Post Midterm Flashcards

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1
Q

Plant Primary Macronutrients

A

Nitrogen (N)
Phosphorus (P)
Potassium (K)

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2
Q

Plant Secondary Macronutrients

A

Magnesium (Mg)
Sulfur (S)
Calcium (Ca)

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3
Q

Plant Micronutrients

A

Boron (B)
Chlorine (Cl)
Manganese (Mn)
Iron (Fe)
Nickel (Ni)
Copper (Cu)
Zinc (Zn)
Molybdenum (Mo)

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4
Q

Micronutrients

A

Normally found in small amounts

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5
Q

Concentrations of macronutrients range from

A

1000-450,000 ppm

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6
Q

Iron (Fe)- general info

A

Biologically relevant form in plants- Fe+2, Fe +3
Concentration in plant: Deficiency- <20, Normal- 20-1000, Toxicity- >2000

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7
Q

Copper (Cu)- General info

A

Biologically relevant form in plants- Cu+, Cu +2
Concentration in plant (ppm): Deficiency- <10, Normal- 10-25, Toxicity- >25

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8
Q

Zinc (Zn)- General info

A

Biologically relevant form in plants- Zn+2
Concentration in plant: Deficiency- <10, Normal- 10-120, Toxicity- >120

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9
Q

Manganese (Mn)- general info

A

Biologically relevant form in plants- Mn+2, Mn+3, Mn+4
Concentration in plant: Deficiency- <90, Normal- 90-200, Toxicity- >200

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10
Q

Molybdenum (Mo)- General info

A

Biologically relevant form in plants- Mo+4, Mo+6 (in moco or FeMoco)
Concentration in plant: Deficiency- <0.1, Normal- 0.1-90, Toxicity- >90

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11
Q

Boron -General info

A

Biologically relevant form in plants- B(OH)3
Concentration in plant: Deficiency- <10, Normal- 10-80, Toxicity- >80

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12
Q

Chloride- general info

A

Biologically relevant form in plants- Cl-
Concentration in plant: Deficiency- >100, Normal- 100-800, Toxicity- <800

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13
Q

Nickel (Ni)- General info

A

Biologically relevant form in plants- Ni+2
Concentration in plant: Deficiency- >0.05, Normal- 0.05- 10, Toxicity- <10

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14
Q

Micronutrients- general info

A

narrow optimal concentration range
most are immobile in plants

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15
Q

Micronutrients necessary for chlorophyll production

A

Iron (Fe) and Manganese (Mn)
Deficiency: poorly mobile elements causes interveinal chlorosis (yellowing)

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16
Q

Iron (Fe)

A

Abundant, important and largely insoluble
Fe largely oxidized and insoluble

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17
Q

Interveinal chlorosis

A

Yellowing
the characteristic symptom of iron deficiency

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18
Q

Strategies to improve nitrogen-use efficiency and decrease N pollution

A

Altering flux into amino acid pools or breeding strategies can enhance nitrogen use efficiency

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19
Q

Iron cells can be found in

A

Heme
Fe plays central role in electron transport (oxidation/reduction) processes

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20
Q

What is Chelation

A

The formation of bonds between two or more separate binding sites within a ligand and a single central atom
complex compounds consisting of A central metal atom attached to a ligand in a cyclic or ring structure “clamp”

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21
Q

DTPA chelates

A

Iron (Fe+3)

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22
Q

Organic acid (Citrate) binds to

A

Fe
Fe solubilization in soil
to maintain an accessible pool of Fe

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23
Q

Plant root exudate and microbial exudate

A

Increasing Pi availability

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24
Q

Rhizosphere

A

soil area around the plant root

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25
Q

yellow- stripe1 mutant

A

was identified from maize
A lack of chlorophyll
In the 1950s and 1960s, this phenotype is caused by iron deficiency
The transporter (YS) was cloned in 2001

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26
Q

Siderophores:

A

small metal-binding molecules
generated from bacteria

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27
Q

Phytosiderophores

A

generated from plants

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28
Q

Silicone

A

is beneficial to plants, especially under stress conditions

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29
Q

Iron uptake

A

Strategy I- dicots
Strategy II- monocots

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30
Q

Transport systems that operate across membranes

A

Symporter
Anitporter
Channels
H+ pump
ABC transporter

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31
Q

Flux (J) crossing biological membrane

A

Diffusion

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32
Q

Diffusion

A

Movement of individual molecules of a substance through a from an area of higher concentration to an area of lower concentration

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33
Q

Chemical potential

A

The sum of the concentration, electrical and hydrostatic potentials (under standard conditions)

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34
Q

Facilitated diffusion

A

involved in the movement of specific molecule (e.g. ions)
Needs specific channels or carrier proteins
needs no ATP energy for its transport

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35
Q

Facilitated diffusion of “i”

A

“i” interacts with a “molecule” in the membrane to permit its passive diffusion down its chemical potential gradient

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36
Q

Limited numbers of membrane transporters

A

membrane proteins are saturated at the high concentration

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37
Q

Glucose Permease

A

glucose transporter

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38
Q

Plastid glucose transporter

A

(pGluT; Glucose permease)
located in chloroplast inner envelope

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39
Q

Facilitated Diffusion of Charged Species in biological systems

A

Diffusion force drives in one direction, while electrostatic force drives in the opposite direction

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40
Q

Nernst potential

A

Electric field balances the concentration gradient in Activity of “i”

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41
Q

Active transport includes

A

ATPase, symporter and antiporter

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42
Q

Nitrogen that roots take up

A

They take up NO3- (Nitrate) or NH4+ (ammonium)

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43
Q

Phosphate transporters

A

PHT1 for phosphate (Pi) uptake and transport

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44
Q

H+-pumping ATPase:

A

Primary active transport system

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45
Q

Pumping protons out of the cell

A

Production of electric pH gradients

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46
Q

Proton (H+) electrochemical gradient

A

Driving processes of other transporters

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47
Q

Guard cells

A

Model systems for the study of membrane transport
opening and closing

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48
Q

Development of the plant vascular system

A

Coordination with the demands on the organism

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49
Q

Phloem and xylem

A

conducting elements in plants

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50
Q

Xylem

A

Root to shoot translocation

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51
Q

Phloem

A

Source to sink translocation

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52
Q

Source tissue

A

Exporting plant tissues or organs that produces photosynthate (e.g. sugars)- mature and photosynthetically active leave

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53
Q

Sink tissue

A

Non-photosynthetic developing organ or an organ that does not produce enough photosynthate

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54
Q

Leaf maturation

A

From leaf tip to the base

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55
Q

If plants are under K-deficient conditions

A

Substantial growth reduction
yellowing appears on the oldest leaves: K is mobile in plants
Brown necrotic lesions develop within the yellow parts and eventually spread to cover the entire leaf blade

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56
Q

Sieve tube

A

the functional units for long distance translocation of plant materials
stacked sieve elements

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57
Q

Sieve plate

A

a perforated wall between the sieve elements

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58
Q

Mature sieve elements contain

A
  1. Structural phloem specific proteins (P-proteins)
  2. Endoplasmic reticulum (ER)
  3. Mitochondria
  4. Sieve element plastids
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59
Q

Mature sieve elements DO NOT contain

A
  1. Nucleus
  2. Vacuole
  3. Golgi bodies
  4. Chloroplast (at the shoot)
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60
Q

P-proteins and Callose

A

protection mechanism in phloem

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61
Q

P protein

A

Sealing off damaged sieve elements by plugging up the sieve plate pores
quick plant response (short term solution)

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62
Q

Callose

A

B-(1,3)-glucan
seal off damaged sieve elements
long-term solution

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63
Q

Heterotrophic shoot

A

Assimilate “sink”

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64
Q

Autotrophic leaf

A

Assimilate source

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65
Q

Heterotrophic root

A

Assimilate “sink”

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66
Q

Sucrose loading into minor leaves

A

1) Symplasmic sucrose loading model
2) Apoplasmic sucrose loading model

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67
Q

Symplasmic sucrose loading model

A

sucrose moves through the plasmodesmata from the mesophyll cells to the phloem

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68
Q

Can all sugar forms move through the phloem?

A

“nonreducing sugars (less reactive) can be transported via the phloem”
Generally not reducing sugars

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69
Q

Glucose, Mannose and Fructose (reducing sugars) contain reducing groups (aldehyde and ketone group)

A

Chemically too reactive to be translocated through the phloem

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70
Q

Sucrose

A

the most common form of sugar
translocated through the phloem

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71
Q

Aphids feed directly from

A

phloem

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72
Q

What is being loaded/translocated through phloem?

A

water
photosynthate (raffinose group-sucrose):Sugars
Specific amino acids
Ions
Metabolites
Hormones (Auxin, gibberellic acid, etc.)
Proteins (role in signaling and SE maintenance)
RNA
(Information superhighway)

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73
Q

Chlorophyll

A

Reflection of green wave length (plants are green)

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74
Q

Endergonic (energy in) reaction

A

potential energy of substrate < product

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75
Q

Exergonic (energy out) reaction

A

Potential energy of substrate>product

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76
Q

Pyrenoid

A

carbon-fixing reactions take place

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77
Q

two types of photosynthesis

A

oxygenic photosyntehsis
anoxygenix photosynthesis

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78
Q

Oxygenic photosynthesis

A

Removal of electrons from H2O->release of O2
Reduction of CO2 to carbohydrate (3 carbon sugar)
Plants, algae and certain types of bacteria (cyanobacteria)

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79
Q

Anoxygenic Photosynthesis

A

Do Not extract electrons from water:

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80
Q

Plastids and chloroplasts

A

Essential organelles for most plant cells

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81
Q

Etioplast

A

dark grown photosynthetic tissue
no chlorophyll
Developed plastid from the proplastid when plants are grown in dark

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82
Q

Proplastid

A

undifferentiated
colorless
seeds, embryonic, meristems and reproductive tissues

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83
Q

Chromoplast

A

red and yellow pigment (carotenoids)
Flower (petal), fruit

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84
Q

Identity and abundance of plastids are controlled by

A

developmental and environmental cues

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85
Q

Light induces conversion from

A

Etioplast to chloroplast

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86
Q

Grana stacks in the thylakoids

A

Speciality of land plants

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87
Q

Chloroplast movement is

A

crucial for the plants living under a canopy

88
Q

Chlorophylls

A

the essential pigments that harvest the light energy and transduce it into chemical energy
all chlorophyll-based photosynthesis systems use chlorophyll a
are amphipathic molecules

89
Q

Chlorophyll b

A

land plants, green algae and cyanobacteria

90
Q

Carotenoids

A

all chlorophyll-based photosynthesis systems

91
Q

Phycoerthrin

A

non-green algae

92
Q

Phycocyanin

A

cyanobacteria

93
Q

Protoporphyrin IX

A

a precursor of Mg-containing chlorophyll and Fe-containing heme

94
Q

Light absorption is affected by

A

chemical structure of chlorophylls
noncovalent interaction of chlorophylls with proteins in photosynthetic membranes

95
Q

Functions of Carotenoids are

A

Accessory pigments
Protecting photosynthesizing organisms from destructive photooxidation (anti-oxidant)
Structural role in assembly of light harvesting complex

96
Q

Accessory pigments

A

Phycobilins

97
Q

Phycobilins

A

Named with the reason of their resemblance to bile pigments
They are: Linear tetrapyrroles, water soluble, accessory pigment with no associated metal

98
Q

Linear tetrapyrroles

A

derived from same biosynthetic pathway as chlorophyll and heme

99
Q

Amyloplast

A

lack pigments
lack elaborate inner membranes
Function: starch storage
Statoliths

100
Q

Statoliths

A

starch-filled amyloplasts function in gravity sensing

101
Q

Major factors to sustain plant life

A

Water, air and light

102
Q

Water

A

Solvent for enzymatic activity and formation of biological membrane

103
Q

Air

A

Basic elements (C,O,N)

104
Q

Light

A

Thermonuclear fusion generates ultimate form of energy in sun

105
Q

Photosynthetically available (Active) radiation

A

The portion of light that can be captured and used by photoautotrophs for photosynthesis

106
Q

Spectrum

A

the graph of absorbance versus wavelength

107
Q

The energy of the light particle (photon)

A

Light frequency

108
Q

Photosynthetic action spectrum

A

Magnitude of biological response to light (wavelength)
Rate of photosynthesis
A single wavelength of light shines on a plant

109
Q

Absorption spectrum

A

The amount of absorbed light by a molecules (pigment)
Functional wavelength of light in photosynthesis

110
Q

Comparison of action and absorption spectra

A

Effectiveness of energy transfer between pigments

111
Q

Why do pigments capture the light?

A

Get energy from the light

112
Q

Photoexcitation outcomes

A
  1. Heat
  2. Fluorescence
  3. Energy transfer
  4. Photochemistry
113
Q

Heat (photoexcitation outcome)

A

Thermal dissipation
Chlorophylls return to ground state

114
Q

Thermal Dissipation

A

Converting excitation energy to heat

115
Q

Fluorescence (photoexcitation outcome)

A

Immediate reemission of energy as a long wavelength

116
Q

Energy transfer (photoexcitation outcomes)

A

Excited pigment molecules (e.g. chlorophyll) transfers it energy to another molecule

117
Q

Photochemistry (photoexcitation outcome)

A

Energy of the excited state triggers a chemical reaction and becomes an e- donor
linkage of the excited e- donor to a proper e- acceptor
Transduction of chemical energy

118
Q

Ground state

A

Electrons occupy the lowest energy level before a photon of light strikes chlorophyll

119
Q

Excited state

A

Electrons gain energy when a photon hits chlorophyll

120
Q

Energy transfer during photosynthesis

A

Pure physical phenomenon
no chemical changes
Resonance energy transfer

121
Q

Resonance energy transfer

A

energy is transferred from pigment to pigment by resonance until it reaches the reaction center pigment

122
Q

Light harvesting complex (LHC, antenna complex)

A

Pigments molecules bounded to proteins

123
Q

Reaction center:

A

Special pair of chlorophyll a
electron acceptor

124
Q

Photosytem

A

Reaction center surrounded by several LHCs

125
Q

Energy funnel

A

from antenna system to the reaction center

126
Q

Cyanobacteria and red algae

A

peripheral antenna systems

127
Q

Plants and green algae

A

membrane-embedded light harvesting complexes (LHC)

128
Q

Oxygen evolving organisms have two photosytems

A

Photosystem I and II (PSI and PSII)

129
Q

Emerson enhancement effect

A

Two photosystems must operate to drive photosynthesis most effectively

130
Q

PSI and PSII are linked by

A

An electron transport chain

131
Q

Z-scheme

A

Cooperation of PSII and PSI in the transfer of electrons from water to NADP+

132
Q

Visible spectrum

A

(400 to 700 nm)
Main light to hit a leaf

133
Q

P700 is a very strong reductant

A

strong enough to donate electrons to NADP+

134
Q

P680+ is a very strong oxidant

A

strong enough to pull electrons from H2O

135
Q

The photosystems are embedded in

A

thylakoid membranes

136
Q

Plastoquinone (PQ)

A

small molecule and mobile electron carrier

137
Q

Cytochrome b6f (Cyt b6f)

A

Multiprotein membrane embedded complex

138
Q

Plastocyanin (PC)

A

small protein and mobile electron carrier

139
Q

Linear electron transport

A

PSII—-> Cyt b6f—-> PSI

140
Q

Electron transfer in PSII

A

(1) Light converts reaction center chlorophyll (P680) to excited form P680*
(2) Electron leaves P680*, forming P680+
(3) The electron is transferred to Pheophytin (Pheo), forming Pheo-
(4) Pheo- passes the electron to QA to produce QA-
(5) QA- passes the electron to QB to produce QB-

141
Q

Ferredoxin

A

is a soluble electron carrier to transfer electrons to NADP+

142
Q

ATP synthase

A

multi-subunit rotary machine
movement of protons from inside the lumen to the stroma across the thylakoid membrane
synthesis of ATP from ADP and Pi

143
Q

Photosynthesis

A

not a single reaction
photochemical reaction, electron transfer, biochemical reaction

144
Q

In the thylakoid membranes

A

the capture of light energy as ATP and reducing power, NADPH
(light reaction)

145
Q

In the chloroplast stroma

A

The transfer of energy and reducing power from ATP and NADPH to CO2
(Carbon-fixing reaction)

146
Q

Cyclic electron transport

A

flow of electron from PSI to Cyt b6f

147
Q

Linear electron transport

A

Flow of electrons from H2O to NADPH

148
Q

Water-water cycle

A

another form of electron transport
Product: ATP (no NADPH)
early time period after the transition from dark to light

149
Q

Pathways of electron transport

A

Linear electron transport
cyclic electron transport
water-water cycle

150
Q

Excess excitation energy can lead to

A

photo-oxidative damage

151
Q

Reactive oxygen species (ROS)

A

oxidative damage
reduced growth and yield losses

152
Q

Excess light energy is dissipated via

A

Non-photochemical quenching (NPQ)

153
Q

Non-photochemical quenching (NPQ)

A
  1. Energy dependent quenching (qE): the xanthophyll cycle
  2. State transition (qT): Conformational changes in LHCII
  3. Photoinhibition (qI): Light-induced reduction in quantum yield as a consequence of damage
154
Q

Energy- dependent quenching (qE)

A

Dominant form of NPQ
1. Lumen acidification activates Violaxanthin De-epoxidase (VDE)
2. Zeaxanthin leads to light energy dissipation by rearrangement of LHCII and reaction center II (RCII): decrease of energy transfer to RCII
3. The structural changes result in dissipation of light energy as heat

155
Q

Linear and cyclic electron transport in chloroplast

A

regulatory mechanism for control over stromal ATP/NADPH ratio
Maintenance of metabolic activities in plants

156
Q

Zeaxanthin and lutein

A

also have roles as antioxidants and in photoprotection to protect human eyes from phototoxic damage by accumulating in the macula

157
Q

State transition (qT):

A

Regulating the redox state of plastoquinone (PQ) pool

158
Q

LHCII phosphorylation

A

preventing the energy transfer to PSII

159
Q

Photoinhibition (qI)

A

Photodamage to PSII

160
Q

D1 protein

A

the key subunit of photosystem II (PSII)(Encoded by PsbA gene)
Multicomponent pigment- protein complex of oxygenic photosynthetic organisms
of PSII is susceptible to photodamage: photosynthesis is inhibited

161
Q

Herbicide

A

Strategies to target photosytems

162
Q

DCMU

A

a herbicide
blocking electron transport through PSII

163
Q

Paraquat

A

a herbicide
preventing reduction of NADP+ by accepting electrons in PSI

164
Q

Hexadecameric form of rubisco in plants

A

8 large subunits and 8 small subunits (L8S8)
Plants and most cyanobacteria (Form I)
Rubisco is found in a variety of forms (Form II, III and IV) in some bacteria, dinoflagellate algae and archaea

165
Q

The catalytic efficiency of Rubisco

A

very low

166
Q

Regulation of rubisco activity

A

the transcription, assembly and inhibition of rubisco

167
Q

CO2 fixation needs

A

3 ATP +2 NADPH

168
Q

Photorespiration is a multi-organellar process

A

Chloroplast, peroxisome and mitochondrion

169
Q

Peroxisome (called microbody)

A

1) Single membrane organelle with diameter of 0.5-1.5 mm
2) no inner membrane
3) No DNA or ribosomes in peroxisome
4) Inside a dense matrix: Urate oxidase crystalline core
5) Glyoxysome: Peroxisome in seeds
6)Peroxisomes tether to chloroplast

170
Q

Kranz anatomy in C4 plants

A

Bundle sheath cells form a ring around the vascular tissue, and mesophyll cells form a ring around bundle sheath cells

171
Q

Mesophyll cells

A

Chloroplast with grana

172
Q

Bundle sheath cells

A

Starch-rich chloroplast without grana

173
Q

Transporters and plasmodesmata

A

transport function of metabolites between bundle sheath and mesophyll cells

174
Q

Economically important C4 species in agriculture

A

monocot plants
Corn
Sugar cane
and sorghum

175
Q

In hot and dry weather

A

Stomata closed: preventing water evaporation and CO2 uptake
The concentration of CO2 is low
HCO3- is generated from CO2 by Carbonic anhydrase
Phosphoenolpyruvate carboxylase fixes HCO3-

176
Q

Crassulacean acid metabolism (CAM)

A

Carbon fixation at night

177
Q

CAM plants

A

Cactus and succulents

178
Q

CAM plants are economically important in agriculture

A

Vanilla orchid
Orchid plant
Agave grown for tequila
Pineapple
Aloe vera

179
Q

PEP carboxylase fixes HCO3-

A

at night

180
Q

Limiting factors for the rate of photosynthesis

A

Light intensity
CO2 concentration
Temperature

181
Q

Light intensity

A

decrease of photosynthesis rate in low light intensity
No effect on the rate of photosynthesis above the optimum conditions

182
Q

CO2 concentration

A

Decrease of photosynthesis rate in low CO2 concentration
No effect on the rate of photosynthesis above the optimum condition

183
Q

Temperature

A

lower photosynthesis rate above or below the optimum temperature

184
Q

Chloroplast movement

A

is crucial for the plants living under a canopy

185
Q

Shade leaf

A

can capture and use radiation in Far-red and infra-red regions of the light spectrum

186
Q

How to monitor light reactions

A

O2 production and CO2 consumption

187
Q

Saturation of Rubisco activity for carboxylation=

A

excess light

188
Q

Photosynthetic CO2 assimilation=

A

amount of CO2 generated by respiration

189
Q

PAR (photosynthetically active radiation)=

A

light intensity

190
Q

The light response curve and a quantum efficiency

A

Light reaction of photosynthesis (quantum yield

191
Q

Quantum

A

amount of energy in each photon

192
Q

At low light intesities, the relationship between net photosynthesis and light intensity is

A

linear

193
Q

At low light intensities, there is

A

a negative value of net photosynthesis
and light is limited for photosynthesis

194
Q

At the light saturation point, photosynthetic reaction rate is determined by

A

light- independent reactions (carbon fixation)

195
Q

In the dark

A

CO2 production is greater than CO2 consumption

196
Q

What factors influence quantum yield?

A

Light absorbance
Balance in excitation energy between PSI and PSII
Temperature

197
Q

Quantum yield determines the

A

efficiency of photochemistry

198
Q

Dynamic photoinhibition

A

under moderate excess light
Short-term reversible and regulatory process
maximum photosynthetic rate remains unchanged

199
Q

Chronic photoinhibition

A

under high excess light
long-term reversible process
Photodamage
photosynthetic rate decrease

200
Q

Photodamage

A

mechanism associated with damage and replacement of D1 protein in PSII

201
Q

Transport of CO2 from the atmosphere into the chloroplast

A

Diffusion

202
Q

Diffusion path of CO2 into the chloroplast

A

Gaseous phase

203
Q

The liquid phase of chloroplasts, stroma

A

CO2 solubilization and Carbon fixation

204
Q

In air of high relative humidity

A

the diffusion gradient of water vapor for driving water loss is about 50 times larger than the gradient of CO2 uptake

205
Q

A decrease in stomatal resistance through the opening of stomata facilitates higher CO2 uptake

A

but unavoidably accompanied by substantial water loss

206
Q

C4 plants use CO2 concentration mechanism

A

Carbon-fixation in C4 plants saturates at lower-than ambient CO2 levels

207
Q

Carbon assimilation of C3 plants increases

A

with increasing CO2 concentration

208
Q

C3 plants are expected to benefit more than C4 or CAM plants

A

from elevated CO2

209
Q

Plants grown in high CO2 environment contain

A

more total non-structural carbohydrates (e.g. starch, sucrose)

210
Q

Elevated CO2 reduces

A

overall mineral concentrations, such as contents of N (protein) and other macro and micro nutrients essential for human health

211
Q

Free air CO2 enrichment (FACE) studies

A

to test the plant response to elevated CO2 concentration

212
Q

Plants can be exposed to elevated CO2 by

A

pumping CO2 gas into the field

213
Q

Drought

A

Stomata closed- decrease of CO2 uptake- lowering Ci- decrease of carbon assimilation

214
Q

Heat results

A

in deactivating rubisco

215
Q

High CO2 environment

A

can enhance plant growth and flowering as well as senescence

216
Q

Water-use efficiency

A

can be affected by elevated CO2 levels