Mitochondrial Bioenergetics

Question 1

Is PDC active when phosphorylated or dephosphorylated?

Answer 1

Just like Acetyl CoA Carboxylase, the Pyruvate Dehydrogenase Complex MUST be DEPHOSPHORYLATED for the enzyme to work!!!!!!

Question 2

What happens if the PDC shuttle doesn’t work?

Answer 2

You can’t generate Acetyl-CoA as readily. Lactic Acidosis occurs as the body switches to anaerobic respiration in a means to try to make energy.

*** increase lactate–> increase lactic acid–> increase H+ in blood

Question 3

What phosphorylates or deactivated the PDH Complex?

Answer 3

(-) NADH, (-) ATP, (-) Acetyl CoA –> PHOSPHORYLATION

Question 4

What dephosphorylates/activates the PDH Complex?

Answer 4

(+) NAD+, (+)ADP, (+) Pyruvate, (+) AMP

Question 5

What are the major products of the TCA cycle alone not including the PDC?

Answer 5

3 NADH
1 FADH2
1 GTP

Question 6

What are the energy expenditures for the reduced coenzymes of the TCA cycle?

Answer 6

NADH-2.5ATP
FADH-1.5 ATP
GTP- 1 ATP

Question 7

What is the rate limiting step in TCA Cycle?

Answer 7

ISOCITRATE DEHYDROGENASE

Question 8

What will happen if there is an excess of alpha-ketoglutarate?

Answer 8

It will prohibit ISOCITRATE DEHYDROGENASE, the RATE-LIMITING STEP OF TCA CYCLE!!!!!!!!!!!!!!!!!!!

Question 9

What are the mobile carriers in ETC?

Answer 9

Mobile Carriers include:

1. ) Quinone (Between Complex II and Complex III)
2. ) Cyt C (Between Complex III and IV)

Question 10

Which complexes receive which electrons?

Answer 10

Complex I -> NADH electrons

Complex 2-> FADH2 electrons

Question 11

Oxidative phosphorylation is regulated by which two things?

Answer 11

1. ) 02 levels

2. ) ATP: ADP Ratio

Question 12

Two different types of mitochondrial shuttle systems.

Answer 12

Malate-Aspartate Shuttle System (heart, liver, kidneys)–>
-Uses ATP from glycolysis to reduce OAA to Malate so that it can be shuttled into the mitochondria and regenerated as OAA–> Produces NADH BACK

G3P shuttle system (Brain+ muscle)–>

• Converts the DHAP–>G3P
• Consumes the NADH and produces FADH2
• Result: NET LOSS OF ENERGY EXPENDITURE BECAUSE NADH (2.5 ATP) vs. FADH2 (1.5 ATP)