Dec 12, 2013

Sample STPM Semester I Question

ATP and NADPH are two main molecules which are required for the production of carbohydrate in plants. Describe how these molecules are generated during photosynthesis.

[9 marks]

P680/Photosystem II absorb light energy/photon.
Energy is passed from one pigment molecule to another pigment molecule until reach the reaction centre.
The electron is excited and captured by primary electron acceptor.
Created electron hole in P680/photosystem II.
Which filled up by electron from photolysis of water
Primary electron acceptor passes the electron to a series of electron carriers/plastoquinone, cytochrome complex and plastocyanine
Energy released in the form of ATP through chemiosmosis
P700/photosystem I absorbs light energy/photon
The electron excited and captured by primary electron acceptor
Electron is passed to ferredoxin
NADP+ is reduced to NADPH.