B7.1 TRANSPORT Flashcards
Where would you find xylem and phloem tissue in a plant?
In vascular bundles that form veins throughout the roots, stem and leaves.
Describe the structure and function of xylem tissue.
Xylem vessels are long continues tubes formed from dead cells, which allow water and dissolved substances to pass easily through the plant.
Describe the structure and function of phloem tissue.
Phloem cells link together to form continuous phloem tissue in vascular bundles.
They carry dissolved food materials; such as sucrose and amino acids, from the leaves where they are formed to other parts of plant that use the them for life processes or where they will be stored.
Describe the route that water takes as it moves through a plant.
It enters through the root hair cells,»> moves through the root cortical cells to»> xylem in the centre of the root.»_space;> it moves through the xylem up the stem»_space;> and into the leaves.»> In the leaves, it moves out of the xylem into the spongy mesophyll cells.
How could you investigate the above-ground route that water takes as it moves through a plant?
Explain your answer.
Place a stem of a plant in water containing food colouring.
The colour will travel through the xylem with the water, and show where the xylem is in the stem, leaves and flower.
Define the word transpiration.
Evaporation from the surfaces of a plant, particularly from stomata of a leaf into the air.
Explain the advantage to plants of closing their stomata at night in terms of water loss.
Closing stomata reduce diffusion of water molecules out of the leaf.
At night, oxygen is not needed for photosynthesis, so keeping stomata open would lose water unnecessarily.
Explain, in terms of movement of the water molecules, why transpiration rate is faster when temperature is higher
When temperature is higher, particles move faster, so water molecules will diffuse out of the leaf more quickly.
Explain, in terms of movement of the water molecules, why transpiration rate is faster when the humidity of the air is lower.
When air humidity is lower, there is a low concentration of water molecules in the air. So, less water particles will move from air through stomata into and out of the leaf. This means the rate of diffusion will be lower.
