1. Cellular Respiration
Chapter 9

2. Chemical Energy and Food
Living things get the energy they need from food.
The process of releasing the energy stored in food is cellular respiration.

3. Overview of Cellular Respiration
In the presence of oxygen, aerobic respiration takes place.
This produces 36 ATP per molecule of glucose.
In the absence of oxygen, anaerobic respiration (fermentation) takes place.
This produces 2 ATP per molecule of glucose.

4. Fermentation (without oxygen)
Section 9-1
Chemical Pathways
Glucose
Krebs cycle
Electron transport
Glycolysis
Alcohol or lactic acid
Fermentation (without oxygen)

5. Glycolysis
Both aerobic and anaerobic respiration begin with a process known as glycolysis.
This means “glucose -splitting”
This takes place in the cytoplasm.

6. To the electron transport chain
Glycolysis
Section 9-1
Glucose
2 Pyruvic acid
To the electron transport chain

7. To the electron transport chain
Glycolysis
Section 9-1
Glucose
2 Pyruvic acid
To the electron transport chain

8. To the electron transport chain
Glycolysis
Section 9-1
Glucose
2 Pyruvic acid
To the electron transport chain

9. Glycolysis
If oxygen is available, the pyruvic acid molecules will be broken down further to release more energy.
If oxygen is unavailable, the pyruvic acid molecules will be converted to a waste product with no further release of energy (fermentation).

10. Fermentation (without oxygen)
Section 9-1
Chemical Pathways
Glucose
Krebs cycle
Electron transport
Glycolysis
Alcohol or lactic acid
Fermentation (without oxygen)

11. Fermentation Also known as anaerobic respiration. Two types:
Alcoholic fermentation – in yeasts
Pyruvic acid is converted to alcohol and carbon dioxide.
Lactic acid fermentation – in bacteria and muscle cells
Pyruvic acid is converted to lactic acid.

12. Lactic Acid Fermentation
Section 9-1
Lactic acid
Glucose
Pyruvic acid

13. Aerobic Respiration 6O2 + C6H12O6  6CO2 + 6H2O + 36 ATP
Oxygen + glucose  carbon dioxide + water + energy

14. Mitochondrial Reactions
Mitochondrion
Electrons carried in NADH
Electrons carried in NADH and FADH2
Pyruvic acid
Glucose
Electron Transport Chain
Krebs Cycle
Glycolysis
Mitochondrion
Cytoplasm

15. Flowchart Aerobic Cellular Respiration Glucose (C6H1206) + Oxygen (02)
Section 9-2
Flowchart
Aerobic Cellular Respiration
Glucose (C6H1206) +
Oxygen (02)
Glycolysis
Krebs Cycle
Electron Transport Chain
Carbon
Dioxide
(CO2) +
Water
(H2O)

16. Aerobic Respiration
In the presence of oxygen, pyruvic acid is further broken down to release additional energy.
This takes place in the mitochondria.
There are two steps:
The Krebs Cycle
The electron transport chain

17. The Krebs Cycle Also known as the citric acid cycle.
Pyruvic acid (from glycolysis) is broken down into carbon dioxide.
High energy electrons are captured by NAD and FAD and brought to the electron transport chain.
Net gain of 2 ATP from this cycle.

18. The Krebs Cycle
Section 9-2
Citric Acid Production
Mitochondrion

19. Electron Transport Chain
NADH and FADH2 drop off high energy electrons.
These pass through a series of reactions located on the inner membrane that produce ATP.
Oxygen combines with hydrogen to make water.
Net gain of ATP = 32

20. Electron Transport Chain
Section 9-2
Electron Transport
Hydrogen Ion Movement
Channel
Mitochondrion
Intermembrane
Space
ATP synthase
Inner
Membrane
Matrix
ATP Production

22. ATP totals Glycolysis – 2 Krebs Cycle – 2
Electron Transport Chain – 32
Net: from one glucose molecule = 36 ATP

23. Photosynthesis & Cellular Respiration
Function
Energy capture
Energy release
Location
Chloroplasts
Mitochondria
Reactants
CO2 & H2O
C6H12O6 & O2
Products
CO2 and H2O
Equation
6CO2 + 6H2O  C6H12O6 + 6O2
6O2 + C6H12O6  6CO2 + 6H2O