BIO question

[299678]

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If an amoeba is isotonic with a solution that is hyper-tonic for a crab, into which organism wil water show a net flow ehn these organisms are immersed in the solution?
a) amoeba
b) crab
c) neither
d) both

Need your explanation to support your answer

 

[Avery07]

If an amoeba is isotonic with a solution that is hyper-tonic for a crab, into which organism wil water show a net flow ehn these organisms are immersed in the solution?
a) amoeba
b) crab
c) neither
d) both

Need your explanation to support your answer

The solution is isotonic to the amoeba meaning that it has the same water concentration. Because of both the amoeba and the solution having the same concentration of water, there will be no net movement of water.

The solution is hypertonic to the crap meaning that it has a higher concentration of solutes than what is inside the crab cells. Because the solution has a higher concentration of solute, the water will have a net flow out of the crab cells and into the solution via osmosis.

Water Flow
Solution <-----> Amoeba (no net flow)
Solution <------ Crab (net flow into solution)

So the answer will be C) Neither.

 

[sfoksn]

is there a typo in the question?
what is ehn?

 

[Erhatstil]

depending on how much water flows from the crab into the hypertonic solution, i think eventually there could be a net flow into the amoeba. though the amoeba starts out isotonic, the solution becomes hypotonic as water leaves the crab and would enter the amoeba. so both species would see a net flow. out of crab, then into amoeba.

 

[sfoksn]

yeah. i thought the answer would be both too, but then the question is not very clear. it doesn't really tell you exactly what is going on.

 

[299678]

Thank you
I didn't catch the word "into" when I solved this problem

 

[Avery07]

depending on how much water flows from the crab into the hypertonic solution, i think eventually there could be a net flow into the amoeba. though the amoeba starts out isotonic, the solution becomes hypotonic as water leaves the crab and would enter the amoeba. so both species would see a net flow. out of crab, then into amoeba.

Thank you
I didn't catch the word "into" when I solved this problem

So what is the correct answer? Does the answer imply each organism with the water individually or would it imply the crab's effect on the amoeba?

 

[AmpedUp]

Weird & annoying question to ask on the author's end (not the OP 😀). Absolutely hate questions like this, because they're just out to trick you...

My Answer
B. Crab

No net flow between amoeba and solution...technically, there's flow in both ways, but they equalize eachother in both directions, which is "no net" flow

In crab, there's a "net flow" when the solution moves from hypotonic to hypertonic (or high to low concentration of whatever this solution is)

Btw where did you find this question? Kaplan?

 

[299678]

It came from ADA 2009 sample test. I waited for 2 months to get this. Can you believe that? anyway, the right answer is no net flow for both

 

[AmpedUp]

It came from ADA 2009 sample test. I waited for 2 months to get this. Can you believe that? anyway, the right answer is no net flow for both

oh ok the "into" part threw me off, as someone suggested in this thread. So yes, I can see how "both" is the correct answer. Nothing is going into the crab (it's hypotonic to its environment, and moves outside toward the hypertonic portion)...I guess that means no "net flow" according to their question stem? and what's going into amoeba is equal to what's going outside of it; therefore, no "net flow" for this as well.

why does ADA put duds on their sample tests? chea!! This question isn't cool at all...