Exam 3: Light-dependent Reactions Flashcards
Where do high energy electrons get donated to in photosystem II?
Pheophytin
Where do electrons get passed to after pheophytin?
PQ
What is the flow of the ETC between PSII and PSI?
PQ –> Cytochrome complex –> Plastocyanin
How do protons get pumped into the thylakoid?
They are pumped by using the energy released when electrons are transported down the ETC
What happens to potential energy as electrons move down the ETC?
Decreases
What wavelength of light does photosystem II absorb?
680
What wavelength of light does photosystem I absorb?
700
Which photosystem oxidizes water?
Photosystem II
What is oxygenic photosynthesis?
The splitting of water by PSII to replace its electrons and form oxygen
What is the formula for oxygenic photosynthesis?
2 H2O –> 4H+ + 4e- + O2
How many photons are absorbed by P680 and P700?
4 EACH
At PSI, where are electrons passed down to?
Ferredoxin
What transfers electrons to NADP+
NADP+ reductase, forms NADPH
Does NADPH have reducing or oxidizing power?
Reducing
What type of pattern describes how PSII and PSI interact?
Z scheme/noncyclic electron flow
How is ATP made?
Because there are lots of protons inside the thylakoid, ATP synthase produces ATP
How can you increase ATP production?
Cyclic electron flow: PSI can transfer electrons to PSII via ferredoxin to PQ instead of reducing NADP+ => increases ATP production
Why do cyclic and noncyclic electron flow coexist?
To produce additional ATP and meet the energy demand for manufacturing sugars from CO2
What is the ratio of ATP to NADPH produced in normal conditions?
Equal
What is the sequence for movement of electrons during light dependent reactions?
Water to P680 to P700 to NADP+
