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.
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Question

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.
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Accepted Answer

Hi everyone. Here's our next question. How does a concentrated salt solution preserve meat? To avoid food spoilage. Let's recall if we're going to avoid food spoilage that we are concerned about bacteria or fungi growing in our food. So we need to prevent that from happening. And now let's imagine a bacterial cell or a fungal cell. It has a certain salt concentration. Now imagine a very high salt concentration and the outside in our solution with a lower salt concentration inside our bacterial or fungal cell. Well what happens in this situation? We have water diffusing out of this cell by osmosis to try and equalize this concentration. So with that vision in mind let's go through our answer choices. Choice A. Says. It makes the cell wall of fungi. Turgid turgid is water pressure sort of causing the cell to bulge from the inside that occurs when water is diffusing into the cell. That's the exact opposite of what's happening here. So Choice A. Is not correct. Choice B. Says it kills the bacteria by making the inside sell more water concentrated. Um Well that's not correct. We have water diffusing out of the bacterial cell not becoming more water concentrated. So that's not correct. Choice C. Says it eliminates the bacteria by introducing salt in its cell cytoplasm. Well cells control very carefully salt the coming of salt in and out. It cannot come in on its own. Um Due to the fact it's ions it has to be transported through transporter proteins which are very carefully controlled by the cells. Salt will not be going into the cell water will be osmosis out, So Choice C. Is not correct. So we're down to Choice D. It makes the bacteria or fungi become plasma wised. Well, this is our correct answer, because plasma realized is what happens when too much water diffuses out of the cell and the cell shrivels up and dies and that's exactly what happens with this very high salt concentration outside. Just tons of water keeps diffusing out, trying to equalize this and your bacterial cell, your fungal cell will eventually shrivel up and die. Since it prevents the kills off the bacteria fungi, it will avoid food, spoilage and preserve meat. So Choice D. Is our correct answer here. See you in the next video.

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Key Concepts

Aquaporins

Mercury's Mechanism of Action

Osmotic Swelling