Exam Questions

Question 1

Explain why plants need to be able to respond to their environment

Answer 1

-to cope with changing conditions
-to obtain more light

Question 2

State 2 commercial uses of plant growth substances

Answer 2

-weed killers
-control ripening of fruit

Question 3

Describe 2 ways in which hormones may alter a plant growth in response to overcrowding by other plants

Answer 3

-auxin
-plants and shoots bend towards light
-plants grow taller

Question 4

Suggest how hormones alter the growth and morphology, or growth, and development of a plant

Answer 4

-auxins - apical dominance
-gibberellins - germination
-ethylene - ripening

Question 5

Explain why plant hormone is a more accurate term that plant growth regulator

Answer 5

-not all plant hormones are responsible for plant growth
-hormones are chemical messengers
-role in the cell is communication
-respond to target cells with a range of long term effects

Question 6

Explain why gibberellin is classed as a plant hormone

Answer 6

-acts as a chemical messenger
-produced in one part of plant but has effects in another part
-has long lasting effects

Question 7

State one example of a response that plants use against herbivory

Answer 7

-folding in response to touch

Question 8

What is the plant hormone responsible for stomatal closure?

Answer 8

-ABA

Question 9

What are the chemicals produced by a plant that acts like a pheromone?

Answer 9

-volatile organic compounds

Question 10

Explain why plants need to be able to respond to their environment

Answer 10

-to maximise photosynthesis
-to cope with changing conditions

Question 11

State 2 commercial uses of plant substances

Answer 11

-weed killers
-control fruit ripening

Question 12

How is cross seedling growth affected by overcrowding?

Answer 12

-fight for light
-need light for positive phototropism
-plants will then bend towards the light

Question 13

How is the growth of a low hawthorn hedge affected by grazing by goats?

Answer 13

-less auxin available
-apical dominance is stopped
-side shoots will start to grow

Question 14

How is asparagus growth affect by covering the young shoots with an upturned box to exclude light?

Answer 14

-by auxins which aren’t destroyed by light
-cells elongation occurs

Question 15

Explain experimentally how a student could determine which bottle contains auxins and the other containing gibberellin

Answer 15

-apply solutions separately to cut stems
-run a control group with no chemical
-dependent variable = height
-control = same age, mass, soil and light
-auxin = curving of stem toward the light
-gibberellin = straight growth of stem