1. Chapter 8: Photosynthesis

2. Autotrophs
Plants and some other types of organisms are able to use light energy from the sun to produce food.
Contain chlorophyll, a pigment that captures sunlight.

3. Heterotrophs Organisms that cannot make their own food.
Cannot use sun’s energy directly.

4. Candles release energy as HEAT & LIGHT
Comes in many forms including light, heat, and electricity.
Can be changed from one form to another.
Can be stored in chemical compounds.
Candles release energy as HEAT & LIGHT

5. ATP – Cellular energy Adenosine triphosphate
Contains two, high-energy phosphate bonds
Also contains the nitrogen base adenine & a ribose sugar
Energy is stored in the bond between the 2nd and 3rd phosphates.
ENERGY

6. ADP Adenosine Diphosphate
ATP releases energy, a free phosphate, & ADP when cells take energy from ATP

7. Using energy in atp ATP only provides energy for a few seconds.
It is constantly being used and remade by cells.
Provides energy for all cell’s activities:
Active Transport
Movement
Photosynthesis
Protein Synthesis
Cellular Respiration
Many more!

8. Storing and releasing energy
Adding A Phosphate Group To ADP stores Energy in ATP
Removing A Phosphate Group From ATP Releases Energy & forms ADP
Loose
Gain

9. glucose Glucose is a monosaccharide C6H12O6
One Molecule of glucose Stores 90 Times More Chemical Energy Than One Molecule of ATP

10. Photosynthesis
In words: Involves the use Of light energy to convert Water (H20) and Carbon Dioxide (CO2) into Oxygen (O2) and High Energy Carbohydrates (sugars, e.g. Glucose) & Starches.

11. The photosynthesis equation
6CO H2O + energy  C6H12O6 + 6O2
Carbon Dioxide + Water + Sunlight  Glucose + Oxygen

12. The photosynthesis equation

13. pigments
In addition to water, carbon dioxide, and light energy, photosynthesis requires Pigments
Chlorophyll is the primary light-absorbing pigment in autotrophs
Chlorophyll is found inside chloroplasts

14. Photon = Light Energy Unit
Light and pigments
Energy From The Sun Enters Earth’s Biosphere As Photons
Photon = Light Energy Unit
Light Contains A Mixture Of Wavelengths
Different Wavelengths Have Different Colors

15. Light and Pigments
Different pigments absorb different wavelengths of light
Photons of light “excite” electrons in the plant’s pigments
Excited electrons carry the absorbed energy
The main pigments found in plants is chlorophyll.
Chlorophyll is found in chloroplasts.

16. chlorophyll
Chlorophyll absorbs light well in the blue-violet and red regions of the visible spectrum.

17. Inside a chloroplast
Contain saclike photosynthetic membranes called thylakoids.
Thylakoids are arranged in stacks called grana (singular: granum).
Contain clusters of chlorophyll and other pigments as well as proteins known as photosystems that capture sunlight energy.
Single
thylakoid

18. Inside a chloroplast
Gel-like material surrounding the grana = stroma.

19. Electron carriers
When electrons in chlorophyll absorb sunlight, the electrons gain A LOT of energy.
Chloroplasts use electron carriers to transfer these electrons from chlorophyll to other molecules.

20. NADP+ One electron carrier is NADP+.
It accepts and holds 2 high-energy electrons along with a hydrogen ion (H+).

21. Light-dependent reactions
Part 1 of Photosynthesis
Occurs across thylakoid membranes.
Uses light energy.
Produce oxygen from water.
Convert ADP to ATP and NADP+ to NADPH.

22. Light-dependent reactions

24. Light-dependent reactions summary
Reactants
Water (H2O)
Sunlight energy
Products
ATP
NADPH

25. The calvin cycle Also known as: Light-Independent Reactions
Occur in stroma
Uses ATP and NADPH from the Light-Dependent Reactions to form high-energy sugars.

26. The calvin cycle Six CO2 molecules enter the cycle.
Bonds in the ATP and NADPH molecules are broken to release the stored energy.
This energy is used to turn the CO2 molecules into a 6-carbon sugar (glucose).

27. Calvin cycle summary Reactants Products CO2 ATP NADPH
C6H12O6 (high-energy sugar)
ADP
NADP+

28. Photosynthesis summary
Light-Dependent Reactions
Reactants
Products
H2O
Sunlight
ATP + O2
NADPH
Calvin Cycle/Light-Independent Reactions
Reactants
Products
CO2 (from environment)
ATP
NADPH
C6H12O6
ADP
NADP+

29. Photosynthesis summary

30. Factors affecting rate of photosynthesis
Temperature
Amount of Water
Light availability