SCIENTIFIC THINKING Mercury is known to inhibit the permeability of water channels. To help establish that the protein isolated by Agre's group was a water channel, the researchers incubated groups of RNA-injected oocytes (which thus made aquaporin proteins) in four different solutions: plain buffer, low concentration and high concentration of a mercury chloride (HgCl2) solution, and low concentration of a mercury solution followed by an agent (ME) known to reverse the effects of mercury. The water permeability of the cells was determined by the rate of their osmotic swelling. Interpret the results of this experiment, which are presented in the graph below. Control oocytes not injected with aquaporin RNA were also incubated with buffer and the two concentrations of mercury. Predict what the results of these treatments would be

Verified step by step guidance

1. Observe the graph which shows water permeability (rate of osmotic swelling) for different treatments of oocytes.
2. Note that oocytes in buffer have the highest water permeability, indicating normal aquaporin function.
3. Oocytes in low HgCl2 show reduced water permeability, suggesting that mercury inhibits aquaporin function.
4. Oocytes in high HgCl2 have even lower water permeability, reinforcing the inhibitory effect of mercury on aquaporins.
5. Oocytes in low HgCl2 and ME show restored water permeability, indicating that ME reverses mercury's inhibitory effect on aquaporins.