Gas exchange in the leaf of a plant

Waxy cuticle:

• Transparent layer on top of the leaf
• Waxy
• Waterproof

Upper epidermis:

• Single layer of flat cells covering the top surface of the leaf
• no chloroplasts

Paliside cells:

• Layer of long cylindrical cells just under the upper epidermis
• Chloroplasts
• Chlorophyll

Chloroplast:

• Small structures within the cell where photosynthesis takes place

Spongy mesophyll:

• Layer of cells with air-spaces between them

Vein:

• Contains the tissues that transport food and water
• Xylem - carries water through the plant
• Phloem - carries food through the plant

Lower epidermis:

• Single layer of flat cells covering the bottom surface of the leaf

Guard cells:

• Control the closing and opening of the stomatal pores

Stoma:

• Pores on the underside of the leaf
• Stomata = holes
• Close at time where water loss would be excessive

Internal structure of a leaf:

• The cuticle is a waxy layer on the surface that prevents water from evaporating from the leaf
• Most photosynthesis occurs in the chloroplasts that are tightly packed inside the paliside cells
• During photosynthesis, the gas C02 and water and combined together…