1. Cellular Energy

2. Cellular Energy
Every organism must be able to obtain energy from its environment
Autotrophs: make food from sunlight
Examples?
Heterotrophs: get food from elsewhere
(Which are you?)

3. ATP (Adenosine Triphosphate)
Energy molecule used by cells
Composed of:
Nitrogen Base (Adenosine)
Sugar (Ribose)
3 phosphate groups

4. Forming and Breaking ATP
Energy is RELEASED when a phosphate group(P) is REMOVED/BROKEN
Energy is stored in the bond between the 2nd and 3rd phosphate group. When P is ADDED back, energy is ADDED/STORED
ATP  ADP + P + Energy
ADP: adenosine diphosphate
The P can be reused!

5. Photosynthesis Photo: light Synthesis: to put together
Process that uses the sun’s energy to make simple sugars (glucose)
All energy originates with the sun

6. Photosynthesis Equation
(Do you know it?)
What do plants need?
What do plants produce or give off?

7. Photosynthesis Reaction
6CO H2O  C6H12O O2
Carbon Dioxide + Water  Sugar + Oxygen Gas
Autotrophs carry out
photosynthesis!

8. Chloroplast
Organelle where photosynthesis occurs

9. Chloroplast Thylakoids: Storage sacs of chlorophyll
Grana: Stack of thylakoids
Stroma: Area outside the thylakoids

10. Trapping Light Thylakoid membrane traps the light using pigments:
Molecules that absorb specific light wavelengths
Chlorophyll absorbs most wavelengths of light except for green
Makes plants look green!
(Other plant pigments:
Xanthophyll: yellow
Carotene: orange)

11. Photosynthesis Processes
2 phases
Light-dependent reactions
Convert light energy into chemical energy
ATP produced is used to fuel the light-independent reactions
Light-independent reactions
Produces simple sugars
So, photosynthesis

12. Light Reactions (light-dependent reactions)
Requires Sunlight, Chlorophyll (to gather the suns energy) and Water
Happens in the thylakoid membrane of the chloroplasts.
Sunlight and water goes in
Oxygen, ATP and NADPH comes out
ATP: Cellular Energy
NADPH: Energy needed in the Light Independent Reactions to remove a P group from ATP.

13. Calvin Cycle (light-independent reactions)
Does not require sunlight
Occurs in the stroma of the chloroplast
CO2, ATP and NADPH goes in
Glucose (C6H12O6), ADP + P, and NADP+ comes out
NADP+ Energy needed in the light reactions to bond a P+ group to ADP
(Used to be called dark reactions, but that is misleading.)

15. Photosynthesis Requirements
Where does the plant get…
sunlight?
water?
carbon dioxide (CO2)?

16. Stomata

17. Products of Photosynthesis
Light Independent
Light Dependent
Sugar (glucose)
ADP + P
Oxygen (O2)
ATP

19. Cellular Respiration C6H12O6 + 6O2 --> 6CO2 + 6H2O + energy
Occurs in ALL living organisms
Process in which mitochondria break down sugar to produce ATP
C6H12O6 + 6O2 --> 6CO2 + 6H2O + energy
Photosynthesis reversed!

20. Stages of Respiration (with O2)
Glycolysis: in cytoplasm
This step is anaerobic (no oxygen needed)
Citric Acid Cycle (Kreb’s Cycle): in mitochondria
Electron Transport Chain: inner membrane of mitochondria

21. Mitochondria

22. Glycolysis Needs 2 ATP to start Produces 4 ATP
Breaks glucose into ATP and pyruvate

23. Citric Acid Cycle (Kreb's Cycle)
Produces 2 ATP and CO2
Breaks down a molecule of pyruvate

24. Electron Transport Chain
Produces 32 ATP (sometimes 34)
Occurs in the inner membrane of the mitochondria (cristae)
Energized electrons release energy as they pass from one protein to another

25. Cellular respiration makes a total of:
36-38 ATP

26. Fermentation
If oxygen is not present ATP can still be made in small amounts using this anaerobic process.

27. Fermentation Types Many foods are made this way.
2 Types of fermentation
Lactic Acid
Alcoholic

28. Lactic Acid Fermentation
Produces lactic acid and only 2 ATP
Occurs when the body is under stress and not getting enough oxygen

29. Alcoholic Fermentation
Used by yeast cells and some bacteria to produce:
CO2
Ethyl alcohol
This process is used to make bread and wine

31. Summary Photosynthesis Cellular Respiration Food synthesized
Food broken down
Energy from sun stored as glucose
Energy of glucose released
Carbon Dioxide taken in
Carbon dioxide given off
Oxygen given off
Oxygen taken in
Produces sugar
Produces CO2 & H2O
Requires light
Does not require light
Occurs only in the Chloroplast
Occurs in all living cells

32. The cycle of energy