Chemical influences on animal growth
Lead poisoning Inhibits the action of some enzyme, e.g. catalase Reduces plant growth Causes learning difficulties in young children Sources include petrol and lead piping
First symptoms of lead poisoning: vomiting, clumsiness, irritability and headaches. pacific/ stm pacific/ stm h_and_east/ stm h_and_east/ stm
Iron Component of : - haemoglobin - many enzymes and cytochrome Shortage leads to anemia
Iron deficiency
Calcium Obtained from milk products Component of shells, bones and teeth Needed for blood clotting
Vitamin D Obtained from milk Formed in the skin when exposed to sunlight Promotes the absorption of calcium from the intestine Required fro bone formation Shortage leads to deformed bones in young children (rickets)
Rickets (Vitamin D deficiency)
Rickets (Vitamin D deficiency)
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Drugs Many drugs taken during pregnancy can pass across the placenta and affect the foetus -Thalidomide: anti-nausea drug, causes limb deformities
Drugs Many drugs taken during pregnancy can pass across the placenta and affect the foetus -Thalidomide: anti-nausea drug, causes limb deformities Alcohol: may retard growth and mental development. In extreme cases, foetal alcohol syndrome develops
Drugs Many drugs taken during pregnancy can pass across the placenta and affect the foetus -Thalidomide: anti-nausea drug, causes limb deformities Alcohol: may retard growth and mental development. In extreme cases, foetal alcohol syndrome develops Nicotine: may retard growth and mental development