Kobebucsfan

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Sea water and fish tissues have different ion concentrations, what happens to a freshwater fish as it swims into a saltier water ?

does it gain or lose ions through its gill epithelia ??
 

403710

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Well freshwater fish are hypotonic to the salt water, meaning they have less of an ion concentration within them. Therefore, water will leave them through the gills and they will dehydrate.

As far as what happens to the ion concentration... Is that an actual question somewhere or a curiosity question of your own? I don't think the ions move. Ions stay in place within the blood of the fish, gills, etc. they are behind membranes (selectively permeable) are they not?

Let me know if this helps or if you have a different answer, I'm fairly confident on this.
 
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Kobebucsfan

Kobebucsfan

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Apr 20, 2010
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Well freshwater fish are hypotonic to the salt water, meaning they have less of an ion concentration within them. Therefore, water will leave them through the gills and they will dehydrate.

As far as what happens to the ion concentration... Is that an actual question somewhere or a curiosity question of your own? I don't think the ions move. Ions stay in place within the blood of the fish, gills, etc. they are behind membranes (selectively permeable) are they not?

Let me know if this helps or if you have a different answer, I'm fairly confident on this.
its an actual question from a book. choices r either gain or lose
 

403710

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Ah maybe here's some light - if water is expelled, ion concentration increases simply because concentration is inversely proportional to volume of water. Bam. Is that right
 
Apr 7, 2012
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It should gain ions through osmosis. 1. It will gain ions from salt water. 2. Ion concentration will increase due to loss of water. Hope this helps. Good luck.
 

dsoz

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No, it will not gain ions through OSMOSIS. It will gain ions through active transport, facilitative diffusion, or just plain diffusion, but not OSMOSIS (the movement of WATER through a semi-permiable membrane from an area of low solute concentration to an area of high solute concentration).

The concentration of the cells will increase. Just like an above poster stated, because of water loss from cells and some slight diffusion or active transport on the cell membrane.

dsoz