Photosynthesis The process of producing the organic molecule Needed for cellular respiration.

What is Photosynthesis? Photosynthesis = “Light Making” Autotrophs: Organisms that make their own food (glucose) Occurs in the chloroplasts of plant cells Chlorophyll: Pigment in plant cells that absorbs the sunlight needed for photosynthesis.

H2O + CO2 + Sunlight  C6H12O6 + O2 Chemical Equation: H2O + CO2 + Sunlight  C6H12O6 + O2 Water Carbon Dioxide Energy Glucose Oxygen Reactants Products

Step 1: The Light Reactions An enzyme splits apart water to make electrons and oxygen. Oxygen is a waste product. Energy from the sun moves the electrons through an Electron Transport Chain. ATP is made to use in Step 2. Occurs inside the chloroplast

Step 2: The Dark Reactions The Calvin Cycle A series of chemical reactions occur that turn carbon dioxide into glucose.

The Big Picture:

Summary: Light Reactions (Electron Transport Chain): Powered by Sunlight H2O split to make O2 Dark Reactions (Calvin Cycle): CO2 converted into C6H12O6

Factors that Effect Photosynthesis:

Gas Exchange Guard Cells: Specialized cells in plant leaves that open and close to: Let CO2 into the plant Let O2 and water out of the plant Stomata: The opening of the guard cell

Sunlight & Pigments Sunlight may be called: Light travels in waves. Insolation: Incoming Solar Radiation Light travels in waves. Pigments absorb these waves. Chlorophyll: Main pigment that absorbs all waves but green Accessory Pigments: “Helping Pigments” that absorb additional light waves

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