1. 1 Review Why are pigments such as chlorophyll needed for photosynthesis Predict How well would a plant grow under a pure yellow light- Explain 2 Review What is the function of NADPH Infer How would photosynthesis be affected if there were a shortage of NADP+ in the cells of plants. 3 Visual Thinking Draw two leaves- one green and one orange. Show which colors of visible light are absorbed and which are reflected by each leaf.

2. 8.2 Photosynthesis: An Overview
Ch 8 Photosynthesis
8.2 Photosynthesis: An Overview

3. Light Energy from the sun travels to Earth in the form of light
Sunlight is a mixture of different wavelengths
Some are visible to us some are not.

4. Pigments
Light absorbing molecules that gather the sun’s energy
Chlorophyll
Plants primary pigment.

5. Chlorophyll
Two types
Chlorophyll a and chlorophyll b
Absorb blue-violet and red regions of the spectrum
They appear green.

6. Carotene Red orange pigment
Secondary pigment, chlorophyll hides it most of the year
Chlorophyll breaks down earlier in the fall which gives leaves the fall colors.

7. Chloroplasts Organelle where photosynthesis occurs Thylakoids Grana
Saclike photosynthetic membranes in chloroplasts
Grana
Interconnected
stacks of thylakoids
Stroma
Fluid portion outside of the thylakoids.

8. Energy Collection
Chlorophyll absorbs light and is transferred to electrons.

9. High-Energy Electrons
Are highly reactive and require a special “carrier”
Carriers include:
NADP+
Accepts and holds two high-energy electrons, along with a hydrogen ion (H+)
Turns into NADPH which carries the electrons.

10. Photosynthesis Steps
“Plant” absorbs light energy and takes in CO2 and H2O
“Plant” releases O2 and makes sugar (glucose C6H12O6).

11. Photosynthesis involves two sets of reactions
Light-dependent reactions
Light-independent reactions.

12. Light-Dependent Reactions
Use energy from sunlight to produce ATP and NADPH
Occurs in Thylakoid
Requires water and releases oxygen.

13. Light-Independent Reactions
ATP and NADPH molecules produce high-energy sugars from carbon dioxide
Light is not needed
Occurs OUTSIDE of thylakoid but IN stroma.