1. An overview of photosynthesis
Section 8.2

2. Light Visible spectrum of light ranges from red to violet
Our eyes are able to process these wavelengths and produce colours
We see reflected colours

3. Pigments
Photosynthetic organisms capture energy from the sunlight with pigments
Chlorophyll absorbs light in red and blue part of spectrum
Green part is reflected
Why leaves appear green

4. Why do leaves turn brown in fall?
Chlorophyll breaks down before carotenoids
These orange and red accessory pigments are then exposed for everyone to see

5. Chloroplasts
Contain sac like photosynthetic membranes called thylakoids
Interconnected and arranged as grana
Chlorophyll is located in thylakoid membranes
Stroma – fluid filled portion of chloroplast

6. How do Chloroplasts work?
Chlorophyll absorbs light energy very well
This energy is transferred to electrons in the chlorophyll molecule
This makes a large supply of high energy electrons
Driving force for photosynthesis

7. Why are the high energy electrons important?
In a chemical sense, these electrons are highly reactive – they act as fuel
A carried is needed to take them where it is needed to go
This carrier, or taxi, is NADP+ and a H+ ion
Nicotinamide adenine dinucleotide phosphate
Conversion of NADP+ and H+ to NADPH stores some of the suns light energy
Acts as a starting point for chemical energy formation

8. Overview of Photosynthesis
Photosynthesis uses the suns energy to convert water and carbon dioxide into high energy sugars and products

9. Light dependent and Light independent reactions
Light dependent reactions use energy from the sun
Water needed, converted into H+ ions and source of electrons
Oxygen is a by – product
NADPH and ATP generated
Reactions occur in thylakoid membrane

10. Light independent reactions
Glucose is produced via the Calvin Cycle
ATP and NADPH are used to produced high energy sugars from carbon dioxide
Light independent reactions rely on the products of the light dependent reactions!

11. Writing assignment
Write a paragraph explaining why plants require light. Describe how light is used to produce energy in a form that cells can use.