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