1. How Cells Release Chemical Energy
Chapter 7

2. Mitochondria Structure
Organelle of cell respiration
Mitochondria Structure
Cristae or

3. Energy flow in the ecosystem
Relationship of Photosynthesis and Cellular Respiration
Basis of
Energy flow in the ecosystem
p.107d

4. Who can Respire?
p.108

5. Overall Concept of Cellular Respiration
p.106a

6. Fig. 7-2, p.108

7. Energy-Requiring Steps of Glycolysis fructose1,6-bisphosphate
2 ATP invested
Energy-Requiring Steps of Glycolysis
glucose
ADP P
ATP
glucose-6-phosphate P
fructose-6-phosphate
ATP
fructose1,6-bisphosphate P
ADP
PGAL P
Stepped Art
Fig. 7-4, p.111

8. ENERGY-RELEASING STEPS OF GLYCOLYSIS substrate-level phosphorylation
PGAL
PGAL
NAD+
NADH
NAD+
NADH Pi Pi P P P P
1,3-bisphosphoglycerate
1,3-bisphosphoglycerate
substrate-level phosphorylation
ADP
ATP
ADP
ATP
2 ATP invested P P
3-phosphoglycerate
3-phosphoglycerate P P
2-phosphoglycerate
2-phosphoglycerate
H2O
H2O P P
PEP
PEP
ATP
substrate-level phosphorylation
ADP
ADP
ATP
2 ATP invested
pyruvate
pyruvate
Fig. 7-4b, p.111
to second set of reactions

9. Glycolysis review
In cytoplasm
Uses glucose, 2 ATP, 2 NAD
Makes 2 pyruvates, 4ATP, 2NADH
Net gain of ATP=2
Why 10 steps?

10. Acetyl-CoA Formation pyruvate coenzyme A NAD+ (CO2) NADH CoA
Krebs Cycle
CoA
oxaloacetate
citrate
NAD+
NADH
NADH
NAD+
FADH2
NAD+
FAD
NADH
ADP +
phosphate
group
ATP
Fig. 7-7a, p.113

11. Krebs Cycle
Begins after the Intermediate step
Pyruvate Acetyl CoA + CO2 + NADH
Acetyl CoA enters mitochondria matrix and reacts with oxaloacetate Citrate (aka citric acid cycle)
A series of reactions will yield oxaloacetate again (aka cycle)
Each pyruvate makes 3 NADH, 1FADH2, 1ATP, 2 CO2
How many per glucose?

12. Fig. 7-8b, p.114

13. Fig. 7-8c, p.114

14. Electron Transport Chain
Mitochondrial membrane or cristae Enzymes (Cytochromes) and ATP synthase on membrane to shuttle electrons and protons NADH, FADH2 gives up the H H+ + e- Electrons are passed through the membrane proteins and the energy released is used to transport the H to the outer membrane The gradient established is the force needed to allow the H to move back into the inner membrane through ATP Synthase The 4H + 4e + O2 H2O What is the purpose of the oxygen?

15. How many ATP’s was that?
Each NADH can make 3ATP and FADH2 2ATP ____ATP From glycolysis ____NADH from Glycolysis x ___ = ____ATP From Krebs Cycle ____NADH from Krebs cycle x ___ = _____FADH2 from Krebs x _____ = Total ATP ______

16. 2 ATP net 2 pyruvate energy output energy input ATP NADH 2 NAD+
2 ADP
2 pyruvate 4
energy output
energy input
GLYCOLYSIS
ATP
C6H12O6
NADH
2 NAD+
electrons, hydrogen from NADH
2 ethanol
ETHANOL FORMATION
2 acetaldehyde
2 CO2
2 H2O
Stepped Art
Fig. 7-10, p.116

17. Fig. 7-10b, p.116

18. electrons, hydrogen from NADH LACTATE FORMATION
ATP
C6H12O6
NADH
2 NAD+ 2
2 ADP
2 pyruvate 4
energy output
energy input
GLYCOLYSIS
2 ATP net
2 lactate
electrons, hydrogen from NADH
LACTATE FORMATION
Stepped Art
Fig. 7-11, p.117

19. Fig. 7-12a, p.117

20. What is the purpose of anaerobic respiration?
To continue making ATP even in the absence of oxygen
Can happen in glycolysis but soon ..
NADH are used up
Cannot be regenerated in ETC
So has to be regenerated in the fermentation phase of cell respiration
Side effects – formation of ethanol, CO2 or lactate

21. complex carbohydrates
FOOD
fats
glycogen
complex carbohydrates
proteins
fatty acids
glycerol
simple sugars
(e.g., glucose)
amino acids
NH3
carbon backbones
glucose-6-phosphate
urea
PGAL 2
ATP
glycolysis 4
ATP
(2 ATP net)
NADH
pyruvate
Acetyl-CoA
NADH
CO2
NADH,
FADH2
Krebs
Cycle 2
ATP
CO2 e–
ATP
ATP
ATP
many ATP H+
fats
e– + oxygen
Fig. 7-13b, p.119

22. Uses of Cell Respiration?
ATP for cell work
CO2 for photosynthesis
Carbon skeletons for metabolism of sugars, lipids, proteins, nucleic acids, etc.