Water potential

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  • Created by: exam yes
  • Created on: 16-01-19 21:46
What is the value of pure water potential and how is it reached?
Pure water has a potential of zero and is reached by the sum of other water potentials such as matric, solute and pressure potential
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How is solute and pressure potential linked?
Links by the different states of plant cells such as turgid and plasmolysed cells.
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How do plant cells become turgid and what is the pressure? (detailed)
Turgid cells are under positive pressure where water moves into the vacuole down a potential gradient, this is due to solutes inside the cell creating a more negative water potential than outside the cell.
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In comparison, what is a plasmolysed cell and what is the pressure?
A plasmolysed cell has negative pressure where there is a lack of water inside the cell and it becomes flacid where the cytoplasm pulls away from the membrane.
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Which water potetnial needs to first be considered with water movemet into and up a plant?
The matric potetial needs to first be considered.
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What is the potentials of the soil and root cells in order for water to move in?
The soil has a negative matric potential and so the root cells need an even lower water potential than this for water to move into the roots
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How does water reach the top of a tree?
By transpiration on te surface of leaves where water moves throught he xylem of the plant by chains of water molecues being pulled upwards as others exit at the leaves.
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How is water potetial involved in the movement of water up a plant and transpiration? - what property does water have that allows this?
There is a lower water potential in the atmosphere compared o inside the leaves and so water molecules diffuse out the plant pulling others with it due to their cohesive properties
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How can types of pressurised cells control transpiration? (not detailed)
Due to guard cells located at the stomata on leaves where gases diffuse through changing their state.
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How do guard cells cause stomata to open and close?
Turgid guard cells cause the stomata to open (positive pressure) and so allowing transpiration to occur. When the cells are under negative pressure and are plasmolysed the stomata close.
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Why do plasmolysed guard cells cause stomatat to close? (in helping the plant)
It is to reduce water loss in order to restore the plant cells and eventually return them to a turgid state
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Other cards in this set

Card 2

Front

How is solute and pressure potential linked?

Back

Links by the different states of plant cells such as turgid and plasmolysed cells.

Card 3

Front

How do plant cells become turgid and what is the pressure? (detailed)

Back

Preview of the front of card 3

Card 4

Front

In comparison, what is a plasmolysed cell and what is the pressure?

Back

Preview of the front of card 4

Card 5

Front

Which water potetnial needs to first be considered with water movemet into and up a plant?

Back

Preview of the front of card 5
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