Lab 5: Photosynthesis & Vibrio Colony Re-streak

What would happen to the rate of NADPH production if we disrupted the proton gradient across the thylakoid membrane? (So instead of the thylakoid lumen/space having a pH of 5 it is closer to a pH of 7).

 

It would have no effect on the rate ofNADPH production

It would increase the rate of NADPH production

It would decrease the rate of NADPH production

It would increase the rate of NADPH production

The two molecules shown below differ only by the presence of two hydroxyl groups in zeaxanthin. Which do you expect to migrate faster (larger Rf) using the same paper chromatography conditions as in this week’s lab?

 

Beta-carotene

 

Zeaxanthin

Beta-carotene

You are measuring DCPIP reduction in isolated chloroplasts in the dark and also with light exposure. Your results are shown below:

What is the light-dependent rate of DCPIP reduction? Do NOT include units in your answer. 

0.7

You are on Part IV and need to calculate the volume of the enriched chloroplast suspension (from Tube "E") that you need to add to 5 mL of cold sucrose buffer to get a standardized suspension of 0.15 mg chlorophyll/mL. You follow steps 1-8 in the procedures and measure an absorbance of 0.4 in Tube "L".

From the absorbance value, first calculate the concentration of chlorophyll in Tube "E" (C_x). Then use that value to calculate the volume of Tube "E" (V_x) you need to add to 5 mL of buffer to get the standardized 0.15 mg chlorophyll/mL.

Enter your answer for V_x (in mL) Do NOT include units and round your answer to the nearest hundredths--2 places after the decimal. 

1.22

In a plant, when light excites a chlorophyll molecule in the light harvesting complex (antennae) of a photosystem in an intact chloroplast, that energy is released primarily by

 

the reduction of DCPIP

 

the emission of fluorescent red light

 

the oxidation of the specialized Chlorophyll a dimer pair in the reaction center

 

resonance energy (excitation energy) transfer to another pigment molecule

resonance energy (excitation energy) transfer to another pigment molecule

In the paper chromatography experiment in Part III of the lab, select the best statement regarding the expected migration of chlrophyll a compare to chlorophyl b:

 

Chlorophyll a is less polar than chlorophyll b and as such would migrate faster than chlorophyll b (larger Rf value for chlorophyll a).

 

Chlorophyll a is more polar than chlorophyll b and as such would migrate slower than chlorophyll b (smaller Rf value for chlorophyll a).

 

Chlorophyll a is less polar than chlorophyll b and as such would migrate slower than chlorophyll b (smaller Rf value for chlorophyll a).

 

Chlorophyll a is more polar than chlorophyll b and as such would migrate faster than chlorophyll b (larger Rf value for chlorophyll a).

Chlorophyll a is less polar than chlorophyll b and as such would migrate faster than chlorophyll b (larger Rf value for chlorophyll a).

You are on Part IV and need to calculate the volume of the enriched chloroplast suspension (from Tube "E") that you need to add to 5 mL of cold sucrose buffer to get a standardized suspension of 0.1 mg chlorophyll/mL. You follow steps 1-8 in the procedures and measure an absorbance of 0.29 in Tube "L".

From the absorbance value, first calculate the concentration of chlorophyll in Tube "E" (C_x). Then use that value to calculate the volume of Tube "E" (V_x) you need to add to 5 mL of buffer to get the standardized 0.1 mg chlorophyll/mL.

Enter your answer for V_x (in mL) and include only two places after the decimal and no units (eg. 1.48).

1.1