Aerobic metabolism

Question 1

Where does gluconeogenesis occur?

Answer 1

Liver

Question 2

What are major enzymes of cellular redox?

Answer 2

Flavin adenine dinucleotide and Nicotinamide adenin dinucleotide

Question 3

How many H can FAD and NAD accept?

Answer 3

FAD accepts 2H, NAD accepts 1H

Question 4

What stages are involved in aerobic respiration?

Answer 4

Pyruvate oxidation, TCA cycle, ETC

Question 5

What is the reaction for pyruvate oxidation?

Answer 5

Pyruvate + O2 + NAD+ (pyruvate deydrogenase) –> CO2 + acetyl-CoA + NADH

Question 6

How is the action of pyruvate dehydrogenase regulated?

Answer 6

By PDH complex. PDH kinase inactivates PDH by phosphorylation; PDH kinase active when ATP:ADP is high; PDH kinase inhibited by pyruvate. PDH phosphotase activates PDH by dephosphorylation; PDH phosphotase activated when Ca2+ high (muscular contraction)

Question 7

What is net equation for Krebs?

Answer 7

Acetyl CoA + ADP + Pi + 3NAD+ + FAD +3H2O –> ATP + 3NADH + FADH2 + 2CO2

Question 8

What is the “aim” of Krebs?

Answer 8

All C from original glucose formed in to CO2; traps high energy electrons in reduced coenzymes

Question 9

What occurs during Krebs?

Answer 9

Oxaloacetate (4C) + acetyl-CoA –> citrate (6C) + CoA; citrate (6C) + NAD+ –> 5C molecule + CO2 + NADH; 5C molecule + NAD+ –> succinyl-CoA (4C) + CO2 + NADH; succinyl (4C) –> ATP + succinate (4C); succinate (4C) + NAD+ + FAD+ –> oxaloacetate (4C) + NADH + FADH2

Question 10

What is the overall process that occurs in the ETC called?

Answer 10

Mitochondrial oxidative phosphorylation

Question 11

What occurs within the ETC?

Answer 11

NADH and FADH2 are oxidised, releasing e-s; e-s flow along series of membrane proteins; redox reactions provide energy to actively transport H+ into intermembrane space; H+ gradient is generated, creating a proton motif force; H+ undergoes facilitated diffusion down chemiosmotic gradient through ATPase; proton flow causes rotary motor of ATPase to spin; mechanical energy of spinning motor is captured and combines ADP + Pi –> ATP; O2 + 4e- + 4H+ –> 2H2O

Question 12

How many protons does NADH pump?

Answer 12

10

Question 13

How many protons does FADH2 pump?

Answer 13

6

Question 14

What complexes do NADH supply?

Answer 14

4H+ at complex I; 4H+ at complex III; 2H+ at complex IV

Question 15

What complexes do FADH2 supply?

Answer 15

4H+ at complex II; 2H+ at complex IV

Question 16

Where does oxygen act as final acceptor?

Answer 16

Complex IV (cytochrome C oxidase)

Question 17

What number complex is ATPase?

Answer 17

Complex V

Question 18

What is the absolute net ATP?

Answer 18

+30ATP

Question 19

How many kcal does glucose contain?

Answer 19

720kcal/mol

Question 20

How many kcal does ATP contain?

Answer 20

7.3kcal/mol

Question 21

How many moles of ATP is harvested from 1mole ATP theoretically?

Answer 21

30 ATP per mole glucose

Question 22

How many moles of ATP is harvested from 1mole ATP actually?

Answer 22

26 ATP per mole glucose

Question 23

Why is actual efficiency of ATP production different to theoretical?

Answer 23

Inner membrane leaky to H+: human skeletal muscle ~70% efficient. H+ gradient is used for other purposes, such as facilitating pyruvate transport into mitochondrial matrix from cytoplasm