1. Changing Colorful Leaves
and Photosynthesis

2. What do autumn leaves and ripening bananas have in common?

3. Photosynthesis Review Photosynthesis with the students:
What’s needed? Light, CO2, and water
What’s produced? Glucose, Sugars or carbohydrates, Oxygen

4. The Electromagnetic Spectrum
Light we can see!

5. Chlorophyll A and B
Absorbs energy from the sunlight to transform carbon dioxide and water into carbohydrates
Chlorophyll is what gives plants their green color
Two types of chlorophyll are found in the chloroplast of plants and green algae are chlorophyll a and b. Both chlorophylls absorb light most strongly in the red and violet parts of the spectrum. Green light is absorbed poorly. Thus when white light shines on chlorophyll-containing structures like leaves, green light is transmitted and reflected and the structures appear green.
Chlorophyll A- has a more green-blue color
Chlorophyll B-has a deep green color
The only difference between these two is a slight variation in the chemical composition and structure

6. Carotene and Xanthophyll
Yellow and orange accessory pigments found in plants
Carotenoids which also participate in photosynthesis
Present all year long
Chloroplasts also contain carotenoids. These are also pigments with colors ranging from red to yellow.
Carotenoids absorb light most strongly in the blue portion of the spectrum. They thus enable the chloroplast to trap are larger fraction of the radiant energy falling on it.
Carotenoids are often the major pigments in flowers and fruits. The red of a ripe tomato and the orange of a carrot are produced by their carotenoids.
In leaves, the carotenoids are usually masked by the chlorophylls. In the autumn, as the quantity of chlorophyll in the leaf declines, the carotenoids become visible and produce the yellows and reds of autumn foliage.

7. Seasons SUMMER Long hours of sunlight Good supply of liquid water
Plants are busy making carbohydrates
Plants storing food
Plants growing
WINTER
Days are shorter
Water is harder to come across
Annuals, Perennials, Evergreens

8. Perennials
Live for more than two years
trees and shrubs, and herbaceous plants with soft, fleshy stems.
Woody parts of trees and shrubs can survive the cold.
The above ground parts of herbaceous plants (leaves, stalks) will die off
Underground parts (roots, bulbs) will remain alive.
In the winter, plants rest and live off stored food until spring.
Annuals
complete their life cycle in one growing season.
Garden flowers, bulbs
Die when winter comes, but their seeds remain, ready to sprout again in the spring
Evergreens
keep most of their leaves during the winter
have special leaves, resistant to cold and moisture loss
Pine, fir trees, holly
may continue to photosynthesize during the winter as long as they get enough water

9. Summer to Fall
As the bright green fades away, we begin to see yellow and orange colors.
JUST LIKE AS THE CHLOROPHYLL DISSOLVES IN A GREEN BANANA TO REVEAL A YELLOW BANANA!
Small amounts of these colors have been in the leaves all along. We just can't see them in the summer, because they are covered up by the green chlorophyll

10. Colors of Fall Reds and Purples Brown
Maples, glucose is trapped in the leaves after photosynthesis stops.
Anthocyanins pigments
Sunlight and the cool nights of autumn cause the leaves turn this glucose into a red color.
Brown
- Oaks, due to wastes left in the leaves.