Taxes, Tropism and Kinesis A2

Question 1

define taxes

Answer 1

moving towards or away from a favourable stimulus

Question 2

define kinesis

Answer 2

increase in random movements in unfavourable environments

Question 3

define tropism

Answer 3

growth movement of plants towards or away from a stimulus

Question 4

define hormones

Answer 4

carries by blood
slow
affect different parts of the body
widespread response
long-lasting

Question 5

define chemical mediators

Answer 5

released from mammalian cells
effect cells in the immediate vicinity
spread directly by diffusion

Question 6

what do plants use instead of a nervous system

Answer 6

plant growth factor

Question 7

examples of chemical mediators

Answer 7

histamine, prostaglastins

Question 8

what is plant growth factor

Answer 8

IAA (indoleacetic acid)

Question 9

what does IAA do

Answer 9

causes shoots to grow towards the light and roots towards gravity

Question 10

how does IAA make shoots grow towards the light

Answer 10

IAA made in cells in tip of shoots
transported down shoot on both sides
light causes IAA to move to shaded side of root
stimulates cells on dark side to elongate

Question 11

how does IAA make roots bend towards gravity

Answer 11

IAA made in cells in root tip
moves to lower side of root
inhibits growth on lower side