IAA

Question 1

what is auxin (IAA)

Answer 1

a plant grown chemical produced in a plant in low concentration then transported to where they are needed.

Question 2

how does auxin cause a cell to grow differently in different lights

Answer 2

auxin is actively transported away from the side where the light is coming from causing cell elongation in the cells on the dark side causing the plant to grow towards the light

Question 3

effect of IAA on transcription

Answer 3

1. IAA binds to a cell surface membrane receptor and enters the cell and moves to the nucleus
2. IAA binds to a transcription factor and so switches on the gene
3. RNA polymerase binds to the promoter region and mRNA in made in transcription
4. mRNA is then translated to make a specific protein

Question 4

how does IAA cause cell elongation in plants

Answer 4

1. IAA switches on a gene and causes acidification of the cell wall by causing excess pumping of H+ from out of the cytoplasm and into the cell wall
2. the H+ causes a reduction in pH which activates enzymes in the cell wall to break the bonds between cellulose and microfibrils allowing the cell wall to expand
3. uptake of hydrogen ions into the cell wall from the cytoplasm causes water molecules to follow by osmosis so the cell can now swell and elongate.