1. Ms. Napolitano & Mrs. Haas CP Biology
Cellular Respiration
Ms. Napolitano & Mrs. Haas
CP Biology

2. Recall: The photosynthesis equation is
6CO2 + 6H2O + light  6O2 + C6H12O6

3. Food Food – source of raw material for the cells of the body
Energy source
calorie – amount of energy needed to raise 1 gram of water 1 degree Celsius
Calorie = kilocalorie = 1000 calories

4. Cellular Respiration
Cellular respiration – the process that releases energy by breaking down glucose & other food molecules in the presence of oxygen
The equation for cellular respiration is:
6O2 + C6H12O6  6CO2 + 6H2O + Energy
Look familiar?!?!?!?! 

5. 3 Parts of Cellular Respiration:
Glycolysis
Cytoplasm
Krebs cycle (AKA citric acid cycle)
Mitochondrial matrix
Electron transport chain
Inner mitochondrial matrix

6. PART I
Glycolysis

7. Glycolysis
Glycolysis – process in which one molecule of glucose is broken in half
Produces 2 molecules of pyruvic acid = 3C compound
Anaerobic - does not require O2

8. ATP & NADPH Production
The cell needs to input some energy before more can be produced
2 ATP used up, 4 ATP made = 2 ATP net gain
High-energy electrons are carried by NAD+
Makes NADH
Similar to NADP+ in photosynthesis
Overall glycolysis equation:
glucose  2 pyruvic acid + 2 ATP + 2 NADH

9. PART II
The Krebs Cycle

10. The Krebs Cycle
Recall: 2 pyruvic acid molecules were made during glycolysis
Krebs cycle – pyruvic acid is broken down into CO2

11. Steps of the Krebs Cycle:
1C from pyruvic acid becomes CO2
Other 2C’s joined to a coenzyme to make acetyl-CoA
Acetyl group (2C) is converted to citric acid (4C)
6C compound
Citric acid becomes 4C again
C’s become CO2
ADP  ATP
NAD+  NADH
FAD  FADH2
High-energy electron carriers

12. Final Products of the Krebs Cycle:
8 NADH
2 FADH2
2 ATP
6 CO2

13. The Electron Transport Chain
PART III
The Electron Transport Chain

14. The Electron Transport Chain
The electron transport chain – uses high-energy electrons from the Krebs cycle to convert ADP into ATP

15. Product: H2O e- are passed from one protein to the next
Enzyme at the end combines e- with H+ and O2 to form H2O

16. Product: ATP
When 2e- pass through ETC, energy transports H+ across the membrane
ATP synthase pumps H+ to the other side of the membrane via facilitated diffusion
ATP synthase rotates like a turbine, making ADP + P  ATP

17. Other Stuff!

18. Totals Glycolysis = 2 ATP (net) Krebs cycle + ETC = ~36 ATP
Total = ~38 ATP molecules from 1 glucose molecule!

19. Fermentation
Fermentation – process by which ATP is made in the absence of O2
AKA anaerobic
Goes through glycolysis, then picks a different pathway
Alcoholic fermentation
Alcohol & CO2 is made as wastes
Made by yeast - causes bread to rise
Lactic acid fermentation
Lactic acid is made as a waste
Causes muscle soreness or helps make dairy products

20. Energy & Exercise Quick energy Long-term energy
Only enough ATP in muscles for ~50m sprint (few seconds)
Lactic acid fermentation – ATP made for ~ m sprint (~90s)
Lactic acid removal requires extra O2
Long-term energy
Cell respiration is the only way to make ATP for the long-term
Pace yourself!
Energy stored in muscles as glycogen
Stored glycogen - ~15-20 min of activity, then other energy forms get broken down (ex. fats – weight control!)