1. Biology 12 - respiration

2. Cellular respiration Provides energy for the cell Occurs in all cells
Net equation:
glucose + oxygen  carbon dioxide + water + energy (ATP)
Occurs as a series of reactions, involving many different enzymes
Involves anaerobic and aerobic reactions

3. ATP and ADP Act as chemical batteries
Carry and release small amounts of energy
ATP
adenosine
adenosine
phosphate
ADP
energy

4. Anaerobic respiration
Occurs in the cytoplasm
Does not need oxygen
Involves 2 processes – glycolysis and fermentation

5. Glycolysis
Glucose is broken down into 2 pyruvate (pyruvic acid) molecules
Reactions use 2 ATP
Reactions make 4 ATP
Net ATP = 2/glucose molecule

6. Fermentation In animals: Pyruvate is converted to lactic acid
In plants and fungi:
Pyruvate is converted to ethanol and carbon dioxide

7. Aerobic respiration Occurs in the mitochondrion Needs oxygen
Involves Transition reaction, Krebs cycle and Electron transport chain
Involves many reactions and enzymes
Produces 36 ATP
Waste products are carbon dioxide and water

8. Structure of mitochondrion

9. Transition reaction
Pyruvate attaches to Coenzyme A to form Acetyl Coenzyme A
Acetyl Coenzyme A enters mitochondrion and releases the pyruvate into the Krebs cycle
Coenzyme A can also pick up fatty acids and take them into the Krebs cycle

10. Transition reaction

11. Krebs cycle Occurs in the matrix of the mitochondrion
A cycle of reactions generates ATP and hydrogen ions (carried by NAD and FAD carriers to electron transport chain)
Waste product is carbon dioxide
Produces 2 ATP/glucose molecule

12. Krebs cycle

13. Carrier proteins Carry hydrogen ions to electron transport chains
NAD  NADH + H+
FAD  FADH2 + H+

14. Electron transport chain
Found in the cristae (inner membranes) of the mitochondrion
ATP is generated as hydrogen ions are passed down the chain
Oxygen is used up
Waste product is water
Produces 34 ATP/glucose molecule

15. Electron transport chain

16. Summary of reactions

17. Comparison of aerobic and anaerobic respiration
Site it occurs
cytoplasm
mitochondrion
Need for oxygen no
yes
Waste products
Animals – lactic acid
Plants – carbon dioxide and alcohol
Carbon dioxide and water
Amount of ATP
2/glucose molecule
36 – 38/glucose molecule
Reactions involved
Glycolysis
Fermentation
Transition reaction
Krebs cycle
Electron transport chain