In the centre to provide support as it pushes through the soil
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Where are xylem and phloem located in a stem?
towards the outside to provide a 'scaffolding' which reduces bening
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What do xylem and phloem make up in a leaf?
Xylem and phloem make up a network of veins which support thin leaves
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Give one adaptation of xylem vessels...
- They have no end walls which make an uninterrupted tube that allows water to pass up the middle easily.
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Give some more adaptations of xylem vessels....
Their walls are thickened with lignin which provides the walls with support and prevent them collapsing inwards. They also have small pits which allows water and mineral to move into and out of the vessels.
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Do xylem vessels have a cytoplasm?
no because the cells are dead
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What is an adaptation of phloem?
They have sieve tubes which have holes in them to allow solvents to pass through. Also, they have companion cells for every sieve cell due to them not having a nucleus.
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What do companion cells do?
Carry out living functions for themselves and the sieve tubes. E.g- provide energy for active transport of solutes.
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What is the symplast pathway?
It goes through the living parts of the cells (the cytoplasm).
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What is the apoplast pathway?
Goes through the non-living parts (the cell walls). This is because walls absorbent so water can diffuse through them
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When water in the apoplast pathway gets to the endodmeris cells, the path is blocked by a waxy *****. What is this called?
Casparian *****.
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What happens when the water is blocked by this trip?
It has to take the symplast pathway.
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What is transpiration?
When water evaporates from a plants surface
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What is translocation?
Movement of dissolved substances to where they're needed to be.
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