Zusammenfassung der Ressource
Leaves
- Leaves are specially adapted for photosynthesis
- Each component of a leaf has a special function
- Most leaves
- are green- they contain chlorophyll, which absorbs sunlight
- are thin- this allows gases to diffuse in and out of the leaf easily
- have a large surface area- to absorb as much light as possible
- The underneath of the leaf is lighter than the top
- This is because the cells at the bottom of the leaf
contain fewer chloroplasts
- 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
- 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
- Their function is to allow gases to diffuse into and out
of the leaf
- Carbon dioxide diffuses in.Carbon dioxide is a
reactant in photosynthesis
- 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
- Palisade layer- contains cells packed with chloroplasts. This is
where most of a plant's photosynthesis occurs
- spongy layer- contains air spaces, allowing carbon dioxide to
diffuse throughout the leaf. Oxygen diffuses out the leaf