1. RECAP Photosynthesis produces: Oxygen Sugar (glucose)
How will these substances be used to make ATP for the organism?

2. Cellular Respiration
Chemical bond energy in food molecules is converted to a form that can be used by the cell (ATP)

3. Energy stored in food is measured in calories
Fats store more energy per gram than do carbohydrates and proteins

6. Cellular Respiration may be:
Anaerobic: doesn’t require oxygen
Aerobic: requires oxygen

7. Anaerobic Respiration
Makes a small amount of usable energy without using oxygen
Reactions occur in cytoplasm
Produces 2 ATP per glucose molecule

8. Takes place in yeast, and bacteria
Can also occur in human muscle cells if no oxygen is present.

9. Anaerobic Respiration
Glycolysis: (sugar is “split”)
Glucose is only partially broken down
Not all of it’s stored energy is released
C6H12O ATP → 2 pyruvic acid ATP
(6-carbon) (3-carbon)
Net gain of energy is 2 ATP
Are produced
Needed to start

11. What Happens to Pyruvic Acid?

12. What happens to Pyruvic Acid?
Fermentation of Alcohol
(Oxygen not present)
C6H12O6 → Ethyl Alcohol + CO2 + 2ATP
Happens in Yeast
Pyruvic acid (from split glucose) is turned into ethyl alcohol and CO2 (carbon dioxide)

13. Useful in the brewing and baking industries
Produces alcohol
Produces carbonation
Bubbles of CO2 make bread rise

14. What happens to Pyruvic Acid?
Fermentation of Lactic Acid:
(Oxygen not present)
C6H12O6 → Lactic Acid + 2ATP
Happens in some bacteria
Pyruvic acid (from split glucose) becomes lactic acid
Used to make cheese, yogurt and buttermilk

15. GLYCOLYSIS
Alcohol Fermentation
Lactic Acid Fermentation

16. Let’s Try This Activity: Finger “Crunches”
As fast as possible crunch your fingers 100 times

17. Lactic Acid buildup in human muscle cells
During intense exercise, if oxygen is not present, human muscle cells use anaerobic respiration to produce some energy, yielding lactic acid
Lactic acid builds up
Muscles eventually cramp up (burning feeling)

18. Oxygen Debt:
Eventually Lactic acid goes to your liver where it is changed back into glucose which can be used again.
In order to convert the lactic acid, your body needs oxygen

20. When You Die

21. Anaerobic Respiration

22. Glycolysis happens in cytoplasm
To produce more ATP, (if oxygen present) reactions must take place in the Mitochondria

23. Mitochondria Structure

25. Aerobic Respiration Makes more ATP using oxygen Occurs in mitochondria
Most eukaryotic organisms carry out aerobic respiration
Plants also carry out respiration!!!

26. Glucose gets completely broken down to release energy
Releases more energy than anaerobic respiration (more energy efficient)
Most of the CO2 and H2O you exhale is produced from aerobic respiration
C6H12O6 + O2 → CO2 + H2O + 36 ATP

27. Aerobic Respiration Summary

28. 3 Steps of Aerobic Respiration
Step 1: Glycolysis
Same as in anaerobic respiration
Doesn’t require oxygen
Takes place in cytoplasm
Glucose is split producing 3-carbon pyruvic acid
Also produces NADH from NAD+
This “carries” some high energy electrons and H+
Net production of 2 ATP

30. Step 2: Kreb’s Cycle (Citric Acid Cycle)
Requires oxygen
Pyruvic acid from glycolysis enters mitochondria
Reactions occur in mitochondrial matrix
Produces high energy electron/hydrogen carriers
NADH and FADH2 (called coenzymes)
These molecules carry “H+” and high energy electrons
These will be used later to help produce more ATP
Produces CO2 gas
Produces 2 ATP

31. Aerobic Respiration Summary

32. Step 3: Electron Transport Chain
Requires oxygen
Occurs on inner membrane of mitochondria
Uses high energy electrons and H+ to convert ADP to ATP
Uses the NADH/FADH2 from glycolysis & Krebs cycle
Final electron & hydrogen acceptor is oxygen (which then becomes H2O which is released)
Produces 32 ATP!!!
Produces H2O

33. Animation of Electron Transport Chain
Note that Oxygen is the final electron acceptor and accepts 2 H+ to become water!

34. Respiration Animation

35. Anaerobic Phase
Doesn’t need O2
Aerobic Phase
Needs O2

36. Efficiency of Cellular Respiration
Anaerobic: Yields 2 ATP per glucose
End products of fermentation still contain a lot of unused potential energy
Meets energy needs of simple organisms
Aerobic: Yields 36 ATP per glucose
More efficient
45% of the energy available in glucose is transferred to ATP where it can do further work for the cell
Note: Car engines only converts about 25% of the energy from gasoline

37. Respiration of Fats and Proteins
Get broken down and converted into amino acids, glycerol and fatty acids
These can enter respiration pathway at different points
Fats yield twice as much ATP as glucose
Proteins yield about the same as glucose but are not the preferred energy source for the cell

38. Evolution of Cellular Respiration
First life originated when there was hardly any oxygen in the atmosphere.
(Probably prokaryotes with few organelles and no
mitochondria)
Glycolysis was the first biochemical process to evolve
Happens in cytoplasm and no oxygen needed.

39. Comparing Photosynthesis and Cellular Respiration
How are these two processes related to each other?
In a typical plant cell describe the way energy is obtained and utilized through both photosynthetic and respiration processes.
Include the materials that need to be taken in and released

40. Comparing Photosynthesis and Respiration