plant hormones (paper 2)

Question 1

stimulus definition

Answer 1

change in the environment

Question 2

list 3 stimuli for plants to grow

Answer 2

light
gravity
water

Question 3

3 reasons why plants need to respond to their environment

Answer 3

avoid stress e.g. lack of light
increase growth rate
improve chances of successful breeding

Question 4

3 main types of plant growth

Answer 4

cell division
cell elongation
cell differentiation

Question 5

which way do shoots grow

Answer 5

above ground

Question 6

which way do roots grow

Answer 6

below ground

Question 7

which way do tips grow

Answer 7

downwards to light

Question 8

plants produce hormones to coordinate and control… (2)

Answer 8

growth and responses to light
growth responses to gravity

Question 9

what does ethene control?

Answer 9

cell division and ripening of fruits

Question 10

list 2 ways geotropism allows plants to increase their chances of survival

Answer 10

• ensuring plant is upright to obtain light for photosynthesis
• encouraging deeper roots to anchor the plant

Question 11

auxin function

Answer 11

plant hormone responsible form controlling the direction of growth of root tips and shoot tips in response to different stimuli including light and gravity

Question 12

positive phototropism

Answer 12

moving towards light

Question 13

negative phototropism

Answer 13

moving away from light

Question 14

where is auxin made

Answer 14

tips of stems and roots

Question 15

explain how in shoot tips light and gravity interfere with the transport of auxin, causing it to be unevenly distributed (5)

Answer 15

• auxin produced in shoot tips
• auxin diffuses to shaded side
• concentration of auxin on shaded size increases
• higher concentration of auxin causes cells on shaded side to increase their length
• causes shoot tip to bend forwards to the light i.e. shoot tips show positive phototropism

Question 16

positive phototropism part of plant and direction of growth

Answer 16

stem tip
growth towards light

Question 17

negative phototropism part of plant and direction of growth

Answer 17

root tip
growth away from light

Question 18

positive gravitropism part of plant and direction of growth

Answer 18

root tip
growth towards gravity

Question 19

negative gravitropism part of plant and direction of growth

Answer 19

stem tip
growth away from gravity

Question 20

4 ways plant hormones can be used

Answer 20

growth cuttings
ripening fruit
killing weeds
tissue culturing

Question 21

define a cutting

Answer 21

part of a plant that is removed from the main shoot

Question 22

tissue defintion

Answer 22

group of cells with similar structure that works together to carry out a specific function

Question 23

2 ways in which auxins are used

Answer 23

weed killers
rooting powders
promoting growth in tissue culture

Question 24

what do weed killers do

Answer 24

very high doses can cause plants to grow too quickly and die

Question 25

what do rooting powders do

Answer 25

encourage meristem in cuttings to grow into new roots

Question 26

give one use for ethene

Answer 26

used in food industry to control ripening of fruit during storage and transport

Question 27

what is a growth movement to a stimulus called?

Answer 27

tropism

Question 28

shoot tips grow… sunlight. They are…

Answer 28

towards
positively phototrophic

Question 29

shoot tips grow away from… . They are…

Answer 29

gravity
negatively geotropic

Question 30

root tips grow away from… . They are…

Answer 30

sunlight
negatively phototrophic

Question 31

root tips grow towards… . They are…

Answer 31

gravity
positively gravitropic

Question 32

a young plant is laid on its side. Describe the distribution of auxin in the root an the shoot

Answer 32

auxin accumulates on both sides making it uneven

Question 33

explain how the auxin affects the growth of the root and the shoot

Answer 33

cells elongate faster on the side with less auxins causing shoot to bend downwards in the direction of force of gravity

Question 34

which hormone controls cell division plants?

Answer 34

ethene

Question 35

give three uses of gibberellins in horticulture

Answer 35

promote flowering
increase fruit size
end seed dormancy

Question 36

suggest why bananas destined for UK supermarkets are picked before they are ripe? (2)

Answer 36

fruit is firmer so it is less easily damaged meaning it can then be ripened on the way to the supermarket