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Flashcards in Class 5 Deck (122):
1

photosynthesis powers the cellular processes in the plant and downstream, the main -- of organisms and ecological processes

energy source

2

ligher reactions are also called the -- reactions

thylakoid

3

carbon (fixation) reactions are also called the -- reactions

dark

4

the bulk of photosynthesis takes place in the leaf -- which has cells with many chloroplasts

mesophyll

5

chloroplasts have high concentration of light-absorbing -- pigments called chlorophylls

green

6

light reactions occur in the --

internal membranes (thylakoid)

7

carbon reactions occur in the -- of the chloroplast, the aqueous region surrounding the thylakoids

stroma

8

light reactions lead to the splitting of --

water

9

light reactions produce -- and -- (reducing equivalents and energy) to be provided to the carbon reactions

ATP and NADPH

10

light is an -- wave and many kinds of light exist = many wavelengths (or frequencies)

electromagnetic

11

light is also a particle so it contains --

energy (i.e. impact)

12

sunlight is a stream of -- of different frequencies

photons

13

plants can only use a narrow range of wavelengths for photosynthesis, the same range as the human eye,

visible spectrum, 400-700 nm

14

an -- of a substance quantifies its ability to take up light across the spectrum

absorption spectrum

15

absorption spectrum plots a substance's absorption of light against -- of light

wavelength

16

absorption of light energy by pigment molecules takes place when the photon causes an electron to move to a higher energy state; the molecule becomes --

excited

17

as a chlorophyll molecule returns to its less excited state, it releases the energy by emitting --, energy transfer, or photochemistry

heat, fluorescence,

18

fluorescence involves -- a photon of lower energy (longer wavelength)

re-emitting

19

energy transfer causes the -- of another pigment

excitation

20

photochemistry causes -- to occur

chemical reactions

21

photosynthetic pigments include chlorophylls (and -- in certain bacteria), and carotenoids and other accessory pigments

bacteriochlorophylls

22

photosynthetic pigments are rich in -- which stabilize the excited state

conjugated double bonds

23

chlorophyll a and chlorophyll b are made up of a complex ring structure called -- (similar to in hemoglobin)

haem group

24

a harm group contains a -- atom bonded to nitrogen

Mg

25

a harm group contains a long -- that holds the pigment anchored to a protein or membrane

hydrocarbon tail

26

carotenoids are linear molecules which give a -- color

orange

27

carotenoids are intimately associated with the -- and with photosynthetic proteins

thylakoid membrane

28

light absorbed by the carotenoids is transferred to chlorophyll for photosynthesis and thus carotenoids are --

accessory pigments

29

carotenoids also help protect from --

excess light damage

30

plots of the response of a system (i.e. products generated in a reaction) against light wavelength (used to study light-driven reactions)

action spectra

31

an action spectrum will show what -- of light can cause the reaction to proceed

wavelengths

32

light absorption in the chloroplasts is primarily done by chlorophyll in the --

antenna complex (light-harvesting antenna)

33

antenna complex transfers the absorbed energy to chlorophyll in the --

reaction centers

34

because bright light is -- even without an antenna, many reaction centers would be activated only intermittently

dilute

35

having -- of the chlorophyll in the antenna allows the reaction centers to run continuously

> 95%

36

red drop effect showed that only -- light was inefficient in driving photosynthesis despite high absorption of this wavelength

far-red

37

enhancement effect showed a major enhancement of photosynthesis when -- together were supplied, relative to when either were supplied alone

red and far-red

38

photosystem -- preferentially absorbs far-red light

I

39

photosystem -- preferentially absorbs red light and is driven very poorly by far-red light

II

40

Z scheme is constituted of two photosystems each with its own antenna pigments and photochemical reaction center linked by an --

electron transport chain

41

stacked thylakoids

grana lamellae

42

unstacked thylakoids

stroma lamellae

43

T/F: chloroplast is bounded by two lipid bilayer membranes, the inner and outer envelope

true

44

chloroplast contains its own --

DNA, RNA, and ribosomes

45

some chloroplast proteins are produced within the chloroplast itself whereas others are encoded by nuclear DNA and produced in the -- and imported into the chloroplast

cytoplasm

46

T/F: some chloroplastic enzymes are composed of protein sub unites encoded from both nuclear and chloroplast DNA

true

47

proteins embedded in the thylakoid membranes, via hydrophobic amino acids, with regions extending into surrounding aqueous medium are called

integral membrane proteins

48

reaction centers, the antenna pigment/protein complexes and most of the -- proteins are integral membrane proteins

electron carrier

49

photosynthetic pigments are associated in a -- but highly specific way with proteins forming pigment-protein complexes

noncovalent

50

pigment-protein complexes are organized within the -- to optimize energy transfer in antenna complexes and electron transfer in and between reaction centers

membrane

51

photosystem I and Ii are -- in the thylakoid membrane

spatially separated

52

PSII located in

grana lamellae

53

PSI located in

stroma lamellae

54

ATP synthase enzyme is located in

stroma lamellae

55

-- that connects the two photosystems is evenly distributed between the two photosystems

cytochrome -b6f complex

56

diffusible electron carriers -- and -- deliver the electrons between photosystems

plastocyanin and plastoquinone

57

plants usually have an excess of PSII to PSI usually a ratio of about --

1.5 : 1

58

the antenna system delivers energy efficiently to the --

reaction centers

59

there are -- chlorophylls per reaction centers in higher plants

200-300

60

diverse antenna pigments are involved, all associated with the --

thylakoid membrane

61

energy is transferred from the antenna to the reaction center by -- resonance energy transfer

fluorescence resonance

62

the energy transfer to the reaction center occurs by a -- process such as the transfer of energy between tuning forks

nonradiative

63

the sequence of pigments within the antenna shifts progressively toward --

longer red wavelengths (lower energy)

64

some -- is dissipated during energy transfer

heat

65

since heat is lost, energy at the outside of the antenna is -- than near the reaction center; this keeps the energy transfer moving one way

higher

66

most abundant antenna proteins

light-harvesting complex II proteins

67

light-harvesting complex II proteins bind -- chlorophyll molecules

14

68

photons excite the chlorophyll of the reaction centers, -- an electron

ejecting

69

after excitation, the ejected electron then passes through a series of electron carriers, eventually reducing -- and generates ATP

reducing NADP+

70

photosystem II oxidizes water to oxygen in the --

thylakoid lumen

71

when PSII oxidizes water it releases -- into the lumen

protons

72

when PSII oxidizes water it passes electron to the plastoquinone, forming --

plastohydroquinone

73

-- oxidizes plastohydroquinone

cytochrome b6f

74

cytochrome b6f delivers electrons to --

plastocyanin

75

PSI oxidizes --

plastocyanin

76

PSI passes electrons to -- which reduces NADP+ generating NADPH

ferredoxin

77

ATP synthase produces ATP as protons diffuse through it from -- to --

lumen to stroma

78

light excites a reaction center chlorophyll by direct absorption or more frequently via -- from an antenna pigment

energy transfer

79

the absorbed photon causes an electron -- in the reaction center

rearrangement

80

P680

PSII

81

P700

PSI

82

PS II has its electron supplied by a

donor Yz

83

donor Yz has its electron supplied by the --, an enzyme that splits (oxidizes) water

oxygen-evolving complex

84

Mn is an essential --

co-factor

85

from the cytochrome b6f complex, one electron moves linearly toward --

plastocyanin (PC)

86

from the cytochrome b6f complex, one electron goes through a --, which effectively pumps more protons into the thylakoid lumen

cyclic process

87

plastoquinone distributed on the

grana thylakoids

88

plastocyanin distributed on the

stroma thylakoids

89

cytochrome b6f complex is -- distributed between the grana and stroma thylakoids

equally

90

Q, PC, and cytochrome b6f are large complexes that are embedded in the --

membrane

91

Q and PC are --, relatively small molecules

mobile

92

Q is -- soluble moving in the membrane

lipid

93

PC is -- soluble moving in the thylakoid lumen

water

94

PS I has its electrons resupplied by --

PC

95

a core -- is an integral part of the reaction center

core chlorophyll

96

under certain conditions, cyclic electron flow occurs, in which -- passes electrons back to the cytochrome b6f complex, which results in more protons pumped into the lumen

PS I

97

some herbicides -- electron transport

block

98

-- blocks reduction of the plastoquinone acceptor

DCMU

99

-- competes with ferredoxin acceptors of PS I

paraquat

100

ATP synthesis during the light reactions is known as --

photophosphorylation

101

photophosphorylation occur via -- mechanism

chemiosmotic

102

the accumulation of H+ in the lumen (i.e. acidification of the lumen) creates a chemical and electric gradient known as the -- force

proton-motive

103

main light harvesting pigments for photosynthesis

chlorophylls

104

integral membrane proteins are -- arranged in the membranes (they have a unique orientation)

asymmetrically

105

every year about -- tons of CO2 are converted to biomass via photosynthesis

200 billion

106

starch

storage

107

sucrose

transport of energy

108

sucrose is a disaccharide composed of

fructose and glucose

109

generation of UDP glucose requires

UTP

110

starch is a -- of glucose

polymer

111

generation of ADP-glucose requires

ATP

112

during the day, the -- will drive the synthesis and storage of starch

accumulation of sucrose

113

at night, starch is broken down into sugars in the chloroplasts and sugars are exported out of the chloroplast for --

sucrose production

114

these of ATP as an activator of starch synthesis and UTP as an activator of sucrose synthesis keeps these reactions

compartmentalized

115

starch and sucrose synthesis can be activated and deactivated --

separately

116

during the -- both sucrose and starch synthesis can occur

day

117

which synthesis occurs most depends on the -- from the cell due to phloem transport

sucrose depleted

118

buildup of -- in the cell will drive starch production

sucrose

119

during night, -- synthesis is inhibited

starch

120

during --, starch breakdown occurs and sucrose production continues

night

121

many cells grow at --

night

122

growing cells utilize sugars derived from sucrose in the --

phloem