Chapter 39: Plant Hormones

Question 1

Secondary Messengers and Transduction

Answer 1

Small molecules and ions in the cell that amplift signals and transfer it from the receptor to other proteins that carry out the response

Question 2

Hormone

Answer 2

Signaling molecule that is produced in low concentration by one part of an organism;s body and transported to other parts, where it binds to a specific receptor and triggers responses in target cells and tissues

Question 3

Plant Hormone or Plant growth Regulator

Answer 3

Organic compounds, that modify or control one or more specific physiological processes within a plant

Question 4

Tropism

Answer 4

A growth response that results in the curvature of whole plant organs towards or away from stimuli due to differential rates of cell elongation.

Question 5

Phototropism

Answer 5

The bending of a plant or other organism in response to light, either towards or awat from it

Question 6

Auxin

Answer 6

A natural plant hormone that effects cell elongation, root formation, secondary growth, and fruit growth

Question 7

Expansin

Answer 7

Plant enzyme that breaks the cross-links between cellulose microfibrils and other cell wall consituents, loosening the wall’s fabric

Question 8

Cytokinins

Answer 8

Any plant hormone that retards agins and act in concert with auxin to stimulate cell division, influence the pathway of differentiation, and control apical dominance

Question 9

Gibberellin

Answer 9

Any plant hormone that stimulates growth in the stems and leaves, trigger the germination of seeds and breaking of bud dormancy, and stimulate fruit development

Question 10

Abscisic Acid (ABA)

Answer 10

Involved in seed dormancy and drought tolerance

Question 11

Ethylene

Answer 11

A gaseous plant hormone released in response to mechanical stress, programmed cell death, leaf abscission, and fruit ripening

Question 12

Triple response

Answer 12

A plant maneuver in response to mechanical stress, involving slowing of stem elongation, thickening of the stem, and a curvature that causes the stem to start growing horizontally.

Question 13

Senescence

Answer 13

The programmed death of certain cells, organs, or the entire organism

Question 14

Brassinosteroids

Answer 14

A steroid hormone in plants that has a variety of effects, including inducing cell elongation, retarding leaf abscission, and promoting xylem differentiation

Question 15

Jasmonates

Answer 15

Any of a class of plant hormones that inhibit shoot branching, trigger the germination of parastic plant seeds, and stimulate the assocation of plant roots with mycorrhizal fungi

Question 16

Strigolactones

Answer 16

Any of a class of plant hormones that inhibit shoot branching, trigger the germination of parasitic plant seeds, and stimulate the association of plant roots with mycorrhizal fungi

Question 17

Gravitropism

Answer 17

A response of plants or animals to gravity

Question 18

Statolith

Answer 18

In plants, a specialized plastic that contains dense starch grains and may play a role in detecting gravity

Question 19

Thigmomorphogenesis

Answer 19

A response in plants to chronic mechanical stimulation, resulting from indreasing ethylene production. An example is thickening stems in response to strong wing

Question 20

Thigmotropism

Answer 20

A directed growth of a plant in response to touch

Question 21

Pathogen associated molecular pattern

Answer 21

A molceular sequence that is specific to a certain pathogen

Question 22

Effector

Answer 22

A pathogen encoded protein that cripples the host’s innate immune system

Question 23

Hypersensative Response

Answer 23

A plant’s localized defense in response to a pathogen, involving the death of cells around the site of infection

Question 24

Systemic aquired resistance

Answer 24

A defense response in infected plants that protects healthy tissue from pathogenic invasion

Question 25

Salicytic Acid

Answer 25

A signaling molecule in plants that may be partially responsible for activating systemic acquired resistance to pathogens

Question 26

Photomorphogenesis

Answer 26

Effects of light on plant morphology

Question 27

Blue-Light Photoreceptors

Answer 27

Light-absorbing molecules that have physiological effcts when activated by blue light

Question 28

Phytochromes

Answer 28

Plant pigment that absorbs mostly red and far-red liht and regulate many plant responses, such as seed germination and shade avoidance

Question 29

Photoperiodism

Answer 29

A physiological response to photoperiod, the interval in a 24-hour period during which an organism is exposed to light

Question 30

Short-day plant

Answer 30

A plant that flowers only when the light period is shorter than a critical length

Question 31

Long day plant

Answer 31

A plant that flowers only when the light period is longer than a critical length

Question 32

Day neutral plants

Answer 32

A plant in which flower formation is not controlled by a photo period or day length

Question 33

Vernalization

Answer 33

the use of cold treatment to induce a plant to flower

Question 34

Florigen

Answer 34

A flowering signal that is made in leaves under certain conditions and that travels to the shoot apical meristems, inducing them to swtich from vegetative to reproductive growth.