if something happened to a paramecium that caused its contractile vacuole to stop contracting?

Question

what would you expect to happen? would this result occur more quickly if the paramecium was in water with a high salt concentration or in water with a low salt concentration? why?

Answer 1

1.) High salt in cytoplasm of paramecium and low salt out side (fresh water) makes water flow into the paramecium to dilute him. Naturally he resists this by pumping out the excess water with his contractile vacuole. If that vacuole stopped pumping him out the paramecium would keep taking on more water until he burst.

2.) If you place the paramecium in a salty solution less salty than the its cytoplasm the difference in osmotic will be less, but water will still move inside, but at a slower rate. So the creature will still pop without his contractile vacuole but it will take longer to happen.

3.) If you place the paramecium in a really briny salt solution that is much more salty than his cytoplasm the water inside will move out to dilute the brine. The paramecium will loose much of his water (until the osmotic pressure inside and out equals) and will not pop. He may of course die of dehydration instead.

It is my assumption that your question indicates situation 1 VS 3, but keep 2 in mind since “salt water” in no way clearly indicates how much salt relative to his cytoplasm.

Answer 2

I'd expect it to die.

Doug