• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

Osmosis is a "type of diffusion where water passes through a semi-permeable membrane from where water is in high concentration to a low concentration

Extracts from this document...


Information Osmosis is a "type of diffusion where water passes through a semi-permeable membrane from where water is in high concentration to a low concentration." A French scientist (Jean-Antoine Nollett) discovered osmosis in 1748. He discovered it by filling a pig's bladder with alcohol. This was then placed in water for several hours. The water had moved into the pig's bladder but very little alcohol had moved out. The pig's bladder was a semi-permeable membrane. The particles in a liquid are constantly moving. When small particles or water molecules meet a semi-permeable membrane they may pass through. But larger particles, like glucose cannot get through the membrane at all. If there is a high concentration of water molecules on one side of the membrane, then water molecules will pass through the membrane and the water appears to have moved through the membrane to the lower concentration. ...read more.


This is called "Hydrostatic pressure" it works against osmosis. But when plants are faced with a low concentrated water solution (sucrose) the will lose water and become flaccid. Which is the opposite of turgid. So the plant cell will shrink instead of grow. When a plant is placed in an equal concentration solution between water and sugar then the plant will be "in between being turgid or flaccid" so the plant won't shrink but neither will it be able to raise it's leaves in the sunlight. So the plants favour a high concentration of water. Animal cells don't have cell walls so when placed in a pure water solution they may well swell up and burst because there is nothing to support the cell membrane. ...read more.


The level on the higher concentrated side of the membrane will rise whilst the level on the less concentrated side will fall. When the concentration of water is the same on both sides, the movement of water will stay the same in both directions. So now the system is equal. The concentrations of sugar solution depend on the amount of water present. The more distilled water present, the less sugar solution present. The Sucrose has a low concentration of water. So when water is added it will diffuse into the sucrose, diluting it. If more Sucrose is in the container then the diffusion won't happen as much. With 10 millilitres of sucrose and 0 millilitres of pure water it is "a region of low concentration of water." This is because there is much less water. The solution is pure Sucrose because there is no water present to dilute it. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Green Plants as Organisms section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Green Plants as Organisms essays

  1. Osmosis is the movement of water from a region of high concentration to a ...

    When colliding with the membrane the water exerts a pressure, this is called the water potential. Pure water has a water potential of zero. When solute is added to the water, the sugar molecules get in the way of the water and reduce the number of collisions taking place, therefore causing a lower water potential.

  2. What effect does the sucrose concentration have on osmosis?

    Evaluation Overall, the investigation went really well. Having carried out a preliminary experiment, I was in a position to make justified changes if necessary and therefore approach the task more efficiently. I think that the practical was carried out well by my group and the results I obtained were very accurate.

  1. Determine the water potential of potato tuber cell with the varying affect of solute ...

    the concentration of water is much less on the outside than on the inside of the potato tuber cell. Since in osmosis water always moves down the concentration gradient, it means that more water will move out of the cell since there is less water in the solution.

  2. Water moves from a high concentration gradient of water to a low concentration of ...

    Turgid Normal Plasmolysed Concentration of diluted sucrose solution (m) Prediction 0 There is no sucrose in the water therefore water will go in rapidly to the potato by osmosis, since the outer concentration gradient of water is higher than the inner concentration gradient.

  1. The aim of the investigation is to find the exact concentration of the cell ...

    The water particles do actually move in the other way as well but because more travel in the other direction this not noticeable. Even when equilibrium occurs the particles keep crossing but they are moving equally each way. Variables There are many things that could be changed in this investigation

  2. Osmosis is the passage of water from a region of high water concentration through ...

    Palimery test:- Length of time: 45 minutes Borer size: 3 Chip size: 30mm Container: test tube Solutions size: 10ml Solutions used: 0.0m and 1m Statues of test: successful Apparatus:- Bore size 3x1 Patatox1 Test tube x6 Sugar solutions 0.0m - 1m Knife x1 Ruler x1 Method:- 1)

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work