Biology
Photosynthesis Need-to-Know
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Photosynthesis- the process whereby plants use the energy of sunlight to convert water and
carbon dioxide into oxygen and high-energy carbohydrates (glucose)
o Energy- the ability to do work
 Forms: light, heat, electricity, or sound
o Autotroph : organisms that make their own food by using light energy from sun
 Ex: green plants
o Heterotroph: obtain energy from the food they eat
 Ex: animals
o Chemical Equation:
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o
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CO2 taken in through stomata (openings) on the surface of leaf
Absorption of Sunlight
 Pigments
 Chlorophyll- green pigment in plants that absorbs light energy from sun
o Absorbs red and blue wavelengths, but reflects green
Chloroplast
 Structure – diagram
Light Reactions
 Location: thylakoid membranes
 Require light
Dark Reactions
 Other names: Calvin Cycle, Light Independent
 Location: stroma
 Do not require light
 Use the products of the light reactions
Energy Storing Compounds
 Used to trap high energy electrons into chemical bonds
 ATP- (Adenosine Triphosphate)- the energy currency of the cell
 Molecule that provides energy for cellular reactions and processes
 Energy is released when bond is broken to release a phosphate group
 Energy stored in these molecules is needed to make glucose(C6H12O6)
that the cell uses