Question

1.      Identify the treatment that demonstrated the highest photosynthetic rate. Explain why you think this is. (2 points)

	Time (minutes)
Treatment	0	2	4	6	8	10	12	R-Value	Slope
U	0.683	0.201	0.102	0.132	0.136	0.065	0.125	0.4744	-0.0341
UC	0.156	0.066	0.054	0.066	0.053	0.06	0.069	0.339	-0.0049
F	0.561	0.329	0.155	0.45	0.235	0.436	0.305	0.0694	-0.0085
D	0.329	0.498	0.321	0.327	0.327	0.32	0.153	0.4621	-0.0157
B	0.443	0.149	0.295	0.437	0.404	0.328	0.317	0.0045	0.0016

2.      What was the purpose of running this experiment on thylakoids with no dye (UC) and dye without thylakoids (D)? (2 points)   

3.      What effect did boiling have on photosynthetic rate? Explain why you think this occurred. (2 points)

4.      What effect did darkness (foil) have on photosynthetic rate? Explain why you think this occurred. (2 points)

Answer 1

1) Unboiled treatment shows high photosynthetic rate as the electron acceptors and functional reaction center is present.

2) The experiment was performed to study Hill reaction, the light dependent photosynthetic reactions and to measure the amount of NADP reduced to NADPH. In the experiment, a blue dye DCPIP (2,6-dichlorophenol-indolphenol) is used that accepts elctrons and reduces NADP and turns to colorless state, through which NADP reduction can be measured. This was done by isolating thylakoid and combining it with the dye and exposed to light.

(Blue) DCPIP(oxidized) + 2e^- ──> DCPIP(reduced) (Colorless)

3) Boiling decreased the low photosynthetic rate, it may be due to the distortion of the electron acceptors and hence photosynthesis rate lowers.

4) Darkrness lowers the speed of photosynthetic reactions as it is initiatedthrough absorption of photon by p680 reaction center.