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

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!

Light (Dependent) Reactions Light reactions – initial phase of photosynthesis where light energy is transferred into chemical energy. Chlorophyll Water enters and oxygen leaves the light reactions ATP and NADPH leaves to light reactions and goes to the Calvin cycle Photosystem = cluster of pigment molecules that absorb light energy

Calvin Cycle Also known as light independent reactions Calvin Cycle – series of biochemical reactions that produces organic molecules using energy stored in ATP and NADPH Carbon dioxide is used to make sugar ADP and P go back to the light reaction NADP goes back to the light reaction to get more H 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 Oxygen