12.2 - Leaves

Blade - flat part of a leaf

Peticole - attaches the leaf to the stem

function of leaves:

• carry out photosynthesis (needs chlorophyll and chloroplasts)

• gas exchange

• protect the plant (bad taste, toxic, spiky)

cuticle - structure: waxy, function: waterproof, protect, prevent water loss

epidermis - structure: tightly packed cells, transparent, single layer, like tiles, function: allow light to pass, protect (barrier)

palisade mesophyll - structure: cylindrical, full of chloroplasts, function: capture light, photosynthesis

stomata - structure: opening controlled by guard cells, lower epidermis, function: gas exchange, prevent water loss

vascular bundle - structure: made of xylem and phloem, function: transport, venatation (arrangement of veins in leaf)

mesophyll - middle of leaf where things are stored for photosynthesis

human uses of leaves

• food

• tea

• wax of cuticle for cars, surfboards, candy coating, chocolate, lipstick, furniture polish

• construction

• religion

non-toxic leaves and chemicals - can be used to treat cancers and heart disease

toxic leaves and chemicals - rhubarb

psychotropic chemicals/plants - alter the mind, increase appetite, decreases nausea, reduces muscle spasms but can distort perception

coca plants (psychotropic) - when isolated = cocaine, used to be used medicinally (anesthesia), highly addictive, increases alertness and rate of breathing