1. 9.1 Energy in Living Systems
I. Chemical Energy
A. Almost all the energy in organic compounds comes from the sun
B. Photosynthesis
1. creates organic compounds from CO2 & H2O
2. Used by plants, algae, & prokaryotes
C. Autotrophs
1. make their own food so long as sunlight is available

2. 2. Organisms that cannot make their own food must eat autotrophs
II. Metabolism and the Carbon Cycle
A. Metabolism involves using energy to build organic molecules
B. The carbon cycle makes carbon compounds continuously available in an ecosystem
C. Photosynthesis
1. Takes place in chloroplasts
2. Converts CO2 & sunlight into glucose

4. ATP- Adenosine Tri Phosphate
ATP is energy the cell can use to do work
Like currency/money, only ATP is the right type of energy the cell can use
You can’t buy anything at the mall with the wrong money like Japanese Yen!
Energy is stored in the phosphate bonds
Energy is released when the phosphate bonds are broken

5. 9.2 Photosynthesis I. Harvesting Light Energy A. Chloroplasts
1. Organelles that convert light energy into chemical energy
2. Has two membranes (outer & inner)
a. both allow light to pass through
3. Inner membrane contains thylakoids

6. B. Electromagnetic Radiation
1. Forms = visible light, x-rays, radio, & microwaves
2. All have different wavelengths
a. the space between peaks
C. Pigments
1. Substance that absorbs certain colors & reflects all of the others
2. Chlorophyll is a green pigment in chloroplasts that absorbs light energy
a. absorbs mostly blue & red light, reflects green & yellow.

7. a. contain molecules that absorb light & are arranged in stacks
3. Two types of chlorophyll (a & b)
4. Pigments called carotenoids
a. absorb blue & green, reflect yellow, orange, & red light
b. when chlorophyll fades in the fall the carotenoids are exposed
D. Two Electron Transport Chains
1. During photosynthesis, one transport chain provides energy to make ATP, while the other provides energy to make NADPH

8. E. Producing Sugar
1. ATP & NADPH are used to produce energy storing sugar molecules from the carbon in carbon dioxide
2. Calvin Cycle – the most common method of carbon dioxide fixation
F. Factors that Affect Photosynthesis
1. light intensity, CO2 concentration, & temperature

9. 9.3 Cellular Respiration Where do we get our energy from?
After we eat, what has to happen to get energy from that food?
Energy is stored in the proteins, carbs and fats of food we eat, but we must release that energy and transfer into ATP.
This process begins with glycolysis.

11. I. Glycolysis
A. Def – enzymes break down one 6-carbon molecule of glucose into two 3-carbon pyruvate molecules
B. Glucose is the primary fuel for respiration
1. Formed when carbs like starch are broken down
2. When no carbs are available cells use fats
a. 1 gram of fat releases more energy than 2 grams of carbs

12. C. Steps of Glycolysis
1. Breaking down glucose
2. NADPH production
3. Pyruvate production

13. D. Glycolysis is an anaerobic process
1. takes place without oxygen
E. Aerobic process
1. metabolic process that takes place with oxygen

14. II. Aerobic Respiration
A. Humans can use oxygen to produce ATP
B. Krebs cycle
1. a series of reactions that produce electron carriers.
C. Up to 34 ATP molecules can be produced from one glucose molecule
III. Fermentation
A. the process in which carbohydrates are broken down in the absence of oxygen

15. B. Lactic Acid Fermentation
1. Can occur in humans & some animals during vigorous exercise when the muscles must operate without oxygen
C. Alcoholic Fermentation
1. an enzyme removes carbon from the carbon pyruvate