please i need to understand more about water potential and osmosis

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osmosis and water potential

Posted Wed 11th April, 2012 @ 11:23 by ifeoma egbuniwe

4 Answers

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<This is based on teaching off AQA  AS BIOL1 spec.>

Osmosis is the movement of water from an area of higher water potential (less negative) to an area of lower water potential (more negative) through a partially permeable membrane.

Therefore, during osmosis, water moves down the water potential gradient.

Water potential: the highest water potential is zero. All solutions will have a water potential value less than zero (ie. they all have a negative water potential value). The closer the water potential value is to zero, the higher the water potential.The more negative the value becomes, the lower the water potential.

Answered Wed 11th April, 2012 @ 14:32 by clarenceofcydonia
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I have made a very good revision notes on unit 1 biology which includes water potential and osmosis. Ill explain it here but you can can look at the link below.

http://getrevising.co.uk/resources/summarised_notes_on_cells_lungs_heart_and_digestion

First you need to know the definition of osmosis:

"Osmosis is the passive movement of water molecules from an area of high concentration to low concentration through a partially permeable membrane."

The parts i have put in bold are where you get your marks!

Next the definition of osmosis in terms of water potential:

"Osmosis is the passive movement of water molecules from an area of high water potential to an area of low water potential through a partially permeable membrane."

They might ask you to define osmosis using water potential and this is essentially the same principle ===> If you have a high water potential on one side and on the other side a low water potential then particles from the high water potential will leave and go to the low water potential to reach equalibrium (equal on both sides) soooo...... just replace concentration with water potential as i have done above.

One thing you might need to know is that pure water (i.e distilled water) has a water potential of 0. Therefore anything else like juice will have a negative water potential. So as explained by clarence above  the more negative the value becomes, the lower the water potential.

Hope i helped   =)

Answered Thu 12th April, 2012 @ 15:12 by Braniac
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I have made a powerpoint on osmosis etc its for OCR I hope it helps B-)

http://getrevising.co.uk/resources/ocr_osmosis_powerpoint

Answered Thu 12th April, 2012 @ 18:33 by Abby
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http://getrevising.co.uk/resources/aqa_as_biology_unit_1_cells_and_movement_in_and_out_of_them

Hey I made these notes when I was doing my AS Levels last year. I hope they help :) **

Answered Thu 12th April, 2012 @ 19:09 by Alice Clare