1. Chapter 9: Cellular Respiration

2. Nutrition Energy in most food originally comes from the sun
2 ways to get food
Autotrophs(a.k.a Producers)
Make their own food
Uses photosynthesis or chemosynthesis
Examples: plants, algae, some bacteria
Heterotrophs or Consumers
Cannot make their own food
Take in food by eating
Examples: animals, protists, fungi, most bacteria

3. Cell Respiration Occurs in ALL living organisms
Process in which mitochondria break down food molecules (sugars) to produce ATP
3 stages occur in cellular respiration: glycolysis, Krebs cycle, and electron transport chain

4. If Oxygen is not present
Glycolysis
If Oxygen is present
If Oxygen is not present
Aerobic Respiration
Fermentation

5. Overview of Cellular Respiration
Electrons carried in NADH
Electrons carried
in NADH and
FADH2
Pyruvic acid
Glucose
Glycolysis
Cytoplasm
Cellular respiration is the process that releases energy by breaking down food molecules in the presence of oxygen. Glycolysis takes place in the cytoplasm. The Krebs cycle and electron transport take place inside the mitochondria.
Mitochondrion
Copyright Pearson Prentice Hall

6. Aerobic Respiration Occurs in the mitochondria Yields 36 ATP molecules
3 steps of aerobic
respiration

7. Glycolysis
Makes only 2 ATP and 2 pyruvates (pyruvic acid)

8. Glycolysis Glucose is broken in to 2 pyruvates!
Occurs in the cytoplasm
Glycolysis only creates 2 ATP
Advantages of Glycolysis??
The process of glycolysis is so fast that cells can produce thousands of ATP molecules in a few milliseconds.
Glycolysis does not require oxygen.

9. Krebs Cycle (a.k.a. Citric Acid Cycle)
Breaks down pyruvates (which means it continues breaking down the glucose that entered glycolysis)
Produces: citric acid, 2 ATP, CO2

10. Electron Transport Chain
Produces 34 ATP
Converts ADP to ATP using ATP synthase

11. Cellular Respiration Song
Total ATP Production for
Aerobic Respiration
1 glucose molecule  38 ATP
2 from glycolysis
36 from Krebs cycle and Electron Transport Chain
Cellular Respiration Song

12. Anaerobic Respiration
Fermentation  occurs in the absence of oxygen (2 kinds)
Alcoholic Fermentation  yeasts (fungi), plants
Produces carbon dioxide gas and ethyl alcohol
Ex: wine, beer, breads

13. Lactic Acid Fermentation
Performed by animals and bacteria
In humans:
Transferred from muscles (occurs in muscle cells)
Produced during strenuous activity/exercise
Results in muscle soreness
In bacteria:
Used to make the following foods: yogurt, buttermilk, cottage cheese, sour cream

14. No additional ATP molecules are produced in fermentation
Only 2 ATP produced from glycolysis and anaerobic respiration

15. Ch. 9 Bell Ringer: Identify which phrase describes the following:
lactic acid fermentation alcoholic fermentation
________ important in baking bread
________ builds up in muscles after a few seconds of intense activity
________ the reasons why runners breathe heavily after a race
________ involved in making beer and wine
2. What is the net energy gain in glycolysis?
a. 4 ATP b. 2 ATP c. 36 ATP d. 38 ATP

16. Photosynthesis vs. Cellular Respiration
What does it do?
Makes glucose
Breaks down glucose
Why do it?
To store energy
To release energy
Who does it involve?
“green organisms”, some bacteria, algae, plants
ALL organisms
When does it occur?
The day into night
All the time
Where does it occur?
Chloroplasts
Starts in the cytoplasm
Ends in the mitochondria in the presence of O2
Equation for process
6CO2 + 6H2O + light  C6H12O6 + 6O2
C6H12O6 + 6O2  6CO2 + 6H2O + ATP
Exchange of gases
Takes in CO2 and gives off O2
Takes in O2 and gives off CO2