Chapter 8 Photosynthesis

8-2 Photosynthesis: An Overview Timeline 1643 – Jan van Helmont Experiment: Only gave plants water then took careful measures of the plants growth. Conclusion: Plants gain most of their mass from water.

8-2 Photosynthesis: An Overview Timeline 1771 – Joseph Priestley Experiment: A candle would only burn when placed in a bell jar as long as a plant was also in the bell Jar Conclusion: Plants produce a substance needed to support burning (Oxygen).

8-2 Photosynthesis: An Overview Timeline 1779 – Jan Ingenhousz Experiment: Place aquatic plants in water, then exposed then to conditions of light and no light. Plants produced bubbles when light was present Conclusion: Aquatic plants will produce oxygen only when light is present.

8-2 Photosynthesis: An Overview Chemical Equation for Photosynthesis 6CO2 + 6H2O 6O2 + C6H12O6 Revised Formula 12H2O + 6CO2 6O2 + C6H12O6 + 6H2O Light Chlorophyll Light Chlorophyll

Photosynthesis

Photosynthesis: Reactants and Products Section 8-2 Light Energy Chloroplast CO2 + H2O Sugars + O2 Go to Section:

8-2 Photosynthesis: An Overview Light & Pigments Chlorophyll – Pigment in the Chloroplasts of plant cells that absorbs light energy. Pigment: a substance which absorbs light. 2 Types of Chlorophyll Chlorophyll a & Chlorophyll b Work together to absorb all but green light waves (green is reflected which makes plants appear green). Also contain Carotene – Pigment that reflects red, orange, and yellow (seen mostly in the Fall).

Figure 8-5 Chlorophyll Light Absorption Section 8-2 Absorption of Light by Chlorophyll a and Chlorophyll b Chlorophyll b Chlorophyll a V B G Y O R Go to Section: