Stimuli and Responses- Responses in Plants and Animals

Question 1

What do plants do once they sense the direction of light?

Answer 1

They grow towards the light to maximise light absorption for photosynthesis

Question 2

What do plants do once they sense gravity?

Answer 2

Their roots and shoots grow in the right direction

Question 3

Why do climbing plants have a sense of touch?

Answer 3

So they can find things to climb up and reach the sunlight

Question 4

What is a tropism?

Answer 4

The response of a plant to a directional stimulus

Question 5

How do plants respond to stimuli?

Answer 5

By regulating their growth

Question 6

What is a positive tropism?

Answer 6

Growth towards the stimulus

Question 7

What is a negative tropism?

Answer 7

Growth away from the stimulus

Question 8

What is phototropism?

Answer 8

The growth of a plant in response to light

Question 9

What are shoots in regards to phototropism?

Answer 9

They are positively phototropic and grow towards light

Question 10

What are roots in regards to phototropism?

Answer 10

They are negatively phototropic and grow away from light

Question 11

What is gravitropism?

Answer 11

The growth of a plant in response to gravity

Question 12

What are shoots in regards to gravitropism?

Answer 12

Negatively gravitropic and grow upwards

Question 13

What are roots in regards to gravitropism?

Answer 13

Positively gravitropic and grow downwards

Question 14

How do plants respond to directional stimuli?

Answer 14

Using specific growth factors

Question 15

What are growth factors?

Answer 15

Hormone-like chemicals that speed up or slow down plant growth

Question 16

Where are growth factors produced and where do they move to?

Answer 16

They are produced in the growing regions of the plant and move to where they’re needed in the other parts of the plant

Question 17

What are auxins?

Answer 17

Growth factors that stimulate the growth of shoots by cell elongation

Question 18

What happens if there are high concentrations of auxins?

Answer 18

They inhibit growth in roots

Question 19

What is indoleacetic acid (IAA)?

Answer 19

An important auxin that’s produced in the tips of shoots in flowering plants

Question 20

Why is IAA moved around the plant?

Answer 20

To control tropisms

Question 21

How is IAA moved around the plant?

Answer 21

By diffusion and active transport over short distances, and via the phloem over long distances

Question 22

What are tactic responses (taxes)?

Answer 22

The organisms move towards or away from a directional stimulus

Question 23

What are kinetic responses (kineses)?

Answer 23

The organisms’ movement is affected by a non-directional stimulus