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Plant development and environmental perception Flashcards

plant development cellular aspects of development how cells respond to stimuli

1
Q

what are angiosperms

A

plants that have flowers and produce seeds enclosed within a carpel

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2
Q

what are the two main groups of angiosperms

A

eudicots and monocots

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3
Q

what is a cell

A

the fundamental unit of life

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4
Q

what is a tissue

A

a group of cells consisting of one or more cell types that together perform a specialized function

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5
Q

what is an organ

A

it consists of several types of tissues that together carry out particular functions

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6
Q

what do plants absorb below the ground

A

water and minerals

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7
Q

what do plants absorb above the ground

A

light and carbon dioxide

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8
Q

what are the 3 basic organs of a plant

A

stems, leaves and roots

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9
Q

what does the root system consist of

A

the roots

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10
Q

what does the shoot system consist of

A

stems and leaves

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11
Q

what is a root

A

an organ that anchors a vascular plant in the soil, absorbs minerals and water and often stores carbohydrates and other reserves

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12
Q

what is the first organ to emerge from a germinating seed

A

the primary root

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13
Q

what does the primary root branch into

A

lateral roots

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14
Q

what is a taproot

A

the main vertical root that develops from the primary root and is exhibited in tall erect plants - facilitates anchorage

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15
Q

what is a fibrous root system

A

a thick mat of slender roots spreading out below the soil surface

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16
Q

what is an adventitious root

A

a root that grows in an unusual location e.g. roots arising from stems or leaves

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17
Q

what are root hairs

A

thin finger like extensions of root epidermal cells

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18
Q

what are mycorrhizal associations

A

root symbiotic interactions with soil and fungi that increase a plants ability to absorb minerals

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19
Q

what is a stem

A

a plant organ bearing leaves and buds
its chief function is to elongate and orient the shoot in a way that maximises photosynthesis by the leaves
they also elevate reproductive structures, facilitating the dispersal of pollen and fruit

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20
Q

can a green stem perform photosynthesis

A

yes but it is limited

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21
Q

stems consist of nodes, what are these

A

the points at which leaves are attached

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22
Q

stems consist of internodes, what are these

A

the stem segments between nodes (between the points where leaves are attached

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23
Q

what is the main photosynthetic organ

A

the leaves

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24
Q

how do monocots and eudicots differ

A

by the arrangement of veins ((the vascular tissue) in the leaves

  • most monocots have parallel veins
  • most eudicots have a branched network of veins arising from a major vein
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25
Q

what are the 3 fundamental tissue types of vascular plants

A

dermal, vascular and ground tissues

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26
Q

what is the function of the dermal tissue system

A

serves as an outer protective covering of the plant

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27
Q

what are the functions of trichomes

A

reduce water loss
reflect excess light
defend against insects

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28
Q

what is the function of the vascular tissue system

A

facilitates the transport of materials through the plant and provide mechanical support

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29
Q

what are the 2 types of vascular tissue

A

xylem and phloem

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30
Q

what is the function of xylem

A

conduct water and dissolved minerals upward from roots into the shoots

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31
Q

what is the function of phloem

A

transports sugars from where they are made to where they are needed or stored

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32
Q

what is ground tissue

A

tissue that is not vascular or dermal - it includes specialised cells for functions such as storage, photosynthesis, support and short distance transport

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33
Q

what is intermediate growth

A

the process of plants growing throughout their life

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34
Q

why can plants continually grow

A

because they have undifferentiated tissues called meristems, containing cells that can divide, leading to new cells that elongate and become differentiated

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35
Q

which type of plant does not grow continuously

A

dormant plants

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36
Q

describe the growth of most animals

A

determinate growth - they stop growing after they reach a certain size

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37
Q

what are the 2 main types of meristems and what type of growth do they enable

A

apical meristem - primary - length

lateral meristems - secondary - thickness

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38
Q

roots and stems grow intermediately/determinately

A

intermediately

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39
Q

leaves grow intermediately/determinately

A

determinately - because the oldest leaves at the bottom of the plant would be large and heavily shaded, unable to photosynthesise maximally

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40
Q

what is the function of stomata

A

they are pores interrupting the leaf epidermis which allow exchange of carbon dioxide and oxygen between the surrounding air and the photosynthetic cells in side the leaf
they are also major avenues for the evaporative loss of water

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41
Q

what does the stomatal complex consist of

A

a stomatal pore flanked by 2 specialised epidermal cells known as guard cells which regulate the opening and closing of the pore

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42
Q

what is a parenchyma cell

A

a relatively unspecialised plant cell type that carries out most of the metabolism, synthesis and stores most of the organic products and develops into a more differentiated cell type

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43
Q

what type of cell does mesophyll mainly consist of

A

parenchyma

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44
Q

what is a bundle sheath

A

a layer of cells that encloses the veins and regulates the movement of substances between the vascular tissue and the mesophyll
(prominent in leaves that carry out C4 synthesis)

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45
Q

contrast primary growth in roots and shoots

A

roots - primary growth occurs in 3 successive stages, moving away from the tip of the root: the zones of cell division, elongation and differentiation
shoots - occurs at the tip of apical buds, with leaf primordia arising along the sides of an apical meristem - most growth in length occurs in older internodes below the shoot tip

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46
Q

what are leaf primordia

A

finger like projections along a shoot apical meristems from which a leaf arises

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47
Q

what is a lenticel

A

a small raised area in the bark of stems and roots that enabled gas exchange between living cells and the outside air

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48
Q

why do stomata need to be able to close but lenticel s do not

A

stomata need to close because water evaporation is much more intensive in leaves than from the trunks of woody trees as a result of higher SA to volume ratio in leaves

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49
Q

what is meant by plant growth being modular

A

it follows patterns that are repeated over and over again

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50
Q

what does morphogenesis (plant form) arise from and what is it dependent on

A

arises within cell walls and depends entirely on cell division and cell lineage

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51
Q

the first 4 divisions of embryogenesis give cell ……….

A

bulk

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52
Q

the fifth division (to 16 cell stage) results in what

A

cell layers

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53
Q

tripoblasts/atripoblasts form root hairs

A

triipoblasts

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54
Q

tripoblasts/atripoblasts do not form root hairs

A

atripoblasts

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55
Q

what happens to the fassiculated mutant of Arabidopsis

A

it has a loss of positional interactions - the cell walls become disorganised

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56
Q

what happens to the knolle mutant of Arabidopsis

A

it has a loss of cell division control - knolle is a structural protein needed to form the cell division plate - the mutant has irregular and incomplete cell divisions

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57
Q

simple rules of association provide guidelines for what

A

development

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58
Q

what is pattern formation

A

the development of specific structures in specific locations

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59
Q

where do plant developmental stages (phases) occur

A

the apical shoot meristem

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60
Q

what are phase changes

A

in plants it is a morphological change that arises from a transition in shoot apical meristem activity

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61
Q

what does GLABRA-2 do

A

if it is expressed the cell is hairless but if it isn’t expressed then the cell will develop a root hair

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62
Q

do nodes and internodes maintain juvenile status even after the shoot apical meristem has changed to adult phase

A

yes - new leaves that develop at juvenile nodes will also be juvenile even though the apical meristem is producing mature nodes

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63
Q

describe 3 difference between animal and plant development

A

plants:

  • intermediate growth
  • juvenile and mature phases are found on the same plant
  • cell differentiation is more dependent on final position

animals:

  • determinate growth
  • juvenile and mature phases not found on the same individual
  • cell differentiation is more dependent on cell lineage
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64
Q

what phase change does flower formation involve

A

a change from vegetative growth to reproductive growth

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65
Q

is floral growth usually indeterminate or determinate

A

determinate

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66
Q

how does the production of a flower by a shoot apical meristem affect growth

A

it usually stops the primary growth of that shoot

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67
Q

which genes control the switch from vegetative growth to flowering

A

meristem identity genes

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68
Q

how do meristem identity genes affect flowering

A

their protein product acts as a transcription factor that regulates the genes required for the conversion of intermediate vegetative meristems to determinate floral meristems

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69
Q

what are the 4 floral organs

A

sepal, petal, stamen or carpel

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70
Q

what do organ identity genes belonging to the MADS-box family encode

A

transcription factors that regulate development of the characteristic floral pattern

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71
Q

what can a mutation in organ identity genes in plants cause

A

abnormal floral development such as petals growing in place of stamens

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72
Q

what process leads to polarisation

A

germination

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73
Q

what factors induce germination

A
  • light (rhizoid grows on shaded side)
  • heat (rhizoid grows on warm side)
  • osmotic gradient (rhizoid grows towards water)
  • pH (rhizoid grows towards alkaline pH)
  • salt rhizoid grows towards salt)
  • fertilization (rhizoid at entry point)
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74
Q

describe the steps in polarisation due to fertilisation

A
  • in fertilisation, a calcium wave triggers secretion of cell wall material
  • calcium current is initiated and enters at future rhizoid end
  • actin is organised, and secretion is directed to future rhizoid
  • polarity is fixed and the rhizoid tip is visible
  • mitosis and cell division occur
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75
Q

what are rhizoids

A

long tubular single cells

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76
Q

what is the regulatory factor of polarity

A

calcium

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77
Q

root structure arises from ……….. divisions that initiate cell lineage

A

meristems

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78
Q

how is polarity controlled between cells in plants

A

Apical-basal polarity is maintained by hormonal gradients, especially auxin

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79
Q

Plant tissue structure arises from cell lineages with defined cell fates originating from established ……………

A

cell polarity

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80
Q

what do pin proteins do

A

transport auxins out of cells (efflux carriers)

81
Q

what happens to the pin-1 mutant

A

disturbs shoot form and root growth direction

82
Q

what happens to the pin-2 mutant

A

mutant seedlings show loss of gravitropism (movement or growth in relation to gravity) in the root - they can’t access nutrients and water from the soil as well

83
Q

in signal transduction what is a receptor need for

A

to sense the stimulus - the receptor converts the signal into a biological meaningful form

84
Q

what are second messengers

A
  • they amplify the internal biochemical signal from the receptor
  • they transfer the signal to the response mechanism
85
Q

by opening and closing of stomata, what is balanced

A

the need for CO2 for photosynthesis against the prevention of water loss

86
Q

abscisic acid is involved in which kind of tress

A

drought - drought stimulates roots to synthesise abscisic acid which then travels to the leaves with the transpiration stream

87
Q

is abscisic acid a stimulus for stomatal closure or opening

A

closure

88
Q

the abscisic acid stimulus overrides the need for ……….

A

CO2

89
Q

what are the 3 main ion channels used by guard cells

A

Ca
Cl
K

90
Q

how can we measure ion channels

A

using a method called clamping

we can also measure how single proteins function using a method called patch lamp

91
Q

ion channels are pores with …………. gates

A

regulated

92
Q

how does gating of ion channels arise

A

from changes in protein conformation in the channel

93
Q

how does abscisic acid trigger closing of stomata

A

it triggers potassium and chlorine efflux and suppresses influx which triggers closing of the stomata
the abscisic acid affects the gating of the channels affecting their frequency of opening

94
Q

what are jaffes laws

A

the laws for determining if something is a secondary messenger

  1. the stimulus, second messenger and response must be related in time and space
  2. blocking a signal or messenger must block the signal and response downstream
  3. introducing a second messenger without a primary stimulus must give the response downstream
95
Q

abscisic acid triggers a rise/decrease in Ca in the cytosol

A

rise

96
Q

Ca is needed to regulate what

A

ion channels

97
Q

Ca in the cytosol promotes/suppresses abscisic acid action on K and Cl channels

A

suppresses

98
Q

is Ca sufficient to regulate ion channels without abscisic acid

A

yes

99
Q

give examples of stimuli that trigger signal transduction pathways

A

light
hormones
physical environment
pathogens

100
Q

signal transduction pathways link signal ………. to ………….

A

reception to response

101
Q

what is etiolation

A

morphological adaptations for growing in darkness

102
Q

describe a dark grown potato

A

tall stems and unexpanded leaves - an adaptation enabling shoots to penetrate the soil
the roots are short as there is little need for water absorption due to the lack of water loss due to the lack of leaves

103
Q

describe a potato grown in light

A

short sturdy stems
broad green leaves - to enhance photosynthesis
long roots - to enhance water absorption

104
Q

what is de-etiolation

A

the changes a plant undergoes due to being exposed to light

the light signal is transduced to de-etiolation response

105
Q

what are the 3 main steps of a signal transduction pathway

A

reception
transduction
response

106
Q

what are signals detected by

A

receptors

107
Q

what is the receptor involved in de-etiolation

A

phytochrome

108
Q

where is the phytochrome located

A

cytoplasm

109
Q

where are the majority of photoreceptors found

A

the plasma membrane

110
Q

what causes golden rice

A

it is an aurea mutant which has less phytochrome (this reduces the level of chlorophyll because phytochromes detect red light that chlorophyll absorbs)
in the absence of chlorophyll the yellow and orange accessory pigments become more prominent

111
Q

cytosolic changes in calcium concentration play an important role in ………… signal transduction

A

phytochrome

112
Q

how do phytochromes affect calcium concentration

A
  • phytochrome activation leads to the opening of calcium channels increasing cytosolic levels of calcium
113
Q

describe the role of phytochrome in de-etiolation

A
  1. light signal is detected by the phytochrome receptor, activating 2 signal transduction pathways
  2. a. one pathway uses cGMP as a second messenger that activates kinase
    b. the other pathway increases the cytosolic level of calcium which activates another kinase
  3. both pathways lead to the expression of genes (by transcription factors activated by kinase) for proteins that function in the de-etiolation response
114
Q

what are the 2 main mechanisms by which a signalling pathway can enhance an enzymatic step in a biochemical pathway

A

transcriptional regulation

post translational modification

115
Q

what is transcriptional regulation

A

controlling the level of mRNA encoding a specific enzyme

116
Q

what do post translational modifications do

A

activate pre-existing enzymes

117
Q

give examples of post translational modifications

A

phosphorylation

118
Q

what enzymes are important in stopping signal transduction pathways after the stimulus has faded

A

phosphatases - they dephosphorylate

119
Q

what are the 2 types of transcription factors

A

activators (increase transcription) and suppressors (decrease transcription)

120
Q

why is etiolation advantageous

A

etiolated growth is beneficial to seeds growing underground or under dark conditions.
by devoting more energy to stem elongation and less to leaf expansion and root growth, the plant increases the likelihood that the shoot will reach the sunlight before its stored food runs out

121
Q

which hormones enhance stem elongation

A

auxin and brassinosteroids

122
Q

what is a hormone

A

signalling molecule that is produced in low concentrations by one part of an organism and is transported to other parts triggering responses in target cells and tissues

123
Q

what are plant growth regulators

A

plant hormones

124
Q

where is auxin found

A

shoot apical meristems and young leaves

125
Q

what is the function of auxin

A

simulates stem elongation
promotes formation of lateral and adventitious roots
regulates development of fruit
functions in phototropism and gravitropism

126
Q

where are cytokinins found

A

mostly synthesised in the roots - and are transported in the xylem sap

127
Q

what is the function of cytokinins

A

regulation of cell division in roots and shoots
promote movement of nutrients
stimulates seed germination

128
Q

where is ABA found

A

almost all plant cells have the ability to produce ABA

129
Q

what is the function of ABA

A

inhibits growth
promotes stomatal closure during drought stress
promotes seed dormancy and inhibits early germination

130
Q

what is a tropism

A

any growth response that results in plant organs curving towards or away from light

131
Q

what is phototropism

A

the growth of a shoot towards or away from light

132
Q

why do high concentrations of auxin inhibit growth

A

high auxin concentrations may induce production of ethylene which hinders growth

133
Q

explain how proton pumps play a major role in the growth response of cells to auxin

A
  • in a shoots region of elongation, auxin stimulates the plasma membranes proton pumps pumping H from the cytoplasm
  • H increases the voltage across the membrane and lowers the pH in the cell wall
  • acidification of the cell wall activates proteins that break H bonds between cell wall constituents, making the cell wall more flexible
  • increasing the membrane potential enhances ion uptake into the cell which causes osmotic uptake of water and increased turgor
  • increased turgor and increased cell wall plasticity enable the cell to elongate
134
Q

what is IBA used for

A

it is used in the vegetative propagation of plants by cuttings
treating a detached leaf or stem with IBA often causes adventitious roots to form near the cut surface

135
Q

why are synthetic auxins used as herbicides

A

they can be quickly broken down by monocots but overdose eudicots, eliminating eudicot weeds

136
Q

what is apical dominance

A

the ability of the apical bud to suppress development of auxiliary buds (controlled by various hormones including auxin and cytokinins)

137
Q

how do cytokinins slow aging

A

they inhibit protein breakdown and stimulate RNA and protein synthesis

138
Q

what is the role of gibberellins

A

stimulate stem elongation, pollen development, fruit growth, germination

139
Q

what is the function of ethylene

A

promotes fruit ripening, leaf abscission, promotes root hair formation
induces triple response in seedlings

140
Q

what is the function of brassinosteroids

A

promotes root growth at low concentrations but inhibits it at high concentrations

141
Q

what is the ABA response to drought

A
  • ABA accumulates in the leaves
  • by affecting the second messenger, Ca, ABA cause potassium channels in the plasma membrane of guard cells to open leading to a massive loss of potassium ions from cells
  • the accompanying osmotic loss of water reduces guard cell turgor and leads to the closing of the stomatal pores
  • as a result less transpiration occurs
142
Q

many plants prone to wilting are deficient in what

A

ABA - it acts as a drought signal

143
Q

what is the triple response induced by ethylene

A

it enables seedling shoots too avid obstacles
the 3 parts of the response are:
- slowing of stem elongation
- thickening of stem
- stem curvature that causes it to start growing horizontally
the stem resumes regular growth after the ethylene pulse lessens

144
Q

what is senescence

A

the programmed cell death of certain cells or organs or the entire plant - ethylene is almost always associated with apoptosis in senescence

145
Q

what is abscission and what is it controlled by

A

the natural detachment of parts of a plant, typically dead leaves and ripe fruit
it is controlled by a change in the ratio of ethylene to auxin. an aging leaf produces less and less auxin rendering the abscission layer more sensitive to ethylene. when ethylene targets the abscission layer, the cells produce enzymes which digest cell wall components

146
Q

what forms after leaf abscission to protect the plant from pathogens

A

a protective layer forms on the remaining twig to prevent pathogen entry

147
Q

what triggers the ripening of fruit

A

a burst of ethylene - the enzymatic breakdown of cell wall components softens the fruit and conversion of starches and acids to sugars makes the fruit sweeter

148
Q

how do gibberellins promote stem elongation

A

they enhance cell elongation and cell division
- they activate enzymes that loosen cell walls allowing the entry of expansins - which along with auxin promote cell elongation

149
Q

in many plants, ………….. and …………. must be present to allow fruit to develop

A

auxin and gibberellins

150
Q

which hormone signals seeds to break dormancy and germinate

A

gibberellins

151
Q

what are brassinosteroids similar to in animals

A

sex hormones and cholesterol

152
Q

which hormone slows leaf abscission

A

brassinosteroids

153
Q

what are tumour growths on leaves caused by

A

uncontrolled cell division and cell differentiation - can be caused by pathogens interfering with the function of auxin and cytokinin

154
Q

what are ein mutants

A

ethylene insensitive mutants - they fail to undergo the triple response - they lack the ethylene receptor

155
Q

what are eto mutants

A

ethylene overproducing mutants - they undergo the triple response

156
Q

what are ctr mutants

A

constitutive triple response mutants - they don’t respond to inhibitors of ethylene synthesis so the ethylene signal transduction pathway is permanently turned on even id ethylene is absent

157
Q

what is photomorphogenesis

A

the effects of light on plant morphology

158
Q

what does an action spectrum show

A

the relative effectiveness of different wavelength of radiation in driving a particular process

159
Q

what are the 2 major classes of light receptors

A

blue light photoreceptors - regulate phototropism, stomatal opening, slowing of hypocotyl elongation when a seedling breaks ground
phytochromes - regulate seed germination and shade avoidance

160
Q

what is phototropism

A

growth of a plant shoot towards or away from light

161
Q

which blue light photoreceptor is involved in mediating stomatal opening

A

phototropin (a protein kinase)

162
Q

describe the role of phytochrome in the germination process

A

Pr in lettuce seeds exposed to red light is converted to Pfr stimulating germination.
when the red illuminated seeds are then exposed to far red light Pfr is converted back to Pr inhibiting germination
in nature the conversion to Pfr is faster than the conversion to Pr so germination is promoted

163
Q

if a plant is exposed to multiple flashes of light, which flash will create the response

A

the last flash - the final light exposure is the determining factor

164
Q

describe the role of phytochromes in shading avoidance

A
  • if other trees in a forest shade a tree the phytochrome ratio will shift in favour of Pr because the - forest canopy screens out more red than far red light
  • this is because pigments in the leaves of the canopy absorb red light and transmit far red light
  • the shift in the ratio of red to far red light induces the tree allocates more of its resources to growing taller
  • in contrast direct sunlight increases the proportion of Pfr which stimulates branching and inhibits vertical growth
165
Q

what is a circadian rhythm

A

cycles with a frequency of 24 hours that are not directly controlled by an environmental variable

166
Q

what is photoperiodism

A

a physiological response to specific night or day lengths e.g. flowering

167
Q

what is a short day plant

A

they require a light period shorter than the critical length to flower (flower in winter instead of summer when light hours decrease)

168
Q

what are long day plants

A

they require a light period longer than the critical length to flower (they flower in spring or early summer )when the photoperiod is long)

169
Q

what are day neutral plants

A

they are unaffected by photoperiod and flower when they reach a certain stage of maturity

170
Q

is flowering in short day and long day plants controlled by night length or day length

A

night length - so short day plants are actually long night plants and long day plants are actually short night plants

171
Q

long day plants - maximum/minimum number of hours of darkness

A

maximum

172
Q

short day plants - maximum/minimum number of hours of darkness

A

minimum

173
Q

which colour of light is most effective in interrupting night length

A

red

174
Q

where on the plant do flowers form

A

from apical or auxiliary bud meristems

175
Q

which part of the plant detects changes in the photoperiod

A

leaves - they produce signalling molecules that cu bud to develop as flowers

176
Q

how is flowering initiated

A

a gene called FT is activated in leaf cells in conditions favourable for flowering
the FT protein travels to the shoot apical meristem initiating the transition of a bud meristem from vegetative to flowering state

177
Q

what is gravitropism

A

a plants response to gravity
roots display positive gravitropism (growing in direction of gravity) and shoots exhibit negative gravitropism (growing against gravity)

178
Q

what is thigmomorphogenesis

A

changes in form that result from touch (mechanical perturbation)

179
Q

what is thigmotropism

A

directional growth in response to touch

180
Q

on a dry sunny day why does a plant wilt

A

it water loss by transpiration exceeds water absorption from the soil.

181
Q

why may an overwatered house plant suffocate

A

the soil lack air spaces that provide oxygen for cellular respiration in the roots
- oxygen deprivation can induce ethylene production which causes some cells in the root cortex to die. this creates air space so oxygen can be taken up for respiration

182
Q

how does salt affect plants

A

if plant soil is too salty this prevent water uptake into the plant

183
Q

how do plants cope with cold stress

A

they alter their membrane lipid composition to keep it fluid - they increase the proportion of unsaturated fatty acid keeping the membrane fluid at low temperatures

184
Q

how do plants cope with frost

A

when they freeze, water leaves the cytoplasm to go to the cell wall
the increase in the concentration of ions in the cytoplasm is harmful to the plant
plant have adapted by increasing cytoplasmic levels of specific solutes that are tolerated by the plant and help reduce the loss of water from the cell during extracellular freezing
unsaturation of membrane lipids is also increased helping to maintain fluidity

185
Q

why are plant that are producing ABA warmer

A

because they cant undergo as much transpiration (evaporative cooling) due to stomatal closure

186
Q

give an example of how plants can invade pathogens

A

by entering through openings in the epidermis e.g. the stomata

187
Q

do plants have an adaptive immune system

A

no only an innate immune system

188
Q

what are the 2 immune responses of plants to pathogens

A
  1. PAMP - pathogen associated molecular patterns

2. effector triggered immunity

189
Q

what is the hypersensitive response

A

a plants localised specific defence response to a pathogen, involving the death of cells around the site of infection, preventing the spread of the infection

190
Q

what is systematic acquired resistance

A

a defensive response in infected plants that helps protect healthy tissue from pathogenic invasion – a plant wide response (not localised)

191
Q

what are the steps in defence responses of plants against pathogens

A
  1. pathogens infect leaf cells and secrete effectors, proteins that bypass PAMP immunity
  2. hypersensitive response occurs in response to effectors
  3. before infected cell die they release a signalling molecule (methysalicylic acid) to the rest of the plant
  4. the signalling molecule is converted to salicylic acid which induces systematic acquired resistance protecting the plant against many pathogens for several days
192
Q

why is calcium effective as a second messenger in plants

A

because it is poorly mobile and largely bound in the cytosol

193
Q

how many genes are involved in plant development

A

3

194
Q

describe the mutant lacking the C gene in the ABC flower model

A

lacks stamen and carpel but has extra petals and sepals

195
Q

describe the mutant lacking the B genes in the ABC flower model

A

lack stamen and petals but has extra sepals and carpels

196
Q

describe the mutant lacking the A genes in the ABC flower model

A

lacks petals and sepals but has extra carpel and stamen

197
Q

what is an apoprotein

A

photoreceptor protein

198
Q

what is a chromophore

A

a small organic molecule that detects and absorbs light, attached to the apoprotein

B (19 decks)

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