The Leaf Flashcards
What is the palisade mesophyll?
Top layer of mesophyll
Contains chloroplasts
Long narrow and close together
What is transpiration?
Evaporation of water from plant leaves
What is the cell wall of a phloem and xylem made from?
Xylem is lignin
Phloem is cellulose
What is the upper epidermis ?
Covers the leaf and absorbs light
What is the spongy mesophyll?
Allows co2 and water to enter cells for photosynthesis
What is xylem and phloem made from?
Xylem is dead cells
Phloem is living cells
What is the waxy cuticle?
Waterproof layer to reduce water loss and redirect rainwater into soil so roots can absorb
What are guard cells?
Cells that open and close the stomata depending on water content
What is the stomata?
Pores that allows co2 to absorb into the leaf
What is the lower epidermis?
Bottom layer of leaf with many pores which allows co2 to disuse into leaf
What is translocation?
The movement of sugars through a plant in phloem
Why are there spaces between spongy mesophyll?
To allow diffusion of c02 and water to evaporate
Explain how the palisade tissue layer is adapted to carry out photosynthesis.
It has many chloroplasts to absorb more sunlight or photosynthesis
What are the steps for photosynthesis?
Chlorophyll absorbs sunlight in chloroplast
Water enters plant in root by osmosis and travels to leaves in xylem vessels
Co2 diffuses into leaf through stomata.
Guard cells control stoma size depending on light intensity
Photosynthesis takes place
Light energy converts water and co2 into glucose and oxygen
How is glucose used?
For respiration
To produce fat and storage
To produce amino acids
Describe the transport of water though a plant from the roots to the atmosphere
Water moves through translocation
In xylem cells
Water moves into mesophyll cells
Evaporate
Leave plant via stoma
Explain how and why stomata open in the day and close at night.
In the day, it is light and the guard cells gain water so become turgid, opening the stomata.
This allows carbon dioxide to enter the cell for photosynthesis and oxygen diffuses out.
At night, it is dark, so plants cannot photosynthesise.
The guard cells lose water and become flaccid, closing the stomata.
This prevents excess water loss.
Give 3 differences between xylem and phloem vessels.
Xylem transports water and mineral ions whereas the phloem transports food substances.
Xylem only transports molecules up the plant (one way) but phloem vessels transport molecules all around the plant (moves both ways).
Xylem cells are dead, phloem cells are living.
Xylem cells have no cell walls at the top and bottom to allow substances to pass through
phloem cells have sieve plates between cells to allow substances to pass through.
Give factors that affect the rate of transpiration
Temperature
Wind speed
Humidity
Light intensity
What is the purpose of translocation in plants
Movement of materials from leaves to other areas of the plant
What is the role of stomata and guard cells?
Control gas and water loss
What is the role of meristems?
Trigger growth of new cells
Where are meristems found?
Growing tips
Roots or shoots
Explain how the spongy mesophyll is adapted for its function
Large air spaces to increase surface so carbon dioxide can diffuse into leaf
