Plant Responses to the Environment

Question 1

What are abiotic components?

Answer 1

Components of an ecosystem which are non-living

Question 2

What are alkaloids?

Answer 2

Organic nitrogen-containing bases that have important physiological effects on animals.

Question 3

Give examples of alkaloids.

Answer 3

Nicotine
Quinine
Strychnine
Morphine

Question 4

What are biotic components?

Answer 4

Components of an ecosystem that are living.

Question 5

What is a pheromone?

Answer 5

Any chemical substance released by one living thing, which influences the behaviour or physiology of another living thing.

Question 6

What are tannins?

Answer 6

Phenolic compounds, located in cell vacuoles or in surface on wax plants.

Question 7

What is tropism?

Answer 7

A directional growth response in which the direction of the response is determined by the direction of the external stimulus.

Question 8

What are the plants responses to threats form herbivores?

Answer 8

Tannins
Alkaloids
Pheromones

Question 9

How are tannins a defense?

Answer 9

They are toxic to microorganisms and larger herbivores.

Question 10

Where annins found in the leaf of the plant?

Answer 10

They are found in the upper epidermis.

Question 11

What do annins do to the leaves?

Answer 11

Make them taste bad.

Question 12

What do annins do in the roots of plants?

Answer 12

Prevent infiltration by pathogenic microorganisms.

Question 13

What are alkaloids derived from?

Answer 13

Amino acids

Question 14

Where are alkaloids found in the plant?

Answer 14

In the growing tips and flowers, and peripheral cell layers of stems and roots.

Question 15

How are alkaloids a deterrent to animals?

Answer 15

They are a feeding deterrent as they taste bitter.

Question 16

What is phototropism?

Answer 16

Shoots grow towards the light, enabling them to photosyntheise

Question 17

What is geotropism?

Answer 17

Roots grow towards the pull of gravity

Question 18

Why do plants perform geotropism?

Answer 18

It anchors them into the soil and helps them to take up water/minerals.

Question 19

What is chemotropism?

Answer 19

On a flower, pollen tubes grow down the style, attracted by the chemicals, towards the ovary where fertilisation can take place.

Question 20

What is thigmotropism?

Answer 20

Shoots of climbing plants, such as ivy, wind around other plants or solid structure to gain support.

Question 21

What is a positive tropic response?

Answer 21

If a plant responds towards the stimulus.

Question 22

What is a negative tropic response?

Answer 22

If a plant responds away from a stimulus.

Question 23

What are non-directional responses towards a stimulus called?

Answer 23

Nastic response.

Question 24

The sensitive plant responds to touch. What is this called?

Answer 24

Thigmonasty

Question 25

How do hormones cause an effect in cells?

Answer 25

They bind reversibly to complimentary receptors on target cells plasma membrane causing a reaction to happen inside the cell.

Question 26

What does the hormone cytokinins cause?

Answer 26

Promotes cell division
Delay leaf senescence
Overcome apical dominance
Promote cell expansion

Question 27

What does the hormone abscisic acid cause?

Answer 27

Inhibits seed germination and growth

Causes stomatal closure when the plant is stressed by low water availability

Question 28

What do auxins do?

Answer 28

Promote cell elongation
Inhibit the growth of side shoots
Inhibit leaf abscission (leaf fall)

Question 29

What do gibberellins do?

Answer 29

Promote see germination and the growth of stems

Question 30

What does ethene do?

Answer 30

Promotes fruit ripening

Question 31

Give three methods that hormones use to move around the plant.

Answer 31

Active transport
Diffusion
Mass flow in the phloem sap or xylem vessels.