1. Chapter 4 Photosynthesis

2. Photosynthesis is the process by which certain organisms use light energy To make sugar and oxygen gas from carbon dioxide and water What does it need? (Input) What does it make? (Output) Light energy PHOTOSYNTHESIS 6 CO 2 6+ H2OH2O Carbon dioxideWater C 6 H 12 O 6 6+ O2O2 GlucoseOxygen gas

3. Trophic Roles Autotrophs  Producers of the biosphere: produce organic molecules from CO 2 & inorganic raw materials Heterotrophs  consumers

4. Learning Target 1. Describe Oxidation & Reduction reactions

5. REDOX Reactions LEO the Lion Says GER OIL RIG

6. REDOX Reactions Oxidation When a compound loses electrons Reduction When a compound gains electrons CO 2 + H 2 O + energy → C 6 H 12 O 6 + O 2 CO 2 is reduced to form glucose Water is oxidized to form O 2 OIL RIG

7. Photosynthesis is a redox process, as is cellular respiration In photosynthesis H 2 O is oxidized and CO 2 is reduced Figure 7.4A, B Reduction Oxidation 6 O 2 6 H 2 O Reduction Oxidation 6 O 2 6 CO 2  6 H 2 OC 6 H 12 O 6   6 CO 2 

8. Learning Check If H2O is losing electrons than it is being reduced/oxidized Co2 is being reduced/oxidized, which means it is gaining/losing electrons.

9. Photosynthesis Overview Light reactions Depend on light Occur in Thylakoid Membrane Light Independent (“Dark”) reactions Does NOT need light Occurs in the Stroma