Questions tagged [osmosis]

The process by which a solvent, especially water, tends to flow towards areas of higher solute concentration.

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Which single substance among Potassium and Phosphate has the greatest osmotic activity in the Intracellular fluid?

My physiology textbook mentions that potassium has the greatest concentration ( 155 mEq/L ) in the Intracellular fluid and that I thought would make it the most osmotically active but the answer given ...
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Calculation of solute, pressure and water potential

What would be the water potential (Ψw), solute potential (Ψs) and pressure potential (Ψp) at equilibrium when a cell with Ψs= – 0.7 MPa and Ψp= 0.7 MPa is placed in a solution with Ψs= – 0.5 MPa? (...
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Transpiration and Water Uptake

I know that water moves into the root hair cells from the soil via Osmosis down the water potential gradient and then this water travels through diffusion and osmosis through the symplast pathway ...
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Why does the time to reach equilibrium across a membrane decrease with concentration?

We're learning about flux and Fick's law and there's one point I'm having trouble understanding. Assuming we have a higher concentration of a species on one side of a membrane, I understand that ...
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Why is movement of water through cell walls considered the apoplast and symplast pathway?

Why would the movement of water through cell walls be considered the apoplast and symplast pathway? I understand why it's considered the apoplast pathway (as the water is moving through a non-living ...
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Osmotic pressure and turgor pressure details

I am a high school student and I am very confused in how we define osmotic pressure? Osmotic pressure is defined as the pressure required to stop the diffusion of solvent into a solution by applying ...
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Plasmolysis and turgor pressures

I am a high school student and I am a little confused in plasmolysis, when we study plasmolysis, we say that at limiting plasmolysis, the turgor pressure OR pressure potential reduces to 0 what do we ...
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1 answer
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Why does water flow from low to high concentration? Shouldn't it be the reverse? [closed]

So my understanding of water flow is as follows: Basically, water moves about randomly because it has thermal energy. It will occasionally hit other water molecules and "bounce" back. As ...
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1 answer
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Giving a sign to Pressure Potential, Osmotic Potential And Other Similar Quantities

When these quantities are mentioned with what reference do we give signs to them? Why is Osmotic Pressure positive, but Osmotic Potential, negative? What about Turgor Pressure (Pressure exerted by the ...
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Is osmosis diffusion of water?

My textbook says this: Osmosis is the diffusion of water. Wikipedia says this: The diffusion model of osmosis is rendered untenable by the fact that osmosis can drive water across a membrane toward ...
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How does imbibition and turgor pressure generate much force?

Both imbibition and turgor pressure together create a large force in plants such as force required to burst the seed coat open?
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same osmotic pressure of different solution

For example, There is a sugar solution with concentration $A_{1}$, how to determine the concentration of a NaCl solution which produce same osmotic pressure as the previous sugar solution toward ...
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Speed of electric signal vs chemical diffusion

I'm currently reading the book, "An Introduction to Nervous Systems" by Ralph J. Greenspan. On page 20, there is a sentence that confused me. It was, "Electrical signaling has the advantage of being ...
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Water potiental

I think solution x should be present at Z as this solution has moved out of cell causing cell to be plasmolysed but the answer is Y. How?
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Question about osmosis

The concentration of water outside potatoes B and C is more than the concentration of water inside the potatoes. So water will flow inside the potato. Now, since the concentration of water in the ...
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Osmosis/ Facilitated diffusion

Water can move across the (Semipermeable non polar lipid) membrane by simple diffusion (osmosis). But polar molecules cannot pass through the non polar lipid bilayer, they require carrier proteins to ...
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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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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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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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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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3 votes
1 answer
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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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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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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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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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1 answer
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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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1 answer
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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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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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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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4 votes
1 answer
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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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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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1 answer
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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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2 answers
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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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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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5 votes
3 answers
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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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1 answer
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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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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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1 vote
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"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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7 votes
1 answer
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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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2 votes
2 answers
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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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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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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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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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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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1 answer
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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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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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6 votes
1 answer
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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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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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