1. Photosynthesis & Cellular Respiration
Chapter 9 Summary—
**The stuff you REALLY need to know**

2. What is photosynthesis?
The process by which autotrophs trap energy from sunlight with chlorophyll and use this energy to convert carbon dioxide and water into simple sugars.

3. Which organisms carry out photosynthesis?
Plants
Algae
Photosynthetic bacteria

4. Where does photosynthesis take place?
Chloroplasts
Thylakoid membrane
Stroma (inside of chloroplast)

5. Overall Equation 6CO2 + 6H2O + sunlight C6H12O6 + 6O2
6CO2 comes from us breathing out, from burning of fossil fuels, and from decaying organic matter
C6H12O6 is glucose, which makes up complex carbohydrates such as starch, which heterotrophs take in as food
6O2 comes from the splitting of water

6. What is the glucose used for?

7. Factors that affect rates of photosynthesis
Light intensity
Amount of water available
Amount of CO2 available

8. Section 8-3
Cellular Respiration

9. What is cellular respiration?
The process by which food molecules are broken down to produce ATP
Purpose: To obtain energy for life processes

10. What affects the rate of cellular respiration?
Number of mitochondria in a cell
Amount of carbohydrates available
Amount of oxygen available

11. Which organisms carry out cellular respiration?
Plants
Animals
Fungi
Etc. (every living cell)

12. Overall Equation for C.R.
C6H12O6 + 6O2  6CO2 + 6H2O + energy

13. Steps of Cellular Respiration
Glycolysis
Where? Cytoplasm of cell
What? Breakdown of glucose
What does it require? 2 ATPs to get started
What forms? 4 ATPs, 2 NADHs, 2 pyruvates (most of glucose’s energy is still stored in pyruvate)

14. What happens next?
If oxygen is present, pyruvate is transported to the mitochondrial matrix where it is converted to CO2 through the Krebs cycle
The Krebs cycle produces 6 CO2, 2 ATP, 8 NADH, 2 FADH2

15. What happens next?
The NADH & FADH2 from the Krebs cycle release electrons to the Electron Transport Chain (ETC) in the mitochondrial membrane & protons to the mitochondrial matrix, creating a concentration gradient. They diffuse through ATP synthase, creating 32 ATPs.

16. Electron Transport Chain
Oxygen is the final electron acceptor in the ETC.
Protons & electrons are transferred to the O2 to form water
The Krebs cycle and ETC are part of aerobic cellular respiration (oxygen present)

17. What if there’s no oxygen available?
Without oxygen, the proteins in the ETC can’t pass electrons so oxygen can’t accept the electrons and therefore ATP production stops.

18. Anaerobic environment
If oxygen is not present after glycolysis, fermentation occurs to produce small amounts of ATP to keep the cell from dying.

19. Fermentation Alcohol (a.k.a. Alcoholic) Lactic Acid
Produces CO2, ethyl alcohol, 2 ATP
Yeast cells do this (CO2 released makes bread rise) & some bacteria
Lactic Acid
Produces lactic acid & 2 ATP
Muscle cells do this during strenuous exercise, muscles get sore

20. Types of Cellular Respiration Summary
Aerobic
Requires oxygen
Produces 36 ATP—very efficient
Lots of energy!!!
Anaerobic
Does not require oxygen
Supplies energy when oxygen is scarce
Called fermentation
Produces 2 ATP—inefficient

21. Comparing Photosynthesis and Cellular Respiration
Food synthesized
Energy from sun stored in glucose
CO2 taken in
Oxygen given off
Produces sugar
Requires light
Occurs only in presence of chlorophyll
CELLULAR RESPIR.
Food broken down
Energy from glucose released
CO2 given off
Oxygen taken in
Produces CO2 & H2O
Does not require light
Occurs in all living cells