Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

module 5 > 5.1.5 - plant responses > Flashcards

5.1.5 - plant responses Flashcards

1
Q

tropisms

A

response to environmental cues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

limitations on plants

A

they are not mobile, and do not have a rapidly responding nervous system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

roles of auxin

A

control cell elongation, prevent leaf fall, maintain apical dominance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

roles of gibberellin

A

causes stem elongation, trigger the mobilisation of food stores in germination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

ethene

A

causes fruit ripening, and promotes abcission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

ABA

A

maintains dormancy of seeds and buds, stimulates cold protective responses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

seed germination process

A
  • seed absorbs water, embryo is activated and produces gibberellins
  • stimulates production of amylase and protease to break down food stores in seed
  • uses the glucose from breaking down, to produce ATP for building materials so it can grow and break out through the seed coat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

experimental evidence supporting the role of gibberellins in the germination of seeds

A
  • seeds that have been bred which lack the gene to make gibberellins, do not germinate.
  • if gibberellin biosynthesis inhibitors are applied to seeds they do not germinate as they cannot make the gibberellins needed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

how do auxins stimulate elongation?

A
  • binds to receptors on cell wall
  • releases H+ ions into the cell wall
  • this lowers the pH
  • this makes the cellulose more flexible
  • activates expansin enzymes
  • allows the cells to elongate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

apical dominance

A

growth in the main shoot is stimulated by the auxin produced at the tip so it grows quickly -lateral shoots are inhibited by the hormone that moves down the stem sp do not grow very well.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what happens to the lateral shoots if the apical shoot is removed

A

they are freed from the dominance of the apical shoot, so they grow faster

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

gibberellins role in elongation

A

affect the length of the internodes - the region between the leaves on a stem.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

synergism

A

different hormones working together, complementing eachother and giving a greater response than they would on their own

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

antagonism

A

different hormones having opposite effets, and the balance of these will determine the response of tge plant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

examples of abiotic stresses

A

changes in day length, cold and heat, lack of water, high winds, and changes in salinity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

why do some plants lose leaves in winter?

A

the conditions are not right for photosynthesis
waste of essential substances
may be blown by strong winds or heavy rainfall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

photoperiodism

A

plants are sensitive to a lack of light in their environment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

abcission

A

leaf fall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what happens to auxin levels, when light intensity falls

A

lowers the conc of auxin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

process of abcission

A
  • lower conc of auxin causes production of ethene
  • the ethene switches on genes in the abcission zone, producing new enzymes
  • these digest and weaken cell walls in the outer layer, becoming the separation layer
  • vascular bundles are sealed off
  • protective scar when leaf falls off, preventing entry of pathogens
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

why is it bad if cells freeze?

A

membranes will be disrupted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

adaptations for preventing freezing

A

cytoplasm of the plant cells and the sap in the vacuoles contain solutes whuch lower the freezing point.

sugars or proteins that act as antifreeze

23
Q

what hormone controls stomatal opening and closure?

A

ABA

24
Q

physical defences of plants

A

thorns, barbs, spikes, spiny leaves, fibrous and inedible tissue, hairy leaves etc

25
Q

chemical defences - tannins

A

bitter taste, which puts off animals eating the leaves, toxic to insects

26
Q

chemical defences - alkaloids

A

bitter tatsing, nitrogeneous compounds found in many plants, include caffeine or nicotine

27
Q

chemical defences - terpenoids

A

large group of compounds which act as toxins to insects and fungi that may attack the plant

28
Q

pheromone

A

chemical made by an organism which affects the social behaviour of other members of the same species.

29
Q

volatile organic compounds (VOCs)

A

act like pheromones between themselves and other organisms, diffusing through the air in and ariund the plant.

30
Q

examples of plants folding in response to touch

A

venus fly trap - when the leaves are touched, they fold down and collapse.

31
Q

phototropism

A

growth in plants in response to light

32
Q

geotropism

A

response to gravity

33
Q

chemotropism

A

response to chemicals

34
Q

thigmotropism

A

response to touch

35
Q

growth when there is all round light

A

the plant will grow straight and upwards, the auxin is distributed evenly

36
Q

growth when the light is on one side

A

the auxin will gather on the shady side, elongate, and the plant will slant towards the light

37
Q

roots and phototropism

A

roots grow away from the light

38
Q

example of forcing growth in plants

A

rhubarb

39
Q

etiolation

A

upward growth which takes place in a plant grown in the dark

40
Q

why are etiolated plants thin and pale?

A

no chloropyll because no light

41
Q

geotropism and shoots

A

negatively geotropic (they grow away frim gravity)

42
Q

roots and geotropism

A

positively geotropic (grow towards the gravitational pull)

43
Q

why do roots grow towards gravity?

A

to ensure they grow into the soil.

44
Q

which plant hormone is involved in ripening fruits?

A

ethene

45
Q

climareric

A

fruits that continue to ripen after they have been harvested
e.g. bananas, tomatoes and mangoes

46
Q

what happens to the ethene to cause ripening?

A

linke to a peak of ethene production triggering a series of chemical reactions including a greatly increased respiration rate.

47
Q

why is it important to control the ripening of fruit?

A

prevents wastage of fruit during transport and increases the time available for them to be sold.

48
Q

role of auxin in micropropagation

A

dipping the cut stem of a cutting into hormone rooting powder (contains auxin) to improve the chances of roots forming and of successful propogation taking place.

49
Q

what happens if the balance of the hormones in a plant is lost?

A

interrupt the metabolism of the whole plant and it may lead to plant death - this is sometimes useful for weeds etc

50
Q

why are weeds not good for crop yield?

A

interefere with crop plants, competing for light, space, water and minerals

51
Q

how do auxins deal with the problem of weeds?

A

scientists have developed synthetic auxins which act as very effective weedkillers - the plants absorb the auxins and affect the metabolism, becoming unbalanced and die. these do not affect the desired plants

52
Q

what hormone can be used in the production of seedless fruit?

A

auxins

53
Q

commercial use of cytokinins

A

prevent ageing of ripened fruit and products such as lettuces and in micropropagation to control tissue development

module 5 (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions