Plant Transport Flashcards
What is osmosis
The movement of water molecules from a high concentration to a low concentration through a partially permeable membrane
What does the xylem do
Transports water and minerals up the stem
What does the phloem do
Transports sucrose and amino acids up and down the stem
Where is the xylem located
In the inside of the vascular bundles
Where is the phloem located
At the outside of the vascular bundles
Transpiration
The movement of water up a plant from the roots through the stem and out of the leaves
How does a cell become turgid
Water moves from a high concentration outside the cell to a lower concentration inside the cell by osmosis. The cell is turgid
Why do plant cells need to be turgid
The vacuole or cytoplasm will swell and push the cell membrane against the cell wall so the plant is supported. The tutor pressure keeps the cell turgid
How does a cell become flaccid
Water moves from a high concentration inside the cell to a low concentration outside the cell by osmosis. The cell is flaccid
Why are flaccid cells bad
When the vacuole shrinks and the pressure on the cell wall decreases the plant will not be supported and will wilt.
The cell membrane and cytoplasm will detach from the cell wall and the cell will lose its shape and become plasmolysed.
How do plants uptake water and what increases the osmosis
Water is absorbed into the roots by osmosis as there is a high concentration of minerals in the root cells so there is a lower water concentration compared to the soil.
Out layer cells of roots are called root hair cells which have a large surface area
Why do large multicellular organisms need a transport system
They have a small surface area to volume ratio so need a transport system to supply all the cells with what they need
What are the transport systems of a plant and what do they do
Xylem and phloem
Xylem transports water and minerals
Phloem transports sugar and amino acids
What is the structure of a xylem
Made from dead cells stacked on top of each other
to form vessels with hollow lumen
thick cell walls which contain lignin which makes them strong and waterproof.
What is the structure of a phloem
Made from living cells with sieve ends which allows them to be stacked
Forms sieve tubes
Controlled by living cells alongside called companion cells
