1. Cell Respiration Chapter 9 Prentice Hall pg. 220-233
9–1 Chemical Pathways
A Chemical Energy and Food
B. Overview of Cellular Respiration
C. Glycolysis
1. ATP Production
2. NADH Production
D. Fermentation
1.Alcoholic Fermentation
2.Lactic Acid Fermentation
9–2 The Krebs Cycle and Electron Transport
A. The Krebs Cycle
B. Electron Transport
C. The Totals
D. Energy and Exercise
1. Quick Energy
2. Long-Term Energy
E. Comparing Photosynthesis and Cellular Respiration

2. How much energy is present in food?
1 gram of glucose (C6H12O6) when burned in the presence of oxygen releases 3811 calories
This process takes place in the mitochondrion of both plants and animals

3. Cellular respiration - the process that releases energy by breaking down glucose and other food molecules in the presence of oxygen (energy trapped in ATP molecules)
Equation:
6O2 + C6H12O6  6CO2 + 6H20 + Energy
Two types of cellular respiration include aerobic (with O2) and anaerobic (without O2)

4. Electron Transport Chain
Aerobic respiration - includes 3 main steps; can remove about 38% of energy from glucose; powers all energy for life; occurs in the cytoplasm and mitochondria
Glucose
Glycolysis
Cytoplasm
Pyruvic acid
Electrons carried in NADH
Krebs Cycle
Electrons carried in NADH and FADH2
Electron Transport Chain
Mitochondrion

5. First Step- Glycolysis
glycolysis - the process by which glucose is converted to pyruvic acid (pyruvate) and energy is released
Products
(net gain) 2 ATP made for energy
2 energy shuttle (NADH) sent to ETC to make ATP
2 Pyruvate will be used to start Krebs Cycle in the mitochondria
Does not require the presence of oxygen (can happen in both aerobic and anaerobic reactions)
Frees 2 % of the energy in glucose
Takes place in the cytoplasm of the cell

6. To the electron transport chain
Glycolysis Review
(net gain) 2 ATP made for energy
2 energy shuttle (NADH) sent to ETC to make ATP
2 Pyruvate will be used to start Krebs Cycle in the mitochondria
Glucose
To the electron transport chain
2 Pyruvic acid

7. Second Step- Krebs cycle
2) Krebs cycle – uses pyruvic acid from glycolysis and releases energy and CO2
Series of energy extracting reactions
named after Hans Krebs, Nobel
prize 1953 (discovery of this step)
also called citric acid cycle
Products
CO2 – exhaled as a waste product (autotrophs use in photosynthesis)
2 ATP made- used for cell’s life processes
8 energy shuttles (NADH, FADH2)- sent to ETC to make ATP
takes place in mitochondrial matrix

8. Third Step- Electron Transport Chain
electron transport- produces 32 ATP from energy shuttles sent from glycolysis and Kreb’s cycle
Products:
Electrons, hydrogen, and energy are added to oxygen to make water
32 ATP made- (90% of ATP made here)
Occurs across
the inner
mitochondrial
membrane

9. Total energy produced from aerobic respiration from 1 glucose = 36 ATP

10. Aerobic Respiration (conclusion)
38 % efficient (some energy lost as heat)
62% is released is heat (one of the reasons why your body feels warmer after exercise)
1 glucose molecule = (yields) 36 ATP made (energy)
ATP made form glucose provides energy to sleep, exercise, eat and study biology (allows our cells to function properly)

11. Shows energy that is made in the ETC from NADH and FADH2 molecules

12. Review of Aerobic Respiration
Glucose (C6H1206) +
Oxygen (02)
Glycolysis
Krebs Cycle
Electron Transport Chain
Carbon
Dioxide
(CO2)
Water
(H2O)

13. Two Kinds of fermentations 1) Alcoholic fermentation
Fermentation – when oxygen is not present (anaerobic), glycolysis is followed by a different pathway; releases energy from food in the absence of oxygen
Organisms live on small amounts of ATP that comes from glycolysis (only 2 ATP per glucose)
Role of fermentation is to recharge low energy molecules so that glycolysis can continue to proceed in the absence of 02
Two Kinds of fermentations
1) Alcoholic fermentation
2) Lactic Acid fermentation

14. (Anaerobic) Alcoholic Fermentation
Characteristic of some yeast and bacteria
Begins with glycolysis and ends with alcohol and CO2
Alcohol is toxic to cells
Causes bread to rise;
yeast in dough runs out of oxygen
begins to ferment, giving off bubbles of CO2
forms the air spaces that you see in a slice of bread
small amount of alcohol produced, evaporates when the bread is baked

15. (Anaerobic) Lactic acid Fermentation
Characteristic of many organisms including animals and bacteria
Pyruvic acid is converted into lactic acid
Lactic acid is produced in your muscles during rapid exercise when the body cannot supply enough oxygen to the tissues
Without enough oxygen, the body is not able to produce all of the ATP that is required
Muscle cells begin to produce ATP by Lactic Acid fermentation
Lactic acid builds up causing soreness, burning and muscle fatigue in animals
Lactic acid can be removed from affected cells and detoxified by the liver
Unicellular organisms also produce lactic acid as a waste product during fermentation
Helps to make cheese yogurt, buttermilk, and sour cream

16. Energy and Exercise Quick Energy(quick race)
Beginning of race bodies uses 3 ATP
Muscles contain only enough ATP for the first few seconds
Past the 50 m mark ATP is gone
Muscles will then need to produce ATP through lactic acid fermentation
Makes enough ATP to last 90 seconds ( m sprint)
Long Term Energy (soccer game~1 hour)
Must go through cell respiration to make enough ATP
Respiration is slower than fermentation (this is why athletes must pace themselves)
Muscles use energy from glycogen (first minutes) and then go to fats for energy
Explains why aerobic exercise is effective for weight loss

17. Comparison of Aerobic vs. Anaerobic Respiration
Glucose
Glycolysis
Krebs cycle
Electron transport
Fermentation
Alcohol
(with oxygen)
Lactic acid
(without oxygen)

18. Glucose
Glycolysis
Kreb’s Cycle
Fermentation
Lactic Acid

19. Comparison of Fermentation to Cellular Respiration
Anaerobic Respiration
Aerobic Respiration
Lactic Acid
Alcoholic
Cellular respiration
glucose
glucose
glucose
glycolysis (pyruvic acid)
glycolysis (pyruvic acid)
glycolysis (pyruvic acid)
carbon dioxide
carbon dioxide
lactic acid
water
alcohol
2 ATP
2 ATP
36 ATP

20. Aerobic Cellular Respiration

21. Comparing Photosynthesis and Cellular Respiration
Energy flows in opposite directions
Photosynthesis “deposits” energy
Cellular Respiration “withdraws” energy
CO2
glucose
glucose
H2O
ATP
mitochondria
light
sun
C6H12O6
ATP
glucose
glucose 36

22. Energy from sun stored in glucose Carbon dioxide taken in
Cellular Respiration
Photosynthesis
Food synthesized
Food broken down
Energy from sun stored in glucose
Energy of glucose released
Carbon dioxide taken in
Carbon dioxide given off
Oxygen given off
Oxygen taken in
Produces sugars
Produces CO2 and H2O
Requires light
Does not require light
Occurs only in presence of chlorophyll
Occurs in all living cells
Comparison of Photosynthesis and Cellular Respiration
Cell Respiration

23. Chloroplast Sunlight Photosynthesis CO2, H2O O2, glucose Mitochondria
Cellular Respiration
ATP +
Heat