Plants

Question 1

Define tropism

Answer 1

Growth movement in response to stimulus

Question 2

Describe negative tropism

Answer 2

Growing away from stimulus

Question 3

Describe positive tropism

Answer 3

Towards stimulus

Question 4

Describe negative phototropism

Answer 4

Growth away from light

Question 5

Describe geotropism

Answer 5

Growth away from light

Question 6

Auxin function

Answer 6

Promotes growth

Question 7

Causes of tropisms

Answer 7

• sunlight breaks down auxin
• area of plant with shade= auxin accumulates
• more growth on shaded side
  = lop sided growth

Question 8

Why do plants compete

Answer 8

• light and water
• nutrients
• space

Question 9

Define phototropism

Answer 9

Shoots growing towards the light

Question 10

Where is auxin produced

Answer 10

The tips of the plant

Question 11

Describe how auxin works

Answer 11

• light causes auxin to concentrate on the darker side of the shoot tip
• auxin now spreads down the shoot
• cells on darker side grow faster than cells in lighter side
  = causes shoot to grow towards light

Question 12

Define geotropism

Answer 12

Plants growing towards gravity
(Downwards)

Question 13

Describe how geotropism works

Answer 13

• auxin produced at the root
  But
• gravity causes auxin to concentrate on lower side
  = lower side grows more slowly than upper side

Question 14

Use of giberellins

Answer 14

Starting the germination of seeds

Question 15

Use of ethene

Answer 15

Controls cell division and the ripening of fruits

Question 16

Uses of auxins in farming etc

Answer 16

• weed killers
• rooting powders
• promoting growth in tissue culture

Question 17

Uses of giberellins in farming etc

Answer 17

• end seed dormancy
• encourage plants to flower
• grow larger fruit

Question 18

Use of ethene eg farming

Answer 18

• tigger bananas to ripen just before they are sold in the UK

Question 19

Function of fertilisers

Answer 19

Increase growth and reproduction of algae
= more food for plants
= higher plant population

Question 20

Use of auxin in roots

Answer 20

Inhibits cell growth
= lower side grows slower than upper side
= cause roots to grow towards force of gravity