B4a Who planted that there

Leaves have the

• Same basic structure
• Carry out photosynthesis
• Chlorophyll - green pigment - traps sunlight produces food
• Leaf colour varies - Cholorophyll breaks down, lets other pigments through

Adapted for photosynthesis by;

• Broad surface area- more exposed to light
• Thin - carbon dioxide and water vapour only have to travel a short distance to the photosynthesing cells.
• air spaces in spongy mesophyll layer- allows gases like Carbon dioxide & oxygen to move easily between cells.

          - this also means large surface for gas exchange - "they have a very big internal surface area to volume ratio"

Carbon Dioxide+water = Glucose+Oxygen

6CO2+6H2O = C6H12O6+6O2

where does it get it

carbon dioxide from the air

Water from soil

What does it use it for

Glucose for respiration and coverted into storage or use in cell

Oxygen released in to the air or used in respiration

structure of a leaf Leaves are designed for making food by photosynthesis.

• Chlorophyll - the pigment that absorbs light for photosynthesis. Found in Chloroplasts, most of which found in palisade layer. near the top so get most light.
• Upper epidermis - transparent so light can pass through to palisade layer.
• lower surface have lots of stomata, which let gases in and out. Also lets water escape - Transpiration
• Veins - deliver water and other nutrients to every part of leaf and take away food produced by leaf.also supports the structure.
• No cells in cuticle, wax layer, prevents water loss.
• Stomata gas diffuses in and out of lower epidermis

Palisade mesophyll - near top-contains the most chloroplasts to trap light energy and photosynthesise

Air spaces in the spongy mesophyll - allows diffusion of gases between the stomata and the photosynthesising cells in the mesophyll layers

Very large internal surface area - for more absorbtion of carbon dioxide

Guard cells - controls opening and closing of the stomata for entry and release of gases