Module 5 - plant responses Flashcards

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1
Q

What is plant responses?

A

plants respond to changes in their environment in their environment to manage their chances of survival, e.g. towards the light to increase rate of photosynthesis

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2
Q

what is tropism?

A

the response to a plant to a directional stimulus

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3
Q

what are growth hormones?

A
  • Plants response to stimuli using growth hormones
  • as they have a circulatory system or a nervous systems like humans
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4
Q

What are auxins (IAA)?

A

they cause cell elongation in shoots (not cell division)

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5
Q

what are gibbrellins?

A
  • they responsible for controlling flowering and germination
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6
Q

what are common about all growth hormones?

A

they are made in the growing regions of the plants - root tips and shoot tips

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7
Q

how do growth hormones move short distances?

A
  • move short diffusion by diffusion and active transport
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8
Q

where do growth hormones move long distances?

A

in the phloem

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9
Q

what happens in phototropism?

A

IAA moves to the shaded side of the shoot/root

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10
Q

what happens in geotropism?

A

IAA always move to the underside

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11
Q

In shoots, what happens in phototropism?

A

IAA causes cell elongation, shoots grow towards the light

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12
Q

In roots, what happens in phototropism?

A

IAA inhibits cell growth -> roots grow towards the light

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13
Q

In shoots, what happens in geotropism?

A
  • grow way from gravity, - - - cell elongation
  • negative geotropism
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14
Q

In roots, what happens in geotropism?

A
  • grow towards gravity
  • Positive geotropism
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15
Q

Plant responses to herbitory - what happens when chemical are released?

A
  • bitter/bad tasting
    -toxic
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16
Q

Plant responses to herbitory - example of a chemical

A
  • Tannins -> toxic -> Inhibit enzyme in insects
  • Alkeloids e.g. caffeine and cocaine
  • attract herbivores - attract wasps to eat caterpillars
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17
Q

Plant responses to herbitory - give examples of sting or thornes

A

e.g. stinging nettles such as roses

18
Q

Plant responses to herbitory - how does folding leaves work?

A
  • folds leaves in half quickly
  • dislodge small insect herbivores
19
Q

Plant responses to herbitory - example of folding leaves?

A

mimosa

20
Q

explain the steps of apical dominance?

A
  • Apical bud at the top of the stem produces auxin e.g. IAA
  • auxins promote growth at the apical bud
  • auxin inhibits growth of the lateral buds
  • plant grows taller and doesn’t compete with itself
  • apical bud is dominant over lateral bud
  • auxin concentration decreases with distances from apical bud -> lateral buds further from apical bud are less inhibited
21
Q

what happens if we remove the apical bud?

A

-if the apical bud is removed, less auxin is made
- lateral buds are not inhibited
-> start to develop
- becomes bushy
- if auxin is added to top of of cut stem
- apical dominance continues

22
Q

what are an example of auxins?

A

IAA

23
Q

Give an example of gibrellins ?

A

Gibbrellic acid

24
Q

where are auxins made?

A
  • root tips
  • shoot tips
  • young leaves
  • growing parts of the plants
25
Q

where are gibrellins made?

A
  • seeds
  • young leaves
26
Q

where is ethene made?

A
  • old leaves
  • ripening fruit
27
Q

give an example of absiisic acids?

A

ABA

28
Q

what causes growth of auxins?

A
  • growth in shoots by cell division
29
Q

what promotes gibrellins?

A
  • seed germination
  • flowering
  • stem elongation
  • lateral shoot growth
30
Q

what promotes ethene?

A
  • leaf loss/drop
  • fruit ripening
31
Q

what promotes Abscissic acid?

A
  • closing stomata
32
Q

what inhibits auxins?

A
  • growth in root tips
  • leaf loss
33
Q

what inhibits abscissic aicd?

A
  • gibrellins (seed germination)
34
Q

what is the commercial use of auxins?

A
  • rooting powders
  • weed killers
35
Q

what is the commercial use of gibrellins?

A

seedless grapes

36
Q

what is the commercial use of ethene?

A
  • ripen demands in supermarkets
37
Q

what is the commercial use of abscissic acid?

A

reduces drought stress

38
Q

What happens in stomata closure?

A
  • stomata closes to secure water (transpiration)
  • guard cells turgid - open
    -ABA binds to receptors in guard cell membrane
  • open calcium and potassium channels
    ions diffuse out of guard cells
  • increases water potential of guard cells
    water will leave the guard cell by osmosis - flaccid - stomata closes
39
Q

explain leaf loss by ethene?

A
  • old leaves make ethene
  • causes layer of cells in stalk of leave to expand and break
  • leaf falls
  • water and nutrients
40
Q

Explain seed germination?

A

starch is hydrolysed into glucose in seeds
- glucose is respired (ATP)
- seeds can germinate