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1answer
42 views

Why is the swelling of bread when placed in water not considered to be caused by osmosis? [closed]

Why is bread swelling up when placed in water not considered to be caused by osmosis? Is there a property of water that should make it leave the bread instead of enter?
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1answer
65 views

Osmolarity vs. Tonicity

We're learning about osmoregulation in AP Biology and the terms Tonicity and Osmolarity are really confusing me. I watched this video on Khanacademy to try to understand what the difference is, and ...
5
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1answer
48 views

Do saltwater fish need to drink? [duplicate]

In my biology class we got the question if saltwater fish need to drink. We need to use the term osmosis, but I cannot think of a valid answer and we were allowed to ask help.
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1answer
51 views

Trees ability to transport water [duplicate]

How can trees be able to transport hundreds of liters of water all the way up to the crown and out in the leaves?
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0answers
25 views

Experiments on effects of RBC in solutions of different tonicity

In hypotonic solution, it appeared to be clearly visible, hemoglobin accumulated at the bottom of tube. For isotonic, it wasn't clear and hemoglobin settled on the bottom. And hypertonic, it appeared ...
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1answer
304 views

When does DIFFUSION occur and not OSMOSIS, and the otherwise?

For example, I do know that red blood cells have both the Na+/Cl- co-transporter and Aquaporin (water channel) that allows both Na/Cl and water molecules to pass through. But why in biology textbooks ...
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1answer
19 views

Is the PCT of the nephrons of the kidneys of marine vertebrates to minimize the natural tendency for exosmosis?

For marine vertebrates, the concentration of salts outside their body (in the water, that is) is more than that inside their body. So, there is a natural tendency for exosmosis to occur. To minimise ...
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2answers
85 views

Osmotic Pressure and Enzyme Activity

Is it true that in an enzyme-catalyzed reaction, the rate of reaction does not vary with varying osmotic pressure? Instead of just a true or false answer, why does it, or why does it not vary with ...
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1answer
706 views

What happens to the red blood cell in CaClâ‚‚ solution?

Here's the problem: One red blood cell is placed in a hypertonic solution of NaCl, another is placed in a solution of CaCl2 equimolar with the NaCl solution. What would you expect to happen and why? ...
3
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1answer
8k views

What is the difference between osmotic potential and osmotic pressure?

Which term is used to calculate water potential? Does osmotic potential mean the same as solute potential?
3
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2answers
967 views

Does osmosis take place in prokaryotic cells?

As far as I know, osmosis occurs in Eukaryotic cells, and I'm wondering if it could take place in prokaryotic cells too.
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2answers
5k views

Diffusion of Hypotonic solution into solution with glucose and starch

Cell walls are selectively permeable to ions and organic molecules. Sometimes the selectivity is passive and a reflection of the physical laws governing diffusion. We can do simple experiments that ...
5
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1answer
161 views

How does a Na+/H+ antiporter drive osmosis in this “osmotic motor”?

This recent paper in Cell describes a cancer cell using osmotic pressure to move in confined spaces. The cell preferentially inserts Na+/H+ antiporters in the leading membrane. I want someone to ...