What is the waxy cuticle?
A thin, waterproof layer on top of the leaf that reduces water loss.
Why is the waxy cuticle important?
It stops the leaf drying out.
What is the upper epidermis?
A transparent layer of cells on the top of the leaf.
Why is the upper epidermis transparent?
To let light through to the palisade cells for photosynthesis.
What is the palisade mesophyll?
A layer of tall, tightly packed cells full of chloroplasts.
What is the function of the palisade mesophyll?
To absorb lots of light for photosynthesis.
Why does the palisade mesophyll have many chloroplasts?
To capture as much sunlight as possible.
What is the spongy mesophyll?
A layer of cells with air spaces between them.
What is the function of the spongy mesophyll?
To allow gases like CO₂ and O₂ to move easily through the leaf.
Why does the spongy mesophyll have air spaces?
To help gases diffuse quickly.
What is the xylem?
A tube that carries water and minerals from the roots to the leaf.
What is the function of the xylem in the leaf?
To supply water for photosynthesis and keep the leaf turgid.
What is the phloem?
A tube that carries sugars made in photosynthesis around the plant.
What is the function of the phloem?
To transport glucose to the rest of the plant for energy and growth.
What is the lower epidermis?
The bottom layer of the leaf that contains most of the stomata.
What are stomata?
Tiny pores in the leaf that let gases in and out.
What gas enters the leaf through stomata?
Carbon dioxide.
What gas leaves the leaf through stomata?
Oxygen (and water vapour).
What are guard cells?
Cells that open and close the stomata.
Why do guard cells close stomata?
To reduce water loss when the plant is drying out.
