What experiment can you plan to answer these questions?

Choose between possible and wrong. 
Examine ALL answers. 
Go from A to D
A.You can add dinitrophenol (a chemical reagent that inhibits cellular proton pumps) to the cells immediately after their exposure to stained yeast. 
We could then microscopically monitor  the pH changes within the food vacuoles, as previously described (Figure 1).

B. You can determine the existence of proton pumps in the food vacuoles directly. 
First isolate the food vacuoles at various time points following their exposure to the stained yeast. This can be done after cell lysis, using sucrose gradient centrifugation. 
The presence of proton pumps in the food vacuoles collected at the various time points is then determined using a variety of antibodies, which specifically recognize paramecium proton pumps.

C. You can isolate the mRNAs found in the food vacuoles, and determine if any encode a proton pump.

D. You can search the paramecium’s genome for a gene similar to known genes encoding proton pumps. Finding such a gene will prove that this pump is responsible for the pH changes observed.

After examining ALL the answers, you may continue to the next question.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

.