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HORMONES Where do they come from ? How do they travel ? Where are they broken down ? What does adrenaline do? What are the differences between nervous and hormonal control?. Tropism Objective: To know how plants respond to different stimuli. Key words:
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HORMONES Where do they come from? How do theytravel? Where are theybrokendown? Whatdoesadrenaline do? What are thedifferencesbetweennervous and hormonal control?
Tropism Objective: To know how plants respond to different stimuli
Key words: Tropism: responding to a stimulus by growing towards it or away from it. Phototropism: A tropism caused by light Auxins: Plant hormones
Plants respond to stimuli in the environment just as humans do. This helps them to survive. The shoots and leaves of a plant will follow the sun during the day, this is called phototropism. This allows them to make plenty of food.
Auxins are hormones that control how plants respond to sunlight. They make the cells on one side of the plant grow longer so that the shoot bends towards the light
What are auxins? Whereisitmade? Whatdoesit do? Howisitbrokendown? Howdoes light affectwhereauxins are ontheplant? Whatistheeffect of thisauxindistribution in response to light? Define “phototropism” Whatotherstimuls do plantsrespondto? How can plant hormones be usedbyplantgrowers and scientists? Can you think of anexperimenttoinvestigateauxins and phototropism? PAGE 154, 155 “auxin and tropism”
MUST HAVE PLANT HORMONE INFO: • Phototropismisgrowth in response to light, towards light. • Geotropismisgrowthtowardsorawayfromtogravity. • Tropism is controlled by auxins. • Auxins regulate differential growth(enhanced growth in certain parts of the plant)
USE TO HUMANS • We can sythesise a hormone whichinhibitsplantauxin. • Can you thinkhowthiswould be useful? • Synthetic hormones can block auxins. Thisstops a plantgrowing. Thisisused as aneffectiveweedkiller.