1. Photosynthesis
Chapter 8

2. Energy & Life

3. Energy The ability to do work. Can be stored in chemical bonds.
Cells need energy to do things like active transport, dividing, moving, and producing and storing proteins.
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4. Autotrophs vs. Heterotrophs
Organisms that make their own food.
AKA: producers
Ex: plants
Organisms that obtain energy from the food that they eat.
AKA: consumers or decomposers
Ex: sheep, wolves, mushrooms

5. ATP (adenosine triphosphate)
The main energy storage compound for living things.
ATP is NOT good to store lots of energy for a long time (glucose is used then).
Has three phosphate groups.

6. ADP (adenosine diphosphate)
Same as ATP, but with only two phosphate groups.
When a cell has extra energy, it stores it by adding a phosphate group to ADP, making ATP.
To release the energy, the bond is broken, converting ATP back to ADP.

7. Photosynthesis: An Overview

8. Light & Pigment
White light is actually a mixture of different wavelengths of light.
Pigments: light absorbing molecules that gather the sun’s energy.
The plant’s principle pigment is chlorophyll.
Energy absorbed by chlorophyll is transferred directly to electrons in the chlorophyll molecule. These high energy electrons make photosynthesis work.

9. So why are leaves green?
Look at the wavelengths of light that chlorophyll absorbs & uses in photosynthesis
The colors that are left are reflected back and that is what you see.

10. Electron Carriers
NADP+: can accept 2 high-energy electrons by bonding with an H+; an “uncharged” energy carrier
Similar to ADP
NADPH: the “charged” version
Similar to ATP

11. 6H2O + 6CO2 ----------> C6H12O6+ 6O2
Photosynthesis: An Overview ● The process that captures light energy and uses it to make carbohydrates (glucose).
sunlight
6H2O + 6CO > C6H12O6+ 6O2
Water: Comes in through the roots
Carbon Dioxide: Comes in from the air
Glucose: Stored as chemical energy
Oxygen: leaves back to the air

12. Factors Affecting Photosynthesis
Temperature
Best between 0 & 35˚C
Light intensity
A higher intensity increases the rate of photosynthesis until a maximum rate is reached.
Water
A shortage can stop photosynthesis.

13. The Process of Photosynthesis

14. Where does it take Place?
In the chloroplasts.

15. Photosynthesis 2 Parts: Light dependent reactions
Light independent reactions (AKA dark reactions or the Calvin Cycle)

16. Light Dependent Reactions
Where? The granum
1.) chlorophyll absorbs light
2.) H2O is split; O2 is released
3.) ATP & energy carriers (NADPH) are formed & take the energy (stored in their bonds) to the light independent reaction

17. Light Independent Reactions/ The Calvin Cycle
Where? The stroma
1.) ATP & NADPH are broken down (ADP & NADP+) are recycled back to the light dependent reaction
2.) the energy released is used to convert CO2 to C6H12O6

18. Cellular Respiration & Fermentation
Chapter 9

19. Cellular Respiration: An Overview

20. calorie The amount of energy needed to raise 1g of H2O 1○ C.
When burned, 1g of glucose releases 3811 calories of heat energy.
Food labels show Calories (= calories).

21. Two more Electron Carriers
NAD+ & FAD: “uncharged” energy carriers
Similar to ADP
NADH & FADH2: the “charged” versions
Similar to ATP

22. C6H12O6 + 6O2 ----------> 6H2O + 6CO2
Cellular Respiration
Releases energy (ATP) by breaking down food in the presence of oxygen.
C6H12O6 + 6O > 6H2O + 6CO2
Oxygen: taken in from the air
Water: released as waste
Carbon Dioxide: released into the air
Glucose: Plants- have it stored from photosynthesis; Animals- get it from food

23. The Process of Cellular Respiration

24. Cellular Respiration Three parts: Glycolysis Kreb’s cycle
Electron Transport Chain

25. Glycolysis Where? The cytoplasm
1.) C6H12O6 is split to form 2 pyruvic acids (2C3H6O3)
2.) the energy is captured in ATP & energy carriers (NADH)

26. Kreb’s Cycle Where? The mitochondria
1.) 2 pyruvic acids (2C3H6O3) are broken down into CO2
2.) the energy is captured in ATP & energy carriers (NADH& FADH2)

27. Electron Transport Chain
Where? The mitochondria
1.) Energy carriers (NADH & FADH2) are broken apart; the energy released is used to make ATP
2.) O2 bonds with leftover H+ to make H2O

28. Fermentation

29. Aerobic vs. Anaerobic
When O2 is present & all of cellular respiration occurs, 36 ATPs are made from 1 C6H12O6.
Aerobic: reactions that require oxygen (the Kreb’s cycle & electron transport chain)
When there is no O2, only glycolysis occurs & 2 ATPs are made from 1 C6H12O6.
Anaerobic: reactions that do not need oxygen (glycolysis)

30. Glycolysis Advantage: ATP can be made without oxygen
Disadvantage: the cell will run out of NAD+ & glycolysis will stop
So…
Fermentation occurs!

31. Fermentation
Allows glycolysis to continue by converting NADH into NAD+
Anaerobic
Two types:
Alcoholic fermentation
Pyruvic acid + NADH -> alcohol + CO2 + NAD+
Lactic Acid fermentation
Pyruvic acid + NADH -> lactic acid + NAD+