Plant Response

Question 1

Stimulus

Answer 1

Detectable change in environment

Question 2

Tropism

Answer 2

Plant responds to stimulus via growth

Question 3

Positive tropism

Answer 3

Plant grows towards

Question 4

What is tropism controlled by

Answer 4

Growth factors eg IAA

Question 5

What does IAA do

Answer 5

Controls cell elongation in shoots
Inhibits growth in roots

Question 6

Where is IAA made

Answer 6

Tip of the roots and shoots but can diffuse into other cells

Question 7

Phototropism shoots

Answer 7

Light needed LDR photosynthesis
1. Shoot tip produces IAA - cell elongation
2. IAA diffuses to other cells
3. Unilateral light- IAA diffuse towards shaded side
4. Cells on shaded side elongate more plant bends towards light source

Question 8

Phototropism roots

Answer 8

1. Roots don’t photosynthesise
2. Don’t require light
3. Anchor plant deep in soil
4. IAA inhibits cell elongation causing root to elongate lighter side
5. Bends away from light negative phototropism

Question 9

Gavitropism shoots

Answer 9

IAA diffuse uperside to lower side of shoot
If plant shoot vertical, IAA diffuse down causing cells to elongate plant grow upwards
Plant on side = shoot bend upwards negative gravitropism

Question 10

Gravitropsim roots

Answer 10

IAA moves lower side of roots
Upper side elongates
Root bends down towards gravity anchors plant
Positive gravitropism