Plant Organisation Flashcards
(32 cards)
What is the main role of plant stems and roots? - Transport
For transporting substances throughout the plant
What do xylem tissues transport? - Transport
Water + mineral ions
What do phloem tissues transport? - Transport
Sugars and proteins dissolved in water
Name 2 ways plant leaves are adapted for photosynthesis - Plants
Large surface area - provides max absorption of light + CO2
Air spaces between cells - allows easier diffusion of gases
How is the palisade mesophyll adapted to absorb light? - Plants
Packed with chloroplasts
Cells arranged closely together
Towards the leaf’s upper surface to increase exposure to light
How is the spongy mesophyll adapted for gas exchange? - Plants
Loosely packed to increase space for gaseous exchange
Which direction do xylem transport substances? - Plants
Upwards
How are xylem tissues specialised? - Plants
They have no end walls, meaning there is a continuous stream of transport
Strengthened by a chemical called lignin, meaning the plant had support
Which direction do phloem tissues move substances? - Plants
Upwards and downwards
What is the movement of substances in phloem tissues called? - Plants
Translocation
Does the movement of substances in phloem cells require energy? - Plants
Yes, it’s done by active transport
Does the movement of substances in xylem cells require energy? - Plants
No, it is done by diffusion
What is transpiration? - Plants
The loss of water from plant leaves by evaporation through an open stomata
How is water lost through transpiration replaced? - Plants
Water is drawn from xylem cells to replace lost water
Name 3 purposes of water for plants - Plants
Used as water for photosynthesis
Transports mineral ions
Keeps the cell turgid
Cools the leaf as water evaporates
How does water enter root hair cells (through what process?) - Plants
Osmosis
What is the purpose of root hair cells? - Plants
To absorb water and mineral ions from the soil
How does temperature affect the rate of transpiration? - Plants
Temperature increases the rate of transpiration as it increases the rate of evaporation from cell surfaces. Rate of diffusion is increased
How does humidity affect the rate of transpiration? - Plants
Humidity decreases the rate of transpiration as it reduces the concentration of water molecules outside the leaf, meaning rate of diffusion from leaf increases
How does air movement affect transpiration? - Plants
Increases the rate of transpiration as it removes water vapour from leaf surfaces, meaning more water diffuses from the leaf
How does light intensity affect transpiration? - Plants
An increase of LI increases transpiration as it increases the rate of photosynthesis, meaning the stomata is open and water diffuses from the leaf
How can you measure the rate of transpiration with a simple method? - Plants
Measure the mass of leaves before changing temperatures, suspend them under new temperature and then after a set period of time remeasure the mass
What can potometers be used to measure? - Plants
The uptake of water by a plant’s roots
How can potometers be used? - Plants
Fill a potometer with water, placing it and a woody plant under water to ensure its xylem is full of water. Insert the plant into the potometer. Measure how an air bubble moves up the potometer over time
