Describe the structure of a plant and explain it's functions. (6 marks)

A waxy cuticle is present. This is a waterproof, transparent layer that prevents evaporation of water due to heat from the sun. Because it is transparent, it allows sunlight to pass through to the palisade layer so it can be absorbed by the chlorophyll for photosynthesis to occur. The upper epidermis is also transparent, so the light can pass through this to. The palisade layer contains chloroplasts which has a green substance called chlorophyll, which absorbs sunlight and uses it for photosynthesis to provide energy to the plant. There is a xylem which brings water and nutrients to the leafs for photosynthesis. A phloem transports the dissolved food away to be used by the plant. The lower epidermis has many tiny holes called stomata which are controlled by the guard cells. These prevent water from escaping and also allows carbon dioxide to diffuse in, and oxygen to diffuse out.