1. Link Reaction and the Kreb’s Cycle

2. Figure Conversion of pyruvate to acetyl CoA, the junction between glycolysis and the Krebs cycle

3. Structure of Acetyl Coenzyme A
CoA Serves to chemically activate acetyl group for transfer
Coenzyme A is a good leaving group (again, facilitates transfer of acetyl group)
You can see from the structure below why we abbreviate this as CoA!

4. Inputs Outputs S—CoA 2 ATP C O CH3 2 Acetyl CoA 6 NADH O C COO
Fig. 9-UN6
Inputs
Outputs
S—CoA 2
ATP
C O
CH3 2
Acetyl CoA 6
NADH
O C COO
Citric acid
cycle
CH2 2
FADH2
COO 2
Oxaloacetate

5. Figure 9.11 A closer look at the Krebs cycle (Layer 1)

6. Figure 9.11 A closer look at the Krebs cycle (Layer 2)

7. Figure 9.11 A closer look at the Krebs cycle (Layer 3)

8. Figure 9.11 A closer look at the Krebs cycle (Layer 4)

9. Figure 9.12 A summary of the Krebs cycle

10. Link to Krebs cycle animation (Smith College)
Link to Krebs cycle Campbell’s

11. Link to Summary of Aerobic Respiration

12. Oxidative Phosphorylation
Electron Transport and Chemiosmosis

13. Fig. 9-13 NADH 50 2 e– NAD+ FADH2 2 e– FAD Multiprotein complexes  40
FMN
FAD 
Fe•S
Fe•S Q

Cyt b
Fe•S 30
Cyt c1 IV
Free energy (G) relative to O2 (kcal/mol)
Cyt c
Cyt a
Cyt a3 20 e– 10 2
(from NADH
or FADH2)
2 H+ + 1/2 O2
H2O

14. Electron transport chain 2 Chemiosmosis
Fig. 9-16 H+ H+ H+ H+
Protein complex
of electron
carriers
Cyt c V Q
 
ATP synthase 
2 H+ + 1/2O2
H2O
FADH2
FAD
NADH
NAD+
ADP + P
ATP i
(carrying electrons
from food) H+ 1
Electron transport chain 2
Chemiosmosis
Oxidative phosphorylation

15. INTERMEMBRANE SPACE H+ Stator Rotor Internal rod Cata- lytic knob ADP
Fig. 9-14
INTERMEMBRANE SPACE H+
Stator
Rotor
Internal
rod
Cata-
lytic
knob
ADP + P
ATP i
MITOCHONDRIAL MATRIX

16. Link to electron transport
Link to Summas
Link to ATP synthease Roto animation
Link to McGraw-Hill Oxidative Phosphorylation
Link to Harvard

17. Cyanide poisoning Link to Summas Cyanide poisoning
Link to what happens when you run out of oxygen
Link to Summas

18. Fig. 9-17 Citric acid cycle CYTOSOL Electron shuttles span membrane
MITOCHONDRION
2 NADH or
2 FADH2
2 NADH
2 NADH
6 NADH
2 FADH2
Glycolysis
Oxidative
phosphorylation:
electron transport
and
chemiosmosis 2
Pyruvate 2
Acetyl
CoA
Citric
acid
cycle
Glucose
+ 2 ATP
+ 2 ATP
+ about 32 or 34 ATP
About
36 or 38 ATP
Maximum per glucose:

19. Figure 9.19 The catabolism of various food molecules

21. Metabolism of Proteins

22. Beta Oxidation of Fatty Acids
Triacyglyercols are broken down into 2 Carbon Acetyl-CoA molecules and fed into Krebs cycle.
Link to Beta Oxidation (Campbells)
Link to 2 C beta oxidation
Note: A 16 carbon fatty acid would be broken down into 16÷2 = 8 CoA segments.
Excellent overview of Beta oxidation

23. 27) You are a doctor and a male patient comes to you with the following symptoms:
1) Complains of low energy (easily fatigued)
2) Blood tests reveal higher than normal levels of lactate.
3) Tests reveal that the patient’s mitochondria can only utilize fatty acids and amino acids for respiration.
Of the following, which is the best explanation of the patient’s condition?
A) His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane.
B) His cells contain a chemical that inhibits oxygen use in his mitochondria.
C) His cells lack the enzyme in glycolysis that forms pyruvate.
D) His cells have a defective electron transport chain, so glucose goes to lactate instead of acetyl CoA.

24. Figure 9.20 The control of cellular respiration