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Cellular Processes Photosynthesis

What is Photosynthesis? process whereby light energy from the sun is converted to chemical energy stored in the bonds of sugar (glucose) occurs in the chloroplasts of plants, algae, and some bacteria

Overall Equation for Photosynthesis

Understanding Chemical Equations Reactants are on the left side of the equation Products on the right side of the equation Reactants  Products Reactants yield Products A + B  C + D

Photosynthesis Carried out in two phases: Light-Dependent Reaction Requires light energy Light-Independent Reaction Does not require light energy Also known as Calvin Cycle

Overview of Photosynthesis

PHASE 1: LIGHT-DEPENDENT REACTION Thylakoid Occurs in the thylakoids within the chloroplast

PHASE 1: LIGHT-DEPENDENT REACTION Light splits the water molecule at the thylakoids H2O is broken down into Hydrogen ions, an electron, and Oxygen atom Oxygen is released to the atmosphere Hydrogen is kept to make NADPH, an energy storage molecule Electrons are passed into the next step, the electron transport chain

PHASE 1: LIGHT-DEPENDENT REACTION Electron Transport Chain (ETC) made of proteins that accept and transfer the electrons electrons pass from protein to protein along the ETC

PHASE 1: LIGHT-DEPENDENT REACTION Formation of NADPH and ATP Electrons at the end of the “chain” are used to make NADPH from NADP+ NADP+ + 2e- + H+  NADPH NADPH is an energy carrier molecule that takes energy to the stroma for the Calvin Cycle Phosphate is added to ADP to form ATP and is carried to the Calvin Cycle

Energy Currency = ATP Chemical Energy and ATP Energy can be stored in many forms: Light Heat Electricity Chemical Bonds!

Energy Currency = ATP (Video) Bonds = Energy

Energy Currency = ATP Energy in ATP is released when it is converted to ADP The characteristics of ATP make it an exceptionally useful molecule that is used by all types of cells as their basic energy source

PHASE 2: LIGHT-INDEPENDENT REACTION Occurs in the stroma, the colorless fluid that fills the chloroplast Stroma

PHASE 2: LIGHT-INDEPENDENT REACTION NADPH and ATP lose their stored energy and hydrogen is fixed to CO2 to build glucose six molecules of carbon dioxide enter the Calvin Cycle and eventually produce one molecule of glucose (C6H12O6) 6 molecules of Carbon Dioxide 1 molecule glucose

Overview of Photosynthesis

SUMMARIZE: 3-2-1 Tell me 3 steps of the light-dependent reaction 2 phases in photosynthesis 1 main goal of photosynthesis