Photosynthesis

Question 1

Outline light dependant reaction

Answer 1

Electrons in PSII excited by light energy (to higher energy level)
These electrons travel down electron transport chain.
This releases energy used to actively pump H+ ions across the membrane into stroma
H+ ions travel down concentration gradient through ATP synthase which phosphorylates ADP and inorganic phosphate into ATP
The electrons excited further at PSI where it provides energy to combine NADP and H+ into reduced NAD
Oxygen is the final electron acceptor
(photolysis of water forms H+ and also replaces electrons which are excited in PSII)

Question 2

Outline cyclic phosphorylation

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Answer 2

Only PSII used 
No reduced NADP formed 
No oxygen formed
Electron excited and travels down ETC 
Then transported back to PSII 
Only small amounts of ATP made

Question 3

Outline Calvin cycle

light independant reaction

Answer 3

CO2 and RuBP combine, catalysed by RuBisCO
This forms 2xGP
GP is phosphorylated with 2xATP and reduced with 2x reduced NADP
Forms 2x TP
5/6 TP (most of it) is used to regenerate RuBP as it gets phosphorylated by 1x ATP
1/6 TP used to produce hexose sugars (sucrose)

Question 4

What does this produce
TP + TP =
TP + Fatty acids =

Answer 4

Hexose sugar
Glycerol

(Some amino acids made with GP)

Question 5

What effects photosynthesis?

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Answer 5

Temperature (ATP synthase denatures and proton pump and membrane more leaky)

Light intensity (effects photolysis)

Water stress (effects formation of electrons)

CO2 levels (CO2 needed in Calvin Cycle to be fixed on RuBP)