Photosynthesis in Higher Plants Flashcards
1
Q
Green plants make their own food by the process of
A
Photosynthesis
2
Q
A physicochemical process by which plants use light energy to drive the synthesis of organic compounds is called
A
Photosynthesis
3
Q
The process which is primary source of all food on earth is
A
Photosynthesis
4
Q
Apart from light and carbon dioxide, which pigment is essential for photosynthesis to occur?
A
Chlorophyll
5
Q
A KOH soaked cotton will absorb gaseous _____________
A
Carbon dioxide
6
Q
The scientist who in 1770 performed a series of experiments that revealed the essential role of air in the growth of green plants was
A
Joseph Priestley
7
Q
Oxygen in 1774 was discovered by
A
Joseph Priestley
8
Q
Who showed that sunlight is essential to the plant process?
A
Jan Ingenhousz
9
Q
Ingenhousz in his experiment with an aquatic plant showed some bubbles formed around green parts of plant to be composed of
A
Oxygen
10
Q
Only the green part of plants could release oxygen was proved by
A
Jan Ingenhousz
11
Q
The scientist who provided evidence for production of glucose when plants grow was
A
Julius von Sachs
12
Q
The scientist behind the finding that the glucose is made in green parts of plant and is usually stored as starch was
A
Julius von Sachs
13
Q
Engelmann observed that bacteria accumulated mainly in region of ___________ and __________ light of split spectrum from his experiments on Cladophora
A
Blue and red
14
Q
The first action spectrum of photosynthesis was described by
A
T. W. Engelmann
15
Q
Cornelius van Niel based on his studies of purple and green bacteria, demonstrated that photosynthesis is essentially a _____________ reaction
A
Light dependent
16
Q
Cornelius in his experiment demonstrated that in a light-dependent reaction, hydrogen from a suitable oxidisable compound reduces carbon dioxide to __________
A
Carbohydrates
17
Q
Hydrogen donor for purple and green sulphur bacteria is
A
H2S
18
Q
In purple and green sulphur bacteria, oxidation product is
A
Sulphur or sulphate
19
Q
Cornelius inferred that oxygen evolved by green plant comes from ___________
A
Water
20
Q
The cells of leaves having large number of chloroplasts are
A
Mesophyll cells
21
Q
Within the chloroplast there is membranous system consisting of ________, the _________, and the ________ stroma.
A
Grana, stroma lamellae, matrix
22
Q
Synthesis of sugar through enzyme reactions and its conversion to starch occurs in
A
Stroma
23
Q
Reactions occuring in membrane system are called ___________ reactions
A
Light
24
Q
Carbon reactions occuring in stroma are called
A
Dark reactions
25
Dark reactions are not directly dependent on light but on the products of light reactions like _______ and _______
ATP and NADPH
26
Separation of leaf pigments of any green plant can be done by which basic technique?
Paper chromatography
27
The four pigments giving colour to leaves are
Chlorophyll a, chlorophyll b, xanthophyll, carotenoids
28
The pigment which is bright or blue green in chromatogram is
Chlorophyll a
29
Colour of chlorophyll b in chromatogram is
Yellow green
30
Xanthophylls appear ____________ in chromatogram
Yellow
31
The colour range of carotenoids in chromatogram is
Yellow to yellow-orange
32
The substances that have an ability to absorb light, at specific wavelengths are called
Pigments
33
Maximum absorption of chlorophyll a occurs in ______and _______ regions
Blue, red
34
The chief pigment associated with photosynthesis is
Chlorophyll a
35
The three accessory pigments for light absorption in plants are
Chlorophyll b, xanthophylls and carotenoids
36
The function of accessory pigments is to absorb light and transfer the energy to __________
Chlorophyll a
37
Accessory pigments prevent __________________ of chlorophyll a
Photo-oxidation
38
Light absorption, water splitting, oxygen release, and the formation of high energy chemical intermediates are included in the process of _____________
Light reaction
39
High energy chemical intermediates formed during light reaction are
ATP and NADPH
40
The pigments are organised into two photochemical light harvesting complexes namely
PSI and PSII
41
In LHC, hundreds of pigments are bound to ________
Proteins
42
Each photosystem has all pigments except one molecule of _________ pigment.
Chlorophyll a
43
Each photosystem has all the pigments (except one molecule of chlorophyll a) forming a light harvesting system also called _______
antennae
44
Single chlorophyll a molecules forms
Reaction centre
45
n PSI, reaction centre chlorophyll a has an absorption peak at _______
700 nm
46
In PSII, reaction centre chlorophyll a has an absorption peak at _____
680 nm
47
PSI and PSII are also called _______ and ________ respectively
P700 and P680
48
In PSII, reaction centre chlorophyll a absorbs 680 nm wavelength of ______ light
Red
49
The excited electrons are picked up by an electron acceptor which passes them to _______________ consisting of cytochromes.
Electron transport system
50
The movement of electrons in ETS is downhill in terms of which scale?
Redox potential scale
51
Electrons from ETS are passed on to pigments of which photosystem?
PSI
52
Electrons in reaction centre of PSI are excited when they receive red light of wavelength
700 nm
53
Electrons excited in PSI at 700 nm are transferred to another acceptor molecule that has higher __________
Redox potential
54
The whole scheme of transfer of electrons is referred to
Z scheme
55
Splitting of water is associated with which photosystem?
PS II
56
Electrons to replace those electrons removed from PSI are provided by
PSII
57
Electrons moved from PSII are replaced by electrons from ________
Splitting of water
58
PSII is located on
Inner side of thylakoid membrane
59
The process by which ATP is synthesised by cells is called
Phosphorylation
60
Phosphorylation occurs in which organelles?
Mitochondria and chloroplast
61
Synthesis of ATP from ADP and inorganic phosphate in the presence of light is called
Photophosphorylation
62
When the two photosystems work in a series, first PS II and then the PS I, then the process is called
Non-cyclic photophosphorylation
63
The products synthesised by non-cyclic photophosphorylation are
ATP and NADPH + H+
64
When only PSI is functional, phosphorylation occurs due to
Cyclic flow of electrons
65
Usually only PSI is functional in which part of chloroplast?
Stroma lamellae
66
Membrane of stroma lamellae lack PSII as well as enzyme -
NADP reductase
67
In stroma lamellae, excited electron instead of passing on to NADP+ but is cycled back to
PSI complex
68
Cyclic flow results only in synthesis of ________
ATP
69
Cyclic photophosphorylation occurs only when light of wavelength beyond ______ nm are available for excitation.
680
70
In photosynthesis, ATP synthesis is linked to development of ___________ across a membrane
Proton gradient
71
ATP synthesis during photosynthesis occurs in the membrane of ______
Thylakoid
72
During photosynthesis, protons accumulate in the lumen of _________
Thylakoid
73
During photosynthesis, where does splitting of water molecules occur?
Inner side of thylakoid membrane
74
Protons produced by splitting of water molecule are accumulated in ____________
Lumen of thylakoids
75
During ATP synthesis, primary acceptor of electron transfers its electron to ___________
H carrier
76
NADP reductase enzyme is located on the ____________
Stroma side of membrane
77
Within chloroplast, protons in stroma decrease in number with decrease in pH of _________
Lumen
78
Breakdown of proton gradient is crucial for synthesis of ____
ATP
79
CF0 of ATP synthase is embedded in _________
Thylakoid membrane
80
The part of ATP synthase that carries out facilitated diffusion of protons across membrane is
CF0
81
The portion of ATP synthase that protrudes on outer surface of thylakoid membrane on side towards stroma is
CF1
82
Conformational change in _____ particle of ATP synthase induces synthesis of ATP
CF1
83
Chemiosmosis requires a membrane, proton pump, ATP synthase and ___________
Proton gradient
84
Diffusion of protons across membrane creates enough energy to activate ___________
ATP synthase
85
Products of light reaction are -
ATP, NADPH and O2
86
ATP and NADPH are used to drive processes leading to synthesis of ___________
Sugars
87
Diffusion of O2 out of chloroplast and use of ATP and NADPH to synthesise sugars are included in _______________ phase of photosynthesis
Biosynthetic
88
Biosynthetic phase of photosynthesis is dependent on
Products of light reaction
89
_____________ discovered that the first CO2 fixation product was 3 carbon organic acid while working on algal photosynthesis
Melvin Calvin
90
The first stable product of Calvin cycle was identified as
3-phosphoglyceric acid
91
The 4 carbon product found as first stable product of CO2 fixation in some plants was
Oxaloacetic acid
92
The plants in which first stable product during CO2 fixation was PGA were called
C3 plants
93
The pathway in which first stable product was found to be oxaloacetic acid was called
Hatch and Slack Pathway/ C4 pathway
94
The primary acceptor of CO2 is a _____ carbon compound in C3 cycle.
5
95
The primary acceptor of CO2 that was a 5-carbon ketose sugar was found to be
Ribulose bisphosphate
96
The photosynthetic pathway that occur in all types of plants is
C3
97
The three main stages of Calvin cycle are
Carboxylation, reduction and regeneration
98
The fixation of CO2 into a stable organic intermediate is called
Carboxylation
99
In C3 cycle during carboxylation, CO2 is utilised for carboxylation of _________
RuBP
100
The enzyme catalysing the reaction of carboxylation in calvin cycle is
RuBP carboxylase
101
RuBP carboxylase catalyses the reaction of conversion of CO2 to _______
PGA
102
Enzyme involved in carboxylation is called
RuBisCO
103
During reduction, series of reactions lead to the formation of ________
Glucose
104
During reduction in C3 cycle, how many molecules of ATP are required?
2
105
2 ATPs during reduction in C3 cycle are required for ________
Phosphorylation
106
Synthesis of one molecule of glucose requires ______ turns of C3 cycle
Six
107
The number of CO2 molecules fixed to form a molecule of glucose are
Six
108
During regeneration phase of C3 cycle, the molecule that needs to get regenerated is
RuBP
109
Regeneration of RuBP requires how many ATPs for phosphorylation?
One
110
For every CO2 molecule entering C3 cycle, _____ and ______ molecules of ATP and NADPH are required, respectively
3 and 2
111
Six CO2 molecule form one molecule of glucose in C3 cycle is by utilising ____ ATPs.
18
112
A molecule of glucose is synthesised by utilising ____ NADPHs
12
113
CO2 fixation in plants adapted to dry tropical regions occur by ___________
C4 cycle
114
C4 plants use _____ pathway as the main biosynthetic pathway
C3
115
Special leaf anatomy, tolerance to high temperatures, lack photorespiration are characteristic features of _______ plants
C4
116
C4 plants which show response to high light intensities and have greater productivity biomass have their first CO2 fixation product as ____
OAA
117
C4 plants have special leaf anatomy called
Kranz anatomy
118
The large cells around vascular bundles of C4 plants are called
Bundle sheath cells
119
Bundle sheath cells are characterized by having large number of
Chloroplasts
120
The cells in C4 plants which are imperveous to gaseous exchange and have no intercellular space are called
Bundle sheath cells
121
Name two C4 plants
Maize and sorghum
122
The primary acceptor of CO2 in Hatch and Slack pathway is
Phosphoenolpyruvate
123
PEP in C4 plants is present in
Mesophyll cells
124
Enzyme responsible for fixation of CO2 in C4 cycle is
PEPcase or PEP carboxylase
125
OAA is formed in
Mesophyll cells
126
The enzyme which is not present in mesophyll cells of C4 plants is
RuBisCO
127
OAA before getting transported to bundle sheath cells gets converted into
Aspartic or malic acid
128
C4 acids in C4 plants are broken down in ________________ to release CO2 and 3C compound
Bundle sheath cells
129
In C4 cycle, the 3-carbon molecule is transported back to the mesophyll where it
is converted to _______ again, thus, completing the cycle.
PEP
130
Photosynthetic pathway which is common to all plants is ______
C3
131
Bundle sheath cells of C4 plants are rich in enzyme -
RuBisCO
132
Bundle sheath cells lack enzyme ________ which is present in mesophyll cells
PEPcase or PEP carboxylase
133
Calvin pathway in C3 plants occur in __________ while in C4 plants, it takes place in _______
Mesophyll cells, bundle sheath cells
134
During carboxylation, RuBP combines with CO2 to form 2 molecules of _____
3-PGA
135
The most abundant enzyme in the world is _______
RuBisCO
136
RuBisCO has active sites both for _________ and _______
CO2 and O2
137
RuBisCO has greater affinity for _____ when CO2-O2 ratio is equal
CO2
138
What determines binding of CO2/O2 to RuBisCO?
Relative concentration of CO2/O2
139
O2 binds to RuBisCO to produce?
Phosphoglycerate and phosphoglycolate
140
Photorespiration is limited to ____ plants
C3
141
When O2 binds to RuBisCO instead of CO2, one molecule each of phosphoglycerate and phosphoglycolate are formed, this process is known as
Photorespiration
142
The process that neither synthesizes sugar nor ATP and releases CO2 on expense of ATP is
Photorespiration
143
C4 plants do not undergo photorespiration as they possess a mechanism that increases concentration of ____ at enzyme site
CO2
144
If a chemical process is affected by more than one factor, then its rate will be determined by the factor which is nearest to its minimal value it is the factor which directly affects the process if its quantity is changed, is known as
Law of Limiting Factors
145
Law of Limiting factors was given by
Blackman
146
Incident light and CO2 fixation rates at low intensity have _________ relationship
Linear
147
Light saturation in plants occur at ___% of the full sunlight
10
148
Increase in light beyond a point causes breakdown of ________
Chlorophyll
149
The concentration of CO2 is very low in the atmosphere (between ____ and ____ per cent).
0.03 to 0.04%
150
CO2 levels beyond _____% is damaging
0.05
151
C4 plants show CO2 saturation at
360 µl/L
152
C3 plants show CO2 saturation beyond ___
450 µl/L
153
Temperature has more effect on _________ reactions
Dark
154
____ plants respond to higher temperature
C4
155
Optimum temperature of a plant depends on its ________
Habitat
156
Water stress causes the _______ to close hence reducing the CO2 availability.
stomata
157
Water stress leads to ________ of leaves
Wilting
