Photosynthesis Essential Standard Bio.4.2.1 Analyze photosynthesis and cellular respiration in terms of how energy is stored, released, and transferred within the and between these systems.

Photosynthesis Photosynthesis – process by which plants capture energy in light and store it in organic compounds 2 steps: Light (dependent) reactions produce chemical energy Dark (Light independent) reactions synthesize sugar

1. Light (Dependent)Reactions Pigments absorb and reflect different colors of light Visible Light Spectrum – array of colors from splitting a beam of white light Chlorophyll reflects green light Plants appear green Carotenoids are accessory pigments that reflect orange, red, and yellow lights Autumn Colors!

1. Light (Dependent) Reactions Light reactions – initial phase of photosynthesis where light energy is transferred into chemical energy. Chlorophyll Process: Sun  Series of Pigments  ATP Synthesis Photosystem = cluster of pigment molecules that absorb light energy

2. Dark Reactions (Calvin Cycle) Dark reactions are known as light independent reactions Calvin Cycle – series of biochemical reactions that produces organic molecules using energy stored in ATP and NADPH Carbon Fixation  Reduction  Regeneration (sugar) Carbon Fixation – incorporate CO2 into organic compounds (sugar) Reduction – incorporating ATP and NADPH to reduce organic compounds Regeneration – incorporate ATP to “fix” carbohydrates

Photosynthesis Equation Equation for both light dependent and light independent cycles CO2 + H2O + light energy  Sugar (C6H12O6) + O2

Factors that Affect Photosynthesis Sunlight Carbon dioxide Water Temperature pH