B3.2.6 Plant Hormones

Question 1

What is a tropism?

Answer 1

Plants detect stimuli in environment and respond by growth in particular direction. (Positive = towards stimuli, negative = away from stimuli)

Question 2

What is a phototropism?

Answer 2

• growing towards light
• when stem grows towards light, plant can photosynthesise more = more food = faster growth = increased chances of survival

Question 3

What is a Gravitropism?

Answer 3

• growing in same direction as gravity

- roots grow downwards = anchorage, closer to water

Question 4

Why are gravitropisms especially important?

Answer 4

When germinating seeds many fall upside down

-enforces plant grows right way up

Question 5

What is auxin?

Answer 5

Plant hormone that enables plant to grow towards or away from stimulus

Question 6

Where is auxin made?

Answer 6

In cells near tips of plant shoots or roots

Question 7

Auxin in shoots and roots

Answer 7

Stimulates shoot to grow more

Inhibits growth of root cell

Question 8

How does auxin respond to light?

Answer 8

When light hits one side of shoot tip, auxin moves to other side (in shade side) and that side grows more on that side, bending towards light