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
What happens during transpiration
Water travels up the xylem to the leaves
If the stomata are open for photosynthesis the plant will lose water
The water evaporates into the air spaces in the mesophyll layer and diffuses out of the stomata
How are plants adapted to reduce water loss (3)
Stomata is located at the bottom of leaf in the shade
Stomata can open and close
Stomata close in the dark to stop water loss but open in the light for has exchange for photosynthesis
What apparatus is used to measure the rate of transpiration
Potometer
What affects the rate of transpiration (4)
Humidity
Wind speed
Temperature
Light intensity
What happens to the rate of transpiration when humidity increases
Transpiration decreases as the air surrounding the leaves is moist so the concentration gradient is less steep, reducing diffusion
What happens to the rate of transpiration when the wind speeds increase
Transpiration increases as the high wind speeds removes water vapour quickly keeping the concentration gradient steep, increasing diffusion
What happens to the rate of transpiration when temperatures increase
Transpiration increases as the particles have more kinetic energy so evaporation is faster, increasing diffusion
What happens to the rate of diffusion when light intensity increases
Transpiration increases as the stomata opens wider during higher light intensities for gas exchange for photosynthesis. Transpiration also occurs at the stomata so diffusion increases
