Chapter 39: Plant communication

Question 1

Factors plants respond to

Answer 1

light, heat/cold stress, hormones, gravity, touch, wounding, infection, drought, flooding

Question 2

how plants respond

Answer 2

altering growth/developement

Question 3

signal transduction pathways

Answer 3

link signal reception to response

Question 4

reception

Answer 4

signals are detected by receptors

Question 5

transduction

Answer 5

second messengers/relay proteins transfer and amplify signals

Question 6

response

Answer 6

regulation of one or more cellular activities

Question 7

protein kinases

Answer 7

work in a cascade linking initial stimuli to gene expression through phosphorylation of transcription factors

Question 8

protein phosphates

Answer 8

‘switch off’ the signal transduction pathways by dephosphorylating proteins

Question 9

transcriptional regulation

Answer 9

specific transcription factors bind directly to regions of DNA and control transcription of specific genes

Question 10

post-translational protein modification

Answer 10

activates pre-existing proteins; modification involves the phosphorylation of specific amino acids, alters the hydrophobicity and activity of the enzyme

Question 11

etiolation

Answer 11

physical adaptations for growing in the dark

Question 12

de-etiolation

Answer 12

greening process once a plant is exposed to light

Question 13

hormone

Answer 13

chemical signaling molecule

Question 14

how hormone works

Answer 14

produced in low concentrations in one part of the body and transported to other parts; binds to specific receptors and trigger responses in target cells and tissues

Question 15

auxin

Answer 15

chemical that promotes elongation of coleoptiles; cell elongation, apical dominance, fruit development, phototropism, gravitropism

Question 16

acid growth hypothesis

Answer 16

auxin stimulates proton pumps in the plasma membrane that lowers cell wall pH and increases the membrane potential to activate expansins that loosen the cell wall and enable expansion

Question 17

cytokinins

Answer 17

stimulate cytokinesis (cell division) with auxin; slow aging in plant organs

Question 18

gibberelins

Answer 18

affect stem elongation, fruit growth and seed germination

Question 19

abscisic acid (ABA)

Answer 19

slows growth; affects seed dormancy and drought tolerance

Question 20

ethylene

Answer 20

produced in response to stressors, ie. drought, flooding, mechanical pressure, injury, infection. Produced during fruit ripening and programmed cell death

Question 21

triple response to mechanical stress

Answer 21

slows stem elongation, strengthens stem, and causes to grow horizontally

Question 22

senescence

Answer 22

programmed cell death (apoptosis)

Question 23

leaf abscission

Answer 23

ethylene prevails over auxin to break leaf off at petiole

Question 24

photomorphogenesis

Answer 24

effects of light on plant morphology

Question 25

blue light photoreceptors

Answer 25

pigments that absorb blue light; initiates hypocotyl elongation, stomatal opening, phototropism

Question 26

cryptochromes

Answer 26

blue light receptors involved in the inhibition of cell elongation

Question 27

phototropin

Answer 27

mediates blue light mediated stomatal opening, chloroplast movements, and phototropic curvatures

Question 28

phytochrome photoreceptors

Answer 28

pigments that absorb mostly red and far-red light

Question 29

shade avoidance response

Answer 29

when tree is shaded, the phytochrome ratio shifts in favor of Pr, inducing vertical growth

Question 30

gravitropism

Answer 30

response to gravity

Question 31

thigmomorphogenesis

Answer 31

response to mechanical disturbance

Question 32

abiotic and biotic environmental stress

Answer 32

drought, flooding, salt, heat/cold stress