPH

Question 22

How does hypoxia in MIs cause lactic acidosis?

Answer 22

Lack of O2 -> decreased respiratory chian activity -> cells depend on glycolysis for energy -> lactic acidosis

Question 23

First discovered mito disease

Answer 23

Luft’s disease

Question 24

Luft’s disease symptoms

Answer 24

Perspiration, marked fluid intake with normal urine volume high caloric intake, weakness

Question 25

Primary and secondary causes of mitochondrial diseases

Answer 25

Primary: defect in DNA (mito or nuclear)
Secondary: ischemia, perfusion, CV disease, renal failure, drugs, aging, alcohol, smoking, etc.