Energy Production: Carbs

Question 1

What is pyruvate converted to for entry into TCA? What enzyme does this?

Answer 1

Pyruvate -> Acetyl CoA
Via pyruvate dehydrogenase (PDH)

Question 2

Give some examples of what PDH is regulated by

Answer 2

Activated by: Pyruvate, CoA, NAD+, Insulin
Inhibited by: Acetyl-CoA, NADH, ATP, Citrate

Question 3

Why is O2 essential for TCA cycle despite the TCA cycle being an anaerobic process?

Answer 3

TCA cycle is coupled with the electron transport chain, where O2 is the terminal electron acceptor - if electron transport chain stops, so does TCA cycle

Question 4

Where does electron transport chain happen?

Answer 4

Across the inner membrane of the mitochondria

Question 5

How is the proton motive force used?

Answer 5

Protons can only move down the electrochemical gradient, back into the mitochondrial matrix via ATP synthase.

Question 6

Does 1 mol of NADH or FADH2 lead to more ATP synthesis in the ETC?

Answer 6

NADH leads to 2.5 moles of ATP
FADH2 leads to 1.5 moles of ATP

Question 7

How do inhibitors block ETC?

Answer 7

Prevents acceptance of electrons by O2

Question 8

How do uncouplers work?

Answer 8

Increase the permeability of mitochondrial inner membrane to protons. Protons cross the membrane and energy is released as heat instead of being used to drive ATP synthesis

Question 9

Where is brown adipose tissue found?

Answer 9

Newborn infants (around vital organs) for heat generation for body temp maintenance

Question 10

What uncoupling protein naturally occurs in brown adipose tissue?

Answer 10

UCP1 is found in brown adipose tissue. It uncouples ETC from ATP synthesis and the energy from PMF is released as heat instead