Lesson 8: Light-Dependent Reactions

chlorophyll

• catalyzes the making of glucose

• absorbs light energy

balanced photosynthesis equation

6CO2 + 6H20 + light = C6H12O6 + 6O2

2 types of light reactions

• light-dependent

• light-independent

light-dependent reactions

• uses light energy to make ATP and NADPH

light-independent reactions

• uses ATP and NADPH to make glucose/other sugars

photosystem

• a protein complex made up of pigments that absorb light energy

the antenna complex

• takes in all the pigment and brings it to the reaction center

this diagram is the…..

antenna system

the 2 photosytems

1. photosystem I

2. photosystem II

reaction center for photosystem I

P700

reaction center for photosystem II

P680

b6-f complex

• uses excited electron energy to pump hydrogen from the stroma into the thylakoid space

NADP reductase

• an enzyme used to reduce NADP+ to make NADPH

final electron acceptor in photosynthesis

• NADPH

two products from pho

photophosphorylation

• the use of light energy from photosynthesis to make ATP from ADP

products from light-dependent reaction

• NADPH and ATP

cyclic photophosphorylation use

• when more ATP is needed

difference between cyclic and noncyclic photophosphorylation

1. in cyclic photophosphorylation only ATP is made but in noncyclic photophosphorylation NAPDH and ATP is made

2. cyclic photophosphorylation does not take the electron to reduce NADP+. Non cyclic photophosphorylation uses electron to reduce NADP+

the source of oxygen in light-dependent reactions

• the oxygen that is made in photosynthesis comes from H2O not CO2

say the steps of light dependent reaction out loud!

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say the steps of cyclic photophosphorylation out loud

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