1. Cellular Respiration

2. Chemical Energy and Food
PHOTOSYNTHESIS
___________ + _________ + ___________ →_______________ + __________
6 CO2
6 H2O
C6H12O6
6O2
CELLULAR RESPIRATION
C6H12O6
6 CO2
_____________ + _________ →________ + __________ + __________
6O2
6 H2O
The two equations are exact opposites!
Discovery School - The Mitochondria (2:44)

3. Comparing Photosynthesis & Cellular Respiration:
Which type(s) of organisms carry out photosynthesis?
Autotroph Heterotroph
Which type(s) of organisms carry out cellular respiration?

4. Organisms that do CELLULAR RESPIRATION:
Bacteria
Protists
Fungi
Plants
Animals
In short – almost ALL organisms undergo cellular respiration (also known as AEROBIC RESPIRATION)!

5. EXCEPT FOR…
SOME bacteria, who undergo a similar process called ANAEROBIC RESPIRATION, which does NOT require oxygen.
Instead, this process may use nitrate, sulfate, or carbonate…
HOWEVER, it does not result in as much ATP production as when oxygen is used

6. Energy (Adenosine triphosphate)
Reactants
Products
O C6H12O6 → CO H2O + ATP
Oxygen
Carbon Dioxide
Water
Glucose/sugar
Energy (Adenosine triphosphate)
Yields/ produces
Cellular respiration is the process that releases energy from food in the presence of oxygen.

7. Structure of the Mitochondria:

8. Chemical Energy and Food
Cellular respiration happens slowly and in many steps.
If all the energy was release in one step… Most would be lost as light and heat!
Cellular respiration breaks down glucose molecules and banks their energy in ATP

9. Chemical Energy and Food
Unit for measuring energy in food = Calorie
1 Calorie = 1 kilocalorie = 1,000 calories
Energy Consumption - Virtual Cell Animation (4:41)

10. Anaerobic Vs Aerobic Respiration
Anaerobic Respiration
Does NOT require oxygen
Makes less ATP (than aerobic)
Ex:Glycolysis
Aerobic Respiration
Requires oxygen
Makes more ATP
Ex: Krebs cycle and electron Transport chain

11. 3 Stages of Cellular Respiration
Glycolysis
Krebs Cycle (Citric Acid Cycle)
Electron Transport Chain (ETC)

12. Glycolysis ATP (Glykos = sweet, Lysis = split apart)
The first step in cellular respiration
Happens in the CYTOPLASM outside the mitochondria
Does not require oxygen, BUT it needs some energy to get it started.
What molecule is going to supply the energy?
ATP
Glycolysis Overview - Virtual Cell Animation (3:00)

13. Glycolysis Reactions - Virtual Cell Animation (5:00)
Produces pyruvic acid (pyruvate = 3-carbon compound)
Cell needs to invest some energy to get a higher return (2 ATP gained)
Occurs quickly, in milliseconds to respond to increased energy demand
Produces 2 NADH
Glycolysis Reactions - Virtual Cell Animation (5:00)

14. Put in 2 ATP and get back 4 ATP
Glycolysis
________ ↓
___________ → → _____________
____________________ + _______________
GLUCOSE
2 PYRUVIC ACID
ATP ATP ATP ATP
NADH NADH
Put in 2 ATP and get back 4 ATP
Net gain of 2 ATP and 2 NADH

15. The Advantages of Glycolysis
Glycolysis produces ATP very fast, which is an advantage when the energy demands of the cell suddenly increase.
Glycolysis does not require oxygen, so it can quickly supply energy to cells when oxygen is unavailable.

16. Mitochondria Structure
Has a double membrane, with an intermembrane space between the two layers.
Cristae are folds of the inner membrane
The matrix is the innermost compartment, which is filled with a gel-like fluid.

17. Citric Acid Cycle An Overview (3:17)
The Krebs Cycle
2nd stage of cellular respiration
also known as the Citric Acid Cycle (The Krebs Cycle is because citric acid is the first compound formed in this series of reactions.)
Citric Acid Cycle An Overview (3:17)

18. The net yield from the Krebs cycle
Cellular Respiration
The net yield from the Krebs cycle
six CO2 molecules
two ATP
eight NADH
two FADH2.

19. KREBS CYCLE
KREBS CYCLE PRODUCES
____ 3 1 1 4
Krebs Cycle Animation

20. Electron Transport Chain
Final step in the breakdown of glucose
Where occurs across the inner membrane of the mitochondria.
Energy Yield Total of 32 ATP
H2O
NAD+
NADH
ATP H+
Controlled release of energy for synthesis of ATP
Electron transport chain 2 O2
2e + 1
Electron Transport Chain (2:00)

21. Overview of Cellular Respiration

22. Cellular Respiration Glycolysis, Krebs cycle, Electron Transport (6:01)

23. Fermentation When pyruvic acid moves to the next step,
if there is no oxygen = anaerobic
if there is oxygen = aerobic

25. Fermentation
Fermentation – process by which cells release energy in the absence of oxygen
Glycolysis produces ATP quickly and does not require O2
Without O2 the ETC does not run – no where for NADH to deposit its electrons
Without NAD+ the cell cannot keep glycolysis going and ATP production stops.

26. Two types of fermentation:
Alcoholic Fermentation
Lactic Acid Fermentation

27. Alcoholic Fermentation
Occurs in yeast cells:
Yeast is added to bread– CO2 produced in fermentation make air spaces in bread and therefore bread rises.
Alcohol evaporates during cooking
Alcohol is toxic to cells. If too much fermentation occurs, alcohol will kill yeast cells.
Happens when:
Yeast make beer
Bacteria make wine
How Stuff Works - Bread (2:35)
How Stuff Works - Whiskey (2:32)

28. Lactic Acid Fermentation
Happens in muscles during exercise when body can’t get oxygen to tissues fast enough.
Lactic acid builds up in muscles causing soreness.
Bacteria use lactic acid fermentation to make: yogurt, cheese, sour cream, pickles, sauerkraut

31. The Totals Cellular Respiration (aerobic: with oxygen)
1 glucose → 36 ATP
Fermentation (anaerobic: without oxygen)
1 glucose → 2 ATP