Plant Response

Question 1

Adaptations

Answer 1

Changes in a living organism in order to survive

Question 2

What is plant growth regulated by?

Answer 2

Plant growth is regulated by external and internal factors

Question 3

Name external factors that can affect a plant

Answer 3

Light
Gravity
Temperature
Water

Question 4

What are internal factors that can affect plant growth

Answer 4

Growth regulators

Question 5

Stimulus

Answer 5

Change in environment that caused an reaction in an organism

Question 6

Response

Answer 6

Reaction of an organism to a stimulus

Question 7

Tropism

Answer 7

Growth response of a plant to a stimulus

Question 8

Positive tropism

Answer 8

Growth of plant towards stimulus

Question 9

Negative tropism

Answer 9

Growth of plant away from stimulus

Question 10

Adverse environment

Answer 10

Harsh conditions that can harm a plant

Question 11

Name the 5 types of tropism

Answer 11

Phototropism
Geotropism
Hydrotropism
Thigmotropism
Chemotropism

Question 12

What is phototropism

Answer 12

Growth response of a plant to light

Question 13

What is geotropism

Answer 13

Growth response of a plant to gravity

Question 14

What is chemotropism

Answer 14

Growth response of a plant to chemicals

Question 15

What is hydrotropism

Answer 15

Growth response of a plant to water

Question 16

What is thigmotropism

Answer 16

Growth response of a plant to touch

Question 17

Describe phototropism

Answer 17

Shoot is positively phototropic
Root is negative phototrophic

Question 18

Advantages of phototropism

Answer 18

Shoot absorbs more light- more photosynthesis
Roots anchor the plant into soil

Question 19

Describe geotropism

Answer 19

Shoot negatively geotropic
Root positively geotrophic

Question 20

Describe the advantages of geotropism

Answer 20

Plants anchored in the ground
Allows roots to absorb water and minerals

Question 21

Describe hydrotropism

Answer 21

Root positively hydrotropic
Shoot negatively hydrotropic

Question 22

Describe chemotropism and give an example not involving roots

Answer 22

Roots negatively chemotropism towards acid
Roots positively chemotropic towards minerals
Eg. Pollen tube grows towards chemicals released by ovule

Question 23

Describe thigmotropism

Answer 23

Climbing plants have tendrils - wrap around objects for support (positively thigmotropic)
Roots grow away from stones in soil (negatively thigmotropic)

Question 24

Describe the mechanism of phototropism

Answer 24

IAA is produced in the meristem of the stem tip. When light shines on one side of the plant. IAA diffuses down shady side.Causes cells to grow and elongate on shady side. The plant structure bends over towards light due to the growth differences

Question 25

What is a growth regulator

Answer 25

chemical that controls the growth of a plant

Question 26

Where are plant regulators transported

Answer 26

Vascular tissue

Question 27

List the similarities between animal hormones and plant growth regulators

Answer 27

Produced in small amounts at one site and act in another site Both transported in vascular tissue Slow response time Long lasting effect

Question 28

What are growth promoters

Answer 28

Encourage the growth of plants

Question 29

What are growth inhibitors

Answer 29

Stops/ prevents the growth of plants

Question 30

Name a growth promoter and a growth inhibitor

Answer 30

Growth promoter- Auxins /IAA Growth inhibitor-ethene

Question 31

In the case of a growth inhibitor, name, state where it is produced and its affects

Answer 31

Ethene Produced by stem nodes, ripe fruits and decaying leaves It causes fruit ripen and leaves to fall and decay during autumn

Question 32

Where is IAA/auxins produced

Answer 32

Meristem tissue in the roots and shoot tip

Question 33

Name and briefly explain the affect of auxins

Answer 33

Fruit formation+flower formation Apical dominance ( apical bud is cut so material buds can develop) **Cell division - weakens cell wall causing water to be absorbed, promotes growth** Root and shoot growth

Question 34

Describe the effect of IAA on root and shoot growth

Answer 34

High concentrations of IAA inhibit root growth and encourage shoot growth Low concentrations of IAA inhibit shoot growth and stimulate root growth

Question 35

Name commercial use of growth regulators

Answer 35

Rooting power Ethene ripens fruit Seedless fruits Weed killers (inhibits root growth)

Question 36

Name ways that plants protect themselves against adverse external environment

Answer 36

Spines,thorns, stinging hair to stop being eaten by animals Guard cells shrivel and close stomata: stop excess water loss Stress proteins production: attack by microorganisms

Question 37

Describe the procedure to investigate the effect of different concentrations IAA growth regulator on plant tissue

Answer 37

A serial dilation produced different concentrations of IAA. to ensure it is a fair test, each dish , expect the control, has 9ml of IAA solution diluted to different concentrations. Control dish has only water. Place gridded acetate paper in the Petri dishes and place radish seeds evenly spaced on to the same line.secure using petroleum jelly. Add filter paper and Cotten wool on top Seal and stand on side to ensure the root grows down and shoot grows up. Incubate @ 25C for 3-5 days

Question 38

In investigate the effect of different concentrations IAA growth regulator on plant tissue, what was the plant tissue?

Answer 38

Radish seeds

Question 39

In investigate the effect of different concentrations IAA growth regulator on plant tissue, what is the purpose of the acetate grid paper?

Answer 39

Count length of roots and shoots

Question 40

In investigate the effect of different concentrations IAA growth regulator on plant tissue, what is the purpose of filter paper

Answer 40

Ensure root and shoot do not get tangled in cotton wool

Question 41

In investigate the effect of different concentrations IAA growth regulator on plant tissue, what is the purpose of the cotton wool

Answer 41

soaked up IAA solution

Question 42

Explain the Results In investigate the effect of different concentrations IAA growth regulator on plant tissue

Answer 42

Lengths of roots and shoot measured The results are compared to the control results High conc of IAA stimulated shoot growth ( long shoot). Inhibited root growth Low conc of IAA- stimulate root growth( long root) Inhibited shoot growth ( short shoot) Control- root and shoot grew equal amounts