Can anyone tell me what osmosis is?

Question

I need to know for my science project.

Answer 1

Yes, it's the diffusion of water from high concentration to low concentration through a semi-permeable membrame.

Answer 2

Osmosis is a physical process in which a solvent moves, without input of energy, across a semipermeable membrane (permeable to the solvent, but not the solute) separating two solutions of different concentrations.[1] Osmosis releases energy, and can be made to do work, as when a growing tree-root splits a stone.

Answer 3

Osmosis: the movement of water molecules from an area of high concentration to an area of low concentration through a semi-permeable membrane.

Answer 4

Osmosis is the passage of water from a region of high water concentration through a semi-permeable membrane to a region of low water concentration.
The Consequences of Osmosis

Firstly what happens to plant cells:

Plant cells always have a strong cell wall surrounding them. When the take up water by osmosis they start to swell, but the cell wall prevents them from bursting. Plant cells become "turgid" when they are put in dilute solutions. Turgid means swollen and hard. The pressure inside the cell rises, eventually the internal pressure of the cell is so high that no more water can enter the cell. This liquid or hydrostatic pressure works against osmosis. Turgidity is very important to plants because this is what make the green parts of the plant "stand up" into the sunlight.

When plant cells are placed in concentrated sugar solutions they lose water by osmosis and they become "flaccid"; this is the exact opposite of "turgid". If you put plant cells into concentrated sugar solutions and look at them under a microscope you would see that the contents of the cells have shrunk and pulled away from the cell wall: they are said to be plasmolysed.

When plant cells are placed in a solution which has exactly the same osmotic strength as the cells they are in a state between turgidity and flaccidity. We call this incipient plasmolysis. "Incipient" means "about to be". When I forget to water the potted plants in my study you will see their leaves droop. Although their cells are not plasmolsysed, they are not turgid and so they do not hold the leaves up into the sunlight.
And now for the

animal cells:

When animal cells are placed in sugar solutions things may be rather different because animal cells do not have cell walls. In very dilute solutions, animal cells swell up and burst: they do not become turgid because there is no cell wall to support the cell membrane. In concentrated solutions, water is sucked out of the cell by osmosis and the cell shrinks. In either case there is a problem. So animal cells must always be bathed in a solution having the same osmotic strength as their cytoplasm. This is one of the reasons why we have kidneys. The exact amount of water and salt removed from our blood by our kidneys is under the control of a part of the brain called the hypothalamus. The process of regulating the amounts of water and mineral salts in the blood is called osmoregulation. My insulin page will tell you more about other homeostatic mechanisms.

Animals which live on dry land must conserve water; so must animals which live in the sea (the sea is very salty!), but animals which live in freshwater have the opposite problem; they must get rid of excess water as fast as it gets into their bodies by osmosis.

Answer 5

Pretend you've got a container and smack bang in the middle there is a piece of plastic carrier bag with lots of microscopic holes in (this is our semi-permeable membrane) one one side of the plastic bag there is pure water, on the other side is salt water.
The water will move from where there is more water molecules (high concentration) to a place where there is less. (low concentration.)

(I'm not trying to patronise you, i just prefer less technical terms sometimes. :))

Good Luck on your science project.

Answer 6

its something about water and a plant i cant really remeber

Answer 7

don't you read your Australian Bible