Question

Be able to explain how the light reactions of photosynthesis generate the NADPH and ATP that are consumed when glucose is synthesized from CO₂ in the Calvin cycle.In what way are the light reactions similar to electron transport in mitochondria; in what way are they different?

Answer 1

The light recation differ from mitochondria by following way:

Charcteristics	light phase	Mitochondrial
1) Presence of photosystem 1 and 2	Present	Absent
2) Light energy involved	Yes	No
3) Reactants	water, NADP+	Oxygen, NADPH and FADH2
4) Products	Oxygen, electrons and NADPH	Water, NADP+ , FAD+
5) ATP synthesised	yes	yes
6) Electron transport takes place in	Thylakoid membrane	Mitochondrial inner membrane
7) Quinone used	Yes	No
8) Cytochrome	Cyt-b6f	Cyt-C1
9) Ferrodoxin	Present	Absent
10) Proton gradient accumulated in	thylakoid lumen	Intermitochondrial membrane space
11) The proton backflow to	Stroma	matrix