Week 4 Lectuure 1/03/24 1

Question 1

Uncoupling proteins

Answer 1

UCP1 found in brown adipose tissue, herniates the most heat
UCP2 AND 3
More widely distributed eg muscle
Thermoregulation

Question 2

Takeaway

Answer 2

ETc generates a proton gradient across the inner mitochondrial membrane ie charge

Protons are allowed back through the inner mitochondrial membrane by the turbine ATP synthase - generating ATP
Ie potential energy or charge is converted into chemical energy (atp)

Uncoupling proteins sit on the inner mitochondrial membrane and allow free passage of H+
•I.e. potential energy (or charge) is converted into HEAT

Question 3

Carbohydrate oxidative aerobic energy yield

Answer 3

Glycolysis
2.Pyruvate dehydrogenase
3.TCA cycle
4.Oxidative phosphorylation

Remember

•Glucose = 2 x pyruvate via glycolysis
•NADH = 2.5 x ATP
•FADH = 1.5 x ATP
GTP = ATP

Answer 4

Glycolysis
NET OF 2 ATP
Used 2 gained 4

Oxidative phosphorylation - 5 atp in the cytosol
NET OF 7
Pyruvate to acetyl = happens in the Matrix

TCA-goes twice as 2 acetyl CoA

Answer 5

Glycolysis = cytosol
2 ATP used
4 ATP gained
2 NADH GAINEED ——— has to carry electrons into matrix of mitochondria
NET = 2 ATP

Pyruvate Acetyl CoA = mitochondria
2 NADH gained

TCA = mitochondria
6 NADH gained
2 FADH gained
2 GTP gained = not quite equivalent of ATP

Question 6

MALATE/ASPARTATE SHUTTLE

Answer 6

Enables the NADH produced in the cytosol (e.g. from glycolysis) to enter the matrix of the mitochondria

•The glutamate/aspartate carrier involves movement of a proton (H+) back into the matrix

•Hence, net = 1 less proton (H+) for ATP synthase for every NADH carried

•1 NADH = net movement of 9 x H+
•9 / 4 = 2.25 ATP instead of 2.5
•X 2 NADH = 0.5 less ATP overall

Question 7

GTP TO ATP (PHOSPHATE CARRIAGE)

Answer 7

Enables the “conversion “ of GTP to ATP

•GTP produced via TCA cycle in the mitochondrial matrix
•Leads to…..ADP phosphorylated to ATP in the cytosol

•Requires phosphate carriage into the matrix, alongside 1 x proton (H+)

•Hence, net = 1 less for proton (H+) available for ATP synthase
•1 GTP → 1 ATP = minus 1 x H+

Question 8

Energy yield

Answer 8

Glycolysis
•+2 ATP directly
•+5 ATP via oxidative phosphorylation
•- 0.5 ATP for aspartate/malate shuttle (2 x H+)

Pyruvate Acetyl CoA
•+ 5 ATP via oxidative phosphorylation

TCA cycle
• + 2 ATP via GTP
•- 0.5 ATP for phosphate carriage (2 x H+)
•+ 18 ATP via oxidative phosphorylation

Total = 31

Question 9

ANAEROBIC CATABOLISM

Answer 9

Glucose + 2 Pi + 2 ADP > 2 Lactate + 2 ATP + 2H2O