Week 4

Question 1

Where is NADH produced within the mitochondria

Answer 1

In the matrix

Question 2

Briefly explain stage IV, oxidative phosphorylation, through its 2 steps

Answer 2

1. Electron transport chain
   - extract energy from e- carriers
2. Chemiosmosis
   - use that energy to resynthesize ATP

• pump H+ across a membrane
  
  • create electrochemical gradient
  • flow of H+ through ATP synthase

Question 3

Outline the metabolic energy transformations of the phosphagen system

Answer 3

Chemical energy bonds of substrate (PCr) transform into chemical energy bonds of ATP

Question 4

Outline the chemical energy transformations of glycolysis/CAC

Answer 4

Chemical energy bonds of substrate (glucose) transform into chemical energy bonds of intermediate molecules which transform into chemical energy bonds of ATP

Question 5

What do we get out of the glycolysis stage

Answer 5

ATP (substrate level phosphorylation): 2
NADH/FADH2: 2 NADH
ATP (oxidative phosphorylation): 0

Question 6

What do we get out of the prep phase stage

Answer 6

ATP (substrate level phosphorylation): 0
NADH/FADH2: 2 NADH
ATP (oxidative phosphorylation): 0

Question 7

What do we get out of the citric acid cycle stage

Answer 7

ATP (substrate level phosphorylation): 2
NADH/FADH2: 6 and 2
ATP (oxidative phosphorylation): 0

Question 8

What do we get out of the ETC + chemiosmosis stage

Answer 8

ATP (substrate level phosphorylation): 4
NADH/FADH2: 0
ATP (oxidative phosphorylation): 30 ATP/NADH and 4 ATP/FADH2

Question 9

What is the total THEORETICAL yield of ATP we get per glucose?

Answer 9

38 ATP/glucose

Question 10

Why is the actual yield of ATP 28-32 per glucose?

Answer 10

• some H+ flow through uncoupling proteins instead of ATP synthase
• some energy is lost as heat instead of captured in ATP
• UCPS are regulated to allow a certain amount of protein leak

Question 11

What are some key events in the oxidative phosphorylation stage of aerobic metabolism?

Answer 11

1. Delivery of electrons to the ETC
2. Electron transport and conversion of O2 to H2O
3. Creation of a proton gradient
4. ATP resynthesis

Question 12

review page 10 - aerobic metabolism II to get lipids and proteins as fuel substrates

Question 13

Describe proteins as fuel substrate

Answer 13

• break polypeptides into amino acids
• strip amino acids to hydrocarbon skeleton by removing nitrogen
  
  • deamination or transamination
    
    • requires lots of water
• different amino acids feed nicely into pathways at diff places (pyruvate, acetyl CoA, CAC intermediates)
• variable ATP yield per amino acid
  
  • overall almost identical to glucose per gram
• we regularly oxidize dietary protein but we dont usually oxidize stored protein