3.6.1.1 response to stimuli

Question 1

taxes

Answer 1

directional movement determined by the direction of the stimulus

Question 2

kinesis

Answer 2

changing speed and turning frequency based on the favourability of the environment

Question 3

what happens to turning frequency in different environments

Answer 3

increased turning - unfavourable environment
decreased turning - favourable environment

Question 4

tropism

Answer 4

growth in a direction due to a stimulus

Question 5

phototropism

Answer 5

growth in response to lights
positive phototropism in shoots
negative phototropism in roots

Question 6

gravitropism

Answer 6

growth in response to gravity
positive gravitropism in roots
negative gravitropism in shoots

Question 7

what are plant growth factors and where are they produced

Answer 7

chemicals that regulate plant growth in response to a stimulus. IAA a type of auxin is produced in the meristem in the tip of roots and shoots

Question 8

shoots showing positive gravitropism

Answer 8

IAA in the meristem in the tip of the shoots diffuse down from the tip to the shaded side.
IAA will increases cell elongation of the shaded side.
causing the shoot to bend towards the light

Question 9

shoots showing negative gravitropism

Answer 9

IAA will diffuse to the underside of the shoot, increasing cell elongation, causing the shoot to grow upwards

Question 10

roots showing negative phototropism

Answer 10

IAA produced in the meristem of the tip of the root will diffuse to the shaded side. IAA in roots inhibit cell elongation. the cells on the non-shaded side will elongate more than the underside curving down away from the light

Question 11

roots showing positive gravtropism

Answer 11

IAA will diffuse to the underside of the root, inhibiting cell elongation, the upperside will elongate more and grow downwards