Questions tagged [osmosis]
The process by which a solvent, especially water, tends to flow towards areas of higher solute concentration.
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Why is a urea solution hypotonic relative to RBC?
If I place a RBC in 0.5M urea we see haemolysis.
My textbook says that "the solution is hypotonic. Urea enters the RBC down it's concentration gradient. Water follows the movement of urea by osmosis. ...
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1answer
67 views
Osmosis- basic questions [closed]
Hi there,
For the first picture: can someone please explain in simple terms (I started learning biology a few days ago), why the answer to this osmosis question is no?
For the second picture: The ...
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1answer
34 views
Confused about definition of bulk flow of water by osmosis
As a teacher of high school and introductory college chemistry, I used textbooks that defined osmosis as a flow of water (only) through a membrane that prevents other substances such as dissolved ...
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1answer
24 views
Osmosis vs protein-binding in preserving foods through salting
I had assumed that the preservative function of covering foods with NaCl or brine was due to osmosis killing the microorganisms on the food by dehydration. However, I am now wondering to what extent ...
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1answer
58 views
Osmotic Pressure Clarification
My textbook states that the higher concentration of solutes, the greater the osmotic pressure will be and the greater the pull of water in will be. However, osmotic pressure is defined "as the ...
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0answers
40 views
Why does solute potential go up as temperatures go down?
So the closer a solution's solute potential is to zero, the more water potential said solution would eventually have. The solute potential equation is -iCRT. If the temperature is 0, -iCRT would be ...
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53 views
Why does blood come out of leach when salt is put on it?
I know osmosis is the reason for the water to come out of cells - When you sprinkle salt over a leech, it creates concentration gradient and forces the water out of the cells. But why does a lot of ...
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57 views
Does high concentration of salt kill chitin protected parasitic eggs?
Parasitic eggs of some parasites protected by chitin that makes them highly survivable (even in acidic environment of stomach). What about high concentration of salt in water - does it kill chitin ...
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1answer
174 views
Osmosis in red blood cells and bacteria
This is a question from an exam in my biology course.
Bacterial cells and human red blood cells were inserted into one solution. Upon testing one hour later the blood cells exploded, while the ...
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58 views
How can “muscle fullness” be achieved with electrolytes?
Muscle fullness or the "pump" is a common goal among physique or bodybuilding competitors. Carbohydrate-loading is one way they can look dense during competitions but electrolyte manipulation also is ...
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1answer
208 views
Why don't cells of aquatic animals burst?
We know that if we keep plant cells in water, they don't burst because of a cell wall. But the cells of aquatic animals lack cell walls but they still survive. Why?
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Why does there exist osmoconformers in salt water?
I understand that there does there does not exist osmoconformers in fresh water as water from the environment would move into animal cells, leading to lysis. But wouldn't the opposite be true for salt ...
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Osmotic Pressure in Capillaries [closed]
In this diagram, D is apparently the point at which "the osmotic pressure into the capillaries is the greatest", but I cannot figure out why. Any help would be much appreciated!
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when does osmosis stop
I have a question about osmosis that goes a bit deeper than most basic textbooks so I cannot find the answer.Here's the problem:
Imagine an animal cell, say a red blood cell, in a slightly hypotonic ...
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1answer
1k views
Can I kill bacteria with distilled water?
Given that bacteria are hypertonic (contain more salts) compared to distilled water, and that they rely on ion concentration differences across the plasma membrane to survive, can I kill a bacterial ...
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0answers
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Why is ethanol osmotically active if it can enter through the plasma membrane easily?
This has been bugging me for a while, and I can't seem to find an answer to it, and I am sorry if I am asking a lot with this question(s). Firstly, I keep finding sources suggesting that ethanol is ...
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1answer
158 views
Can saltwater fishes survive in sugar solution?
I know saltwater fishes can't survive in freshwater because of osmosis that water would rush into the body of fishes. How about sugar solution? Does sugar solution provide similar conditions as salt ...
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2answers
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Does osmosis require a protein channel?
Earlier today, I undertook an exam which featured a question regarding the stickiness of mucus in a person diagnosed with CF's. We had to explain why they had stickier mucus than a 'normal' person, ...
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While preparing Jam we use sugar.Why? (can you elaborate in science language) [closed]
Actually I was trying to find out the basic necessity of adding sugar in preparing jam.
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1answer
694 views
How does an isotonic environment affect fish? [closed]
Fish receive oxygen needed from water that passes through their gills. If fish were isotonic to their watery environment, what problems would this pose to them?
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Why do stomata close in salt water?
Why do the guard cells of the stomata close when they come in contact with salt water?
I recognize it has something to do with osmosis and the fact that osmosis makes the water drain in some sort, ...
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0answers
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Solute potential of sucrose relative to NaCl
Does 1M NaCl or 1M sucrose solution have a more negative solute potential?
I was thinking that for the same volume of solution, (eg 1 dm^3) there will be 2 mol of ions in NaCl solution and 1 mol of ...
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3answers
12k views
Why does a high osmotic pressure pull water in, yet a high hydrostatic pressure pushes water out?
When I normally think of high pressure, I think of it as pushing something away from the zone of high pressure.
Yet for a high osmotic pressure, water is pulled IN to this high osmotic pressure ...
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1answer
318 views
What are internal and external osmotic pressures when referring to a cell?
I've seen the term used but cannot find a clear answer:
What are internal and external osmotic pressures when referring to a cell?
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I am not understanding how water passes through root hair cells
Why do people say that water moves into the cell because the water concentration of the cell sap is low ? the cell sap is surrounded by a membrane so if any water moves into the cell it must be ...
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1answer
2k views
Why does NaCl react differently with a boiled potato and with a raw one
Well my question is based on this question down below.
For those who don't speak german:
You have two potato slices one of them is boiled the other one is just raw.
Now you scatter some salt over ...
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0answers
167 views
“Imperviate” is it a word what can be substituted? [closed]
Sentence:
The aquaporins allow water to pass through the membrane and imperviate any solute molecules from diffusing across.
I'm looking for a word that pretty much is the opposite of perviate or to ...
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1answer
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Why do we have wrinkly fingers after swimming?
I found an explanation for my question here http://www.pitara.com/science-for-kids/5ws-and-h/why-do-we-have-wrinkly-fingers-after-swimming/, which suggests that water washes out sebum (special oil, ...
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2answers
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How does the peptidoglycan layer of a bacterial cell wall help prevent osmotic lysis? [duplicate]
I recently read that penicillin works by damaging the peptidoglycan layers of a bacterial cell wall causing osmotic lysis, which is when the bacteria cell bursts due to osmotic pressure.
I just ...
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1answer
798 views
What would kill you first water or cola? [closed]
After discussing this with some colleagues, I devised the theory that you could drink more coca-cola in a single sitting than you could water, without killing you.
Defining the volume it would take ...
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0answers
107 views
Do hydrogen ions contribute to water potential?
I was thinking about lysosomes and how they maintain an acidic pH inside themselves by pumping H+ ions from the cytosol. Do hydrogen ions set up a concentration gradient that causes water to move by ...
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50 views
Oncotic (Osmotic Pressure) in the blood pressure
I just wanted to ask, why is the oncotic pressure more negative in the blood plasma even though the hydrostatic pressure is higher since the blood comes from the pumping of the heart?
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1answer
557 views
Why is it not advisable for humans to drink distilled water? [duplicate]
Distilled water is pure and it does not contain any minerals, so may not be advisable for drinking.
Although laboratory made distilled water is completely pure, industry made water may still contain ...
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1answer
653 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
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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 ...
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1answer
429 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
177 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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1answer
2k 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
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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
781 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
2k views
What happens to the red blood cell in CaCl₂ 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?
...
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1answer
32k 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?
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2answers
6k 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
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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 ...
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1answer
451 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 ...
