plant and animal responses

Question 1

What are biotic factors

Answer 1

Living factors

Question 2

What are abiotic factors

Answer 2

Non living

Question 3

What are the types of stimuli

Chemical defenses

Answer 3

Tannins
Alkaloids
Pheromones

Question 4

Describe tannins

Answer 4

Are toxic microorganisms and larger herbivores. In leaves they are found in the upper epidermis , and make the leaf taste bad . In roots they prevent infiltration by pathogenic microorganisms

Question 5

Describe alkaloids

Answer 5

Are derived from amino acids . in plants scientists think that are a feeding deterrent to animals , tasting bitter . They are located in growing tips and flowers and peripheral cell layers of stems and roots

Question 6

Describe pheromones

Answer 6

Are chemicals which are released by one individual and which can effect the behaviour or physiology of another

Question 7

What are the types of responses

Answer 7

Phototropism
Geotropism
chemotropism
thigmotropism

Question 8

define tropism

Answer 8

a directional growth response in which the direction of the response is determined by the direction of the external stimuli

Question 9

describe phototropism

Answer 9

shoots grow towards light ( they are positively phototrophic ) , which enables them to photosynthesis

Question 10

describe geotropism

Answer 10

roots grow towards the pull of gravity. this anchors them in the soil and helps them to take up water , which is needed for support (to keep cells turgid ) as a raw material for photosynthesis and to help cool the plant . there will also be minerals such as nitrates in the water needed for the synthesis of amino acids

Question 11

describe chemotropism

Answer 11

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

Question 12

describe thigmotropism

Answer 12

shoots of climbing plants such as ivy , wind around other plants or solid structures to gain support

Question 13

if a plant responds towards a stimuli it is called

if a plant responds away from a stimulus it is called

Answer 13

positive tropic

negative tropic

Question 14

non directional responses to external stimuli are called

Answer 14

nastic responses

Question 15

describe the hormone action

Answer 15

• produced by specific cells
• reach target cells
• bind to receptors on the plasma membrane
• specific hormones have specific shapes which can only bind to specific receptors with complementary shapes

Question 16

hormones move around the plant in any of the following way

Answer 16

• active transport
• diffusion
• mass flow

Question 17

describe cytokinins effect

Answer 17

• promotes cell division
• delay leaf senescence
• overcome apical dominance
• promote cell expansion

Question 18

describe abscisic acid effect

Answer 18

• inhibits seed germination and growth

- causes stomatal closure when the plant is stressed by low water availability

Question 19

describe auxins

Answer 19

• promotes cell growth
• inhibits growth of side shoots
• inhibit leaf abscission

Question 20

describe gibberellins

Answer 20

-promotes seed germination and growth of stems

Question 21

describe ethene

Answer 21

promotes fruit ripening

Question 22

if you break the shoot tip off the plant, what happens to the plant

Answer 22

the plant starts to grow side branches from the lateral buds that were previously dormant

Question 23

describe the experiment and research on auxins

Answer 23

research suggested that auxins from the apical bud prevent lateral buds from growing . when the tip is removed , auxin levels in the shoot drops and buds grow