Survival

Question 1

Phototropism in stems

Answer 1

Shoot tip produces IAA
IAA diffuses down the stem equally
Light causes IAA to move away from the light to the shaded side IAA causes cells to elongate on the shaded side
Cells on the shaded side grow longer
The stem grows towards the light

Question 2

Gravitropism in roots

Answer 2

Root tip produces IAA
Gravity causes IAA to concentrate in the lower side of the root
IAA inhibits elongation of cells on lower side
Root grows downwards/towards gravity

Question 3

Kinesis

Answer 3

Response to a changing stimulus
Movement is random/not directional
Rate of turning changes

Question 4

Taxis

Answer 4

Directional response to a directional stimulus
Animal moves towards or away from the stimulus