1. Photosynthesis
Chapter 6

2. 6.1 Vocabulary Photosynthesis – Light-dependent reactions –
Calvin Cycle –
Light-Independent reactions –

3. Photosynthesis in nature
Autotrophs: biotic producers; make their own food photoautotrophs; chemoautotrophs
Heterotrophs: biotic consumers; obtain organic food by eating other organisms or their by-products (includes decomposers)

4. 6.1 An Overview of Photosynthesis
Show Photosynthesis Video

5. 6.1 Life is powered by sunshine.
Energy from the sun is captured by plants, algae, and certain bacteria using photosynthesis.
1% of all energy on earth is captured by photosynthesis, and provides all energy which drives everything.

6. The chloroplast Sites of photosynthesis Double membrane
Pigment: chlorophyll (located in the thylakoid)
Light dependent reactions occur in the thylakoid
Light independent reactions occur in the stroma

7. Pigments Chlorophyll pigments absorb blue and red but reflect green.
Carotenoid pigments absorb violet and blue but reflect yellow, orange, and red.

8. Why Photosynthesis?

9. Light Dependent/Independent Reactions

10. Photosynthesis: an overview
The light-dependent reactions convert light energy into chemical energy (ATP).
The molecules of ATP produced in the light-dependent reactions are then used to fuel the light-independent reactions that produce simple sugars.
6CO2 + 6H2O → C6H12O6 + 6O2

11. 6.1 Sum It All Up!
Photosynthesis uses energy from sunlight to power the synthesis of organic molecules from CO2 in the air. In plants, photosynthesis takes place in specialized compartments within chloroplasts.

12. 6.2 Vocab
Pigments –
Carotenoids -

13. 6.2 Sum It All Up!
Plants use pigments like chlorophyll to capture photos of blue and red light, reflecting photons of green wavelengths.
Why do the leaves on a tree change color in the fall?

14. Light Dependent Reactions Stage 1 & Stage 2
Located in the thylakoid membrane
Pigment molecules are struck by light and give off an electron
Excited e- is trapped by a primary e- acceptor and sent through the electron transport chain
Electron transport produces ATP
e- is replaced by splitting water (releases O2)
Produces ATP & NADPH

15. Light Independent Reactions Stage 3 (final stage)
Also called the Calvin Cycle
Occurs in the stroma of the chloroplast
3 molecules of CO2 are converted into glyceraldehyde 3-phosphate (G3P)
G3P can then be used by the plant to make glucose and other organic compounds

16. Calvin cycle

17. How Autotrophs Use Intermediates and Products of Photosynthesis
Sugar phosphates are used as cellular fuel and as building blocks in synthesis of carbohydrates
Sucrose is transported from leaves to all parts of the plant
Starch is the main storage form of carbohydrate in plants

18. A review of photosynthesis