Plant hormones (paper 2) TOPIC 5

Question 1

what do plants need to grow well

Answer 1

• carbon dioxide
• sunlight
• water
• mineral ions

Question 2

does the way a seed lands on the soil impact the growth

Answer 2

no

Question 3

which way do roots grown

Answer 3

they grow down into the soil, anchoring the seedling and keeping it stable

Question 4

why do roots grow down

Answer 4

because they are sensitive to gravity

Question 5

what are plant growth responses called

Answer 5

tropsims

Question 6

what are tropisms

Answer 6

tge responses if plant shoots and roots to light and gravity

Question 7

what is phototropism

Answer 7

growth and responses to light

Question 8

what is gravitropism/geotropism

Answer 8

growth reponses to gravity

Question 9

what are the useful plant hormones

Answer 9

• auxin
• gibberellins
• ethene

Question 10

what does unequal distributions of auxin cause

Answer 10

make one side of a shoot or root grow longer than the other, causing it to bend

Question 11

what does auxin do

Answer 11

controls the direction of growth of root tips and shoot tips in response to different stimuli including light and gravity

Question 12

where is auxin made

Answer 12

at the tips of stems and roots, diffusing along the shoot or roots

Question 13

what will happen to auxin if light is coming in from one side

Answer 13

it will move to the opposite side of the shoot causing the cell to elongate on the one side and bend

Question 14

what is the effect of high levels of auxin

Answer 14

it makes the shoot cells grow more but inhibit growth of root cells

Question 15

does auxin move away or towards light

Answer 15

away

Question 16

what effect does auxin have in the roots

Answer 16

the sides with less auxin will elongate faster

Question 17

what effect does auxin have in the shoots

Answer 17

the sides with more auxin elongate faster

Question 18

how do light and gravity interfer with the transport of auxin

Answer 18

they make it unevenly distributed

Question 19

what is positive phototropism

Answer 19

when the stem tip grows towards light to get maximum light for photosynthesis

Question 20

what is negative phototropism

Answer 20

when the root top grows away from light for less chance of drying out

Question 21

what is positive gravitropism

Answer 21

when the root tip grows towards gravity for more chance of finding moisture

Question 22

what is negative gravistropism

Answer 22

when the stem tip grows away from gravity for more chance of finding light

Question 23

what else are plant growth hormones used in

Answer 23

• agriculture
• horticulture

Question 24

how else is auxin used

Answer 24

• weed killer
• rooting powders
• growth in tissue culture

Question 25

how is auxin used in weed killer

Answer 25

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

Question 26

how is auxin used as rooting powders

Answer 26

they encourage meristem in cuttings to grow new roots

Question 27

explain how ethene is used in the food industry

Answer 27

to control ripening of fruit during storage and transport
- unripe fruit can be picked and transported
- the fruit can be ripened with ethene at its destination

Question 28

what can gibberellins be used to do

Answer 28

• end seed dormancy
• promote flowering
• increase fruit size

Question 29

what do gibberellins do in the plant

Answer 29

initiate seed germination

Question 30

what does ethene do in the plant

Answer 30

controls cell division and ripening of fruits