osmosis question

[DrSpeed]

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the contractile vesicle of an aquatic species decreases its rate of contraction when moved from fresh water to sea water. This is explained by:

I said: a decrease in osmotic pressure of the environment.

Solutions guide says it due to an increase of osmotic pressure of the environment.

Is that a misprint or am I mistaken on the concept of osmotic pressure? doesnt it decrease as solute is added to solvent?

 

[baedero1]

is this question from destroyer?

 

[DrSpeed]

no, Kaplan

 

[bryantje]

If you think back to colligative properties, osmotic pressure is proportional to the molarity of the solution. If the molarity increases, so does the osmotic pressure. A move from freshwater to saltwater is an increase in salt's molarity. A tricky question, as I also am often confused by osmosis questions (usually due to poor wording!).

 

[whawha]

the contractile vesicle of an aquatic species decreases its rate of contraction when moved from fresh water to sea water. This is explained by:

I said: a decrease in osmotic pressure of the environment.

Solutions guide says it due to an increase of osmotic pressure of the environment.

Is that a misprint or am I mistaken on the concept of osmotic pressure? doesnt it decrease as solute is added to solvent?

If you go from fresh water to salty sea water, the osmotic pressure has increased. (Sea water is more concentrated than fresh water)

So, in order not to lose much water, it will decrease its rate of contraction.