Photosynthesis Unit 3 Lecture 8 Photosynthesis Photosynthesis the

Photosynthesis Unit 3 – Lecture 8

Photosynthesis �Photosynthesis: the process used by autotrophs which changes solar energy, water [H 2 O], and carbon dioxide [CO 2] into glucose [C 6 H 12 O 6] and oxygen [O 2] Equation for Photosynthesis: � E + H 2 O +CO 2 C 6 H 12 O 6 + O 2

Photosynthesis – cont’d �takes place in the chloroplasts of the cell �“chloro” – green [pale green] �contain green pigment, chlorophyll � “phyll / phyllos” = leaf � chloroplasts are FILLED with chloro. PHYLL

Light Dependent Reactions sunlight transfers a photon of solar energy to chlorophyll in the chloroplast which exites an electron e- gets knocked out of placement

Light Dependent Rxns – cont’d e- travels down the Electron Transport Chain [also called Electron Transport System] as e- travels, it loses E that E splits H 2 O [called photolysis] into Oxygen [O 2] Gas which is released into the atmosphere and Hydrogen [H +] Ions

Light Dependent Rxns – cont’d … Hydrogen [H+] Ions… which either bonds with NADP+ is pumped into the thylakoid to form NADPH which goes to the light independent reactions to form a gradient of charge AND concentration [called electrochemical gradient]

Light Dependent Rxns – cont’d …Electro. Chemical Gradient… which causes the H+ ions to funnel through the ATP Synthase to form a small amount of ATP

Light Dependent Rxns – cont’d …to form a small amount of ATP… which goes on to the Light Independent Reactions

Summing it up… Equation: � E + H 2 O +CO 2 C 6 H 12 O 6 + O 2 �of the things in our equation…which things are input or formed in the light dependent reactions of photosynthesis? �input: energy + water �formed: oxygen gas

ATP Synthase �Hydrogen Ions are pumped into the thylakoid membrane after water is split… �ions form electrochemical gradient �ions funnel through ATP synthase � turns “crank” �energy from turning makes ADP+P into ATP

Light Independent Reactions �aka Dark Reactions or Calvin Cycle �can occur in the LIGHT or the dark �[light rxns can only occur when there is sunlight]

The Calvin Cycle

Light Indep. Rxns – cont’d �What you NEED to know: �can occur with or without light present �composed of the calvin cycle �Carbon dioxide (CO 2) is taken in and combined with the H+ from NADPH (using ATP) to make Glucose (C 6 H 12 O 6). �leftovers – ADP and NADP+ go back to light dependent reactions

Summing it up… Equation: � E + H 2 O +CO 2 C 6 H 12 O 6 + O 2 �of the things in our equation…which things are input or formed in the light INdependent reactions of photosynthesis? �input: carbon dioxide [and some water] �formed: glucose

Overview - Photosynthesis solar energy [photon] O 2 CO 2 ATP a little bit of H 2 O NADPH thylakoids ADP H 2 O stroma NADP+ C 6 H 12 O 6

IMPORTANT!! �Be sure to know: �what goes in � where that came from �what goes out � where that’s going