5) Energy Production: Carbs 3

Question 1

How is Pyruvate dehydrogenase (PDH) regulated?
linking Glycolysis to TCA cycle

Answer 1

ACTIVATED BY:
Pyruvate
CoA
NAD+
ADP
Insulin
Dephosphorylation

INHIBITED BY:
Acetyl coA
NADH
ATP
Citrate
Phosphorylation

Question 2

Link Equation

Answer 2

Pyruvate to Acetyl- CoA
NADH produced per pyruvate
In matrix of mitochondria
PDH large enzyme complex
Coenzymes come from vit B1, very important
irreversible, key regulatory step.

Question 3

How much energy and reducing power is produced from TCA cycle?
How much energy and reducing power produced overall from one glucose molecule?

Answer 3

3NADH +
FADH2 +
GTP +
produced from TCA
(X2 for per glucose)

IN TOTAL:
+2 ATP from glycolysis
+2 ATP (technically GTP) from TCA
Reducing power:
+2NADH from glycolysis
+2NADH from link equation
+6NADH from TCA
+2FADH2 from TCA
4ATP, 10 NADH, 2 FADH2 net produced per glucose
4+ (10x2.5) + (2x1.5) = 32 ATP net produced total after oxidative phosphorylation

Question 4

Brief overview of Oxidative Phosphorylation

Answer 4

Between the mitochondrial matrix and the intermembrane space, we establish a protein gradient. This gradient is used to transfer energy into ATP, from reductive power. The inner mitochondrial membrane stops protons leaving the intermembrane space. The matrix becomes much more negative, the intermembrane space much more positive. We force all the protons from the matrix to intermembrane space via proton translocating complexes attaches to inner mitochondrial membrane. These complexes do this using energy from the electrons released from NADH and FADH2. The process of generating the proton gradient is coupled with the ATP synthase protein. This protein lets H+ ions back into the matrix, turning a ‘rotor’ in the process, this mechanical energy is used to phosphorylate ADP.

Question 5

uncoupling of ETC

Answer 5

Uncouplers increase permeability of mitochondrial inner membrane to protons,
if permeable to protons, they can escape gradient without generating ATP. This means all energy is put towards heat. DNP, a toxic pesticide, is an example of a dangerous decoupler. It is used in diet pills.
Brown adipose tissue uses uncoupling by fatty acids in non shivering thermogenesis.