Changing the way you learn

Leaves

Leaves are specially adapted for photosynthesis
1. Each component of a leaf has a special function
Most leaves
1. are green- they contain chlorophyll, which absorbs sunlight
2. are thin- this allows gases to diffuse in and out of the leaf easily
3. have a large surface area- to absorb as much light as possible
The underneath of the leaf is lighter than the top
1. This is because the cells at the bottom of the leaf contain fewer chloroplasts
2. Most sunlight hits the top of the leaf so this is where the chloroplasts need to be to absorb as much light as possible
The top of the leaf feels waxy
1. The waxy layer reduces the amount of water evaporating out of the leaf
The tiny holes at the bottom of the leaf are called stomata
1. Their function is to allow gases to diffuse into and out of the leaf
  1. Carbon dioxide diffuses in.Carbon dioxide is a reactant in photosynthesis
  2. Oxygen and water vapour diffuses out. Oxygen and water are products of photosynthesis
Stomata are opened and closed by guard cells. These cells open the stomata during the day, and close them at night
The leaf is divided into two layers
1. Palisade layer- contains cells packed with chloroplasts. This is where most of a plant's photosynthesis occurs
2. spongy layer- contains air spaces, allowing carbon dioxide to diffuse throughout the leaf. Oxygen diffuses out the leaf

Leaves

	Created by alex.patterson about 8 years ago