Biology 3A

Photosynthesis Uses light energy to convert i__________ molecules to o__________ molecules Occurs in the c____________ of plant cells and some protists and the cytoplasm of cyanobacteria Occurs as a series of reactions, involving many different enzymes Involves light d__________ and light i_______________ reactions (the Light and Dark reactions) Net equation: ATP and ADP are used to transfer e__________ NADP is used as a hydrogen carrier

Photosynthesis Uses light energy to convert inorganic molecules to organic molecules Occurs in the chloroplasts of plant cells and some protists and the cytoplasm of cyanobacteria Occurs as a series of reactions, involving many different enzymes Involves light dependent and light independent reactions (the Light and Dark reactions) Net equation: carbon dioxide + water + solar energy  glucose + oxygen + water ATP and ADP are used to transfer energy NADP is used as a hydrogen carrier

Summary of reactions

Where it happens

Light reaction Occurs in the g________ (thylakoid membrane) of the c________________ Inputs are l_________ and w_____________ Light strikes photosystem II Electrons pass along until they reach the primary electron acceptor W______ is split into hy_________ ions and o________ atoms Electrons pass down the electron transport chain to photosystem I, forming ATP The three products of the light reaction are NADPH & ATP are then used in the C__________ Cycle

Light reaction Occurs in the grana (thylakoid membrane) of the chloroplast Inputs are light and water Light strikes photosystem II Electrons pass along until they reach the primary electron acceptor Water is split into hydrogen ions and oxygen atoms Electrons pass down the electron transport chain to photosystem I, forming ATP The three products of the light reaction are NADPH, ATP, and O 2 NADPH & ATP are then used in the Calvin Cycle

The Grana – photosystems I and II and the electron transport chain

ATP and ADP Act as chemical batteries Carry and release small amounts of energy energy adenosine phosphate adenosine ATP ADP

Carrier proteins Carry hydrogen ions to electron transport chains NADP  NADPH + H +

Light independent (Dark) reaction Occurs in s________ of the c____________ Inputs are _______ and ________ from the light reaction, and ____________________ First step is carbon fixation A series of reactions lead to the production of water, NADP+ and ADP, and sugar NADP+ and ADP return to the light reaction The carbon of the sugar product comes from _____________________________

Light independent (Dark) reaction Occurs in stroma of the chloroplast Inputs are NADPH and ATP from the light reaction, and CO 2 First step is carbon fixation A series of reactions lead to the production of water, NADP+ and ADP, and sugar NADP+ and ADP return to the light reaction The carbon of the sugar product comes from CO 2

Calvin cycle

Summary of photosynthesis Light dependent reaction Occurs in the Water is s Inputs are Outputs are Involves p________________ I and II and e____________ transport chain Light independent reaction Occurs in the Carbon is f Inputs are Outputs are Involves the C_________ cycle

Summary of photosynthesis Light dependent reaction Occurs in the grana Water is split into hydrogen ions and oxygen Inputs are light and water Outputs are ATP, hydrogen ions and oxygen Involves photosystems I and II and electron transport chain Light independent reaction Occurs in the stroma Carbon is fixed Inputs are ATP, hydrogen ions and carbon dioxide Outputs are glucose, water and ADP Involves the Calvin cycle

Factors affecting rate of photosynthesis Temperature Light Concentration of carbon dioxide Humidity

Factors affecting rate of photosynthesis Temperature as temperature increases, photosynthesis increases, until temperature gets too high  enzymes denature Light as light increases, photosynthesis increases, until maximum level reached Concentration of carbon dioxide as carbon dioxide increases, photosynthesis increases, until maximum level reached Humidity if humidity decreases, stomata will close to conserve water, hence reducing carbon dioxide, and slowing photosynthesis

Factors affecting rate of photosynthesis Carbon dioxide concentration Temperature Oxygen production Light Oxygen production Oxygen production Oxygen production Humidity

Factors affecting rate of photosynthesis Carbon dioxide concentration Temperature Oxygen production Light Oxygen production Oxygen production Oxygen production Humidity