Leaf Structure

Question 1

Upper epidermis

Answer 1

The upper epidermis is one cell thick and covers the leaf like skin. The cuticle is a waxy layer which protects the leaf against disease organisms such as parasitic fungi

Question 2

Palisade mesophyll layer

Answer 2

Palisade cells have a cylindrical shape. This helps the light to penetrate into the leaf.
Chlorophyll is contained in chloroplasts. Palisade cells have the more chloroplasts than other cells in the leaf.

Question 3

Spongy mesophyll layer

Answer 3

This layer consists of irregularly shaped cells with large air spaces between them and looks like a sponge when seen under a microscope. The cells have fewer chloroplasts than the palisade cells since the light intensity is less

Question 4

Guard cells

Answer 4

Stomata open and close in response to changing conditions such as light intensity, humidity and carbon dioxide concentration

Question 5

Leaf vein

Answer 5

Water and salts enter the leaf via the xylem. Sugar made by photosynthesis passes out of the leaf via the phloem

Question 6

Lower epidermis

Answer 6

The lower epidermis is a layer one cell thick, like the upper epidermis. It contains pores called stomata (singular stoma). Each stoma is made up of a pair of guard cells.