1. Ch. 4.2 Photosynthesis

2. I. The Nature of Light A. The Sun is the source of energy on Earth. 1. The light you see is white light. 2. Light passing through a prism appears: red, orange, yellow, green, blue and violet as the visible spectrum.

3. B. When Light Strikes Objects 1. Transmission is when transparent materials allow light to pass through. 2. When light hits a shiny surface and light bounces back it’s called reflection. 3. Absorption is when dark objects take in light. 4. Most objects reflect some colors of the visible light spectrum while they absorb other colors.

4. Visible Light Spectrum

5. C. Plants and Light 1. Plants absorb some colors of the visible spectrum and reflect others. 2. When light strikes the green leaves of a plant, most of the green part of the spectrum is reflected. 3. Most of the other colors are absorbed.

6. Reflect, Absorb, Transmit

7. D. Plant Pigments 1. When light strikes a leaf, it is absorbed by the pigments found in the leaf’s cells. 2. Chlorophyll is the most abundant pigment in leaves. 3. Chlorophyll absorbs blue and red light and reflects green light. 4. Accessory pigments are also found in plants include orange and yellow pigments. 5. Most accessory pigments are hidden by the chlorophyll.

8. Plant Pigments

9. II. The Photosynthesis Process A. Part 1 of Photosynthesis the Plant captures Energy from the Sun. B. Part 2 of Photosynthesis the Plant uses that energy to produce food.

10. C. Capturing Energy 1. A substance that absorbs light absorbs energy. 2. Photosynthesis begins when light strikes the chlorophyll in a plant’s chloroplasts. This light energy powers the next stage.

11. D. The Chemistry of Photosynthesis 1. Plants use Carbon dioxide gas and Water as raw materials for photosynthesis. 2. During this stage of photosynthesis, Plants use the energy absorbed by chlorophyll to power a series of complex chemical reactions. 3. Plants produce Sugar and Oxygen gas.

12. E. The Photosynthesis Equation Carbon Dioxide + Water ---  Sugar + Oxygen CO 2 H 2 O C 6 H 12 O 6 O 2