Vacuole

[Sinead Ryan]

Why does an animal cell contain a contractile vacuole and a plant cell contains a non-contactile vacuole???

[Poison]

correct me if im wrong. Animal cells do not have cell wall. And can burst if too much water entrance occurs. But in plant cells there is cell wall and gives the cell strength.

[Sinead Ryan]

so by using the micro fibres to contract the vacuole to rid the cell of water they vacuole prevents the cell from bursting??? how then does a vacuole in a plant cell ged rid of excess water??

[MrMistery]

first of all, both plant and animal cells contain non-contractile vacuoles. They are the way cells store certain stuff(like glucose in the orange fruit). The contractile vacuola is just a certain type of vacuola.
Now, how does the plant get rid of exces water. There are 2 ways:the most important is perspiration-eliminating water under the form of vapors. At night, when there is no prespiration the plant eliminates water under the form of drops. Both proceses take place mostly in leaves, but not only there. It is said that 99% of the water absorbed through the root is then lost through one of these processes.
Hope this helpes

[mith]

@MrMistery
I believe he was referring to the cell and not the whole plant.

[MrMistery]

Yeap, u r right. Sorry, i didn't c that because i was very tired.
From what i know the process is simple. The vacuole reaches the membrane through the cytoplasmatic curents and then joines it's membrane with the celular membrane, thus eliminating it's content on the outside. the liquit still has to cross the celular wall. This not does usually happen, but not never. Sometimes, the cellular wall is fractured, also even through an unfractured wall water can pass(very hard and very slowly).
I am not sure of this process, plants aren't really my thing. Please correct me if I am wrong.
PS: not all vacuoles eliminate their content. Some are for permanent storage

[mith]

sounds like exocytosis, verification anyone?

[thank.darwin]

What sounds like exocytosis? Water crossing the cell membrane isn't exocytosis.

[mith]

according to MrMistery, the whole vacuole goes and joins with the cell membrane and part of it disappears to release the water.

[Nick]

Isn't the movement of water over a membrane known as Diffusion?

[Rainman600]

so by using the micro fibres to contract the vacuole to rid the cell of water they vacuole prevents the cell from bursting??? how then does a vacuole in a plant cell ged rid of excess water??

there is no excess water in plant cells becuase the cell walls exert equal pressure on the cell membrane - causing osmosis to stop. This condition is called turgid.

[Poison]

Isn't the movement of water over a membrane known as Diffusion?

It is called Osmosis.