Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology (NCERT) - Class XI > XI Chap 13 Photosynthesis Higher Plants > Flashcards

XI Chap 13 Photosynthesis Higher Plants Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is photosynthesis?

A

physico-chemical process;
plants use light energy;
synthesis of organic compounds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Photosynthesis is important for what 2 reasons?

A
  1. primary source of all food on earth

2. oxygen into the atmosphere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

__________ in ______ performed a series of experiments that revealed the role of air in the growth of green plants

A

Joseph Priestley in 1770

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

_______ discovered oxygen in _____

A

Joseph Priestley in 1774

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

________ used the same setup used in Priestley but modified it placing it once in dark and once in sunlight to show that ________

A

Jan Ingenhousz, sunlight is essential to plant process that purifies air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

________ in an experiment with an aquatic plant showed that in bright sunlight, small ____ were formed around green parts of plants which did not form in dark

A

Jan Ingenhouse, bubbles of oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

It wasn’t until ____ that _______ provided evidence for production of glucose when plants grow.

A

1854, Julius von Sachs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What were the experiments done by TW Engelmann?

A

Described the action spectrum of photosynthesis.

Split light using a prism -> placed a green alga Cladophora in suspension of aerobic bacteria -> observed that bacteria accumulated in blue and red light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

In what years was T W Engelmann alive?

A

1843 - 1909

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

By the middle of _______ century, key features of plant photosynthesis were known (i.e plants use light to make carbohydrates from CO2 and water).

A

19th

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What was microbiologist Cornelius van Niel’s contribution to study of photosynthesis?

A

studies of purple and green bacteria,

showed that hydrogen from a suitable oxidisable compound reduces CO2 to carbohydrates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

In green plants ______ is the hydrogen donor oxidized to O2

A

H2O

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Some organisms do not release O2 during photosynthesis. T or F?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

When H2S is the hydrogen donor for purple and green bacteria, the oxidation product is _____ or _____

A

sulphur or sulphate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How do we know that O2 evolved by green plants comes from H2O and not CO2?

A

Experiments with H2S and purple/green bacteria that produced sulphur/sulphate and not oxygen (later proved by using radioisotopic techniques)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the equation that represents photosynthesis accurately?

A

6CO2 + 12H2O —– (light) —-> C6H12O6 + 6H2O + 6O2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Photosynthesis is a single-step process represented by one equation. T or F?

A

False, multi-step process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

________ cells in the leaves have a large number of chloroplast

A

Mesophyll

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why do chloroplasts align themselves to the walls of the mesophyll cells?

A

they get optimum quantity of incident light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

There is clear division of labour in chloroplast. T or F?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Membrane system is responsible for trapping light energy in chloroplasts and for the synthesis of ATP and NADPH. T or F?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

In stroma, enzymatic reactions synthesize ______ which in turn forms _____

A

sugar, starch

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are light and dark reactions?

A

Light - directly light driven

Dark - not directly light-driven but depend on products of light reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Light reactions are aka _________, dark reactions are aka _________

A

photochemical reactions,

carbon reactions / biosynthetic phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Synthesis of ATP and NADPH - is it a light or dark reaction?

A

Light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Synthesis of sugar and starch - light or dark reactions?

A

Dark

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Dark reactions occur in darkness and are not light-dependent. T or F?

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

You can separate leaf pigments of any green plant through ________ process

A

paper chromatography

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Color in leaves are due to how many pigments? What are they and their colors on chromatogram?

A

4

Chlorophyll a - bright or blue green
Chlorophyll b - yellow green
Xanthophylls - yellow
Carotenoids - yellow to yellow orange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

_______ are substances that have the ability to absorb light at specific wavelengths.

A

Pigments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

_________ is the chief pigment associated with photosynthesis

A

Chlorophyll a

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Most of photosynthesis takes place in ___ and ____ regions of the spectrum

A

blue and red

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

No photosynthesis takes place outside the blue and red regions of the spectrum. T or F?

A

False, some does

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What are the pigments responsible for trapping light other than chlorophyll?

A

Thylakoid / accessory pigments: chlorophyll b, xanthophylls, cartenoids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Accessory pigments transfer the energy from light absorbed to chlorophyll a. T or F?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Accessory pigments enable a wider range of wavelength of incoming light to be utilized and protect chlorophyll a from ________

A

photo-oxidation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is the photochemical phase?

A

Light reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What does the photochemical phase include?

A

Light absorption,
water splitting,
oxygen release and
formation of ATP and NADPH

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What are the protein complexes involved in photochemical phase?

A

2 discrete photochemical light harvesting complexes, one in Photosystem I (PS I) and one in Photosystem II (PS II)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

PS I and II are numbered according to the order….?

A

in which they were discovered NOT in which they function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What are LHC made up of?

A

hundreds of pigment molecules bound to proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Each photosystem has all the pigments except ____________

A

one molecule of chlorophyll a

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What are antenna

A

light harvesting system formed by all the pigments in the photosystem

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What role do LHC play?

A

make photosystem more efficient, pigments absorb different wavelengths of light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What is a reaction centre?

A

single chlorophyll a molecule, different in both photosystems

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Absorption peaks for reaction centres for PS I and PS II?

A

PS I - absorption peak at 700nm (P700)

PS II - absorption peak at 680nm (P680)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

In PS II, reaction centre absorbs 680nm wavelength of ____ light causing electrons to become excited and ________

A

red light,

jump into an orbit farther away from the atomic nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

Excited electrons in PS II are picked up by __________ which passes them on to an electrons transport

A

electron acceptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Electron transfer system consists of ________

A

cytochromes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

Movement of electrons in transport system is ________ (uphill or downhill) in terms of an oxidation-reduction or redox potential scale.

A

Downhill

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

Electrons are used up as they pass through the electron transport chain. T or F?

A

False, they’re passed on to pigments of PS I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

Electrons in PS I are excited when they receive _____ light of wavelength _____ and are transferred to ______ that has _____ (lesser/greater) redox potential than PS II

A

red, 700nm, another acceptor molecule, greater

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

From the acceptor associated with PS I, electrons are moved _______ (uphill/downhill) to a molecule of _______

A

downhill,

energy-rich NADP+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Addition of electrons to NADP+ _____________ (oxidises/reduces) it to _____________

A

reduces

NADPH + H+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What is Z scheme?

A

Transfer of electrons starting from PS II - uphill to the acceptor - down the electron transport chain to PS I - excitation of electrons - transfer to another acceptor - finally down hill to NADP+ reducing it to NADPH + H+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Z-shape for Z-scheme is formed when all the carriers are placed in a sequence on __________ scale

A

redox potential scale

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

How does PS II supply electrons continuously?

A

Splitting of water, water is split into 2H+ , O and electrons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Splitting of water creates ______ one of the net products of photosynthesis

A

oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Electrons needed to replace those removed from PS II are provided by PS I. T or F?

A

False, other way around. PS II supplies electrons to PS I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

Water splitting complex is associated with PS I or II?

A

PS II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

PS II is located on the inner side of the membrane of the ________

A

thylakoid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What is phosphorylation?

A

process by which ATP is synthesized by cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Where does phosphorylation take place?

A

in mitochondria and chloroplasts

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What is photo-phosphorylation?

A

synthesis of ATP from ADP and inorganic phosphate in presence of light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

When PS II and PS I work in a series, ________ occurs. When only PS I is functional, ____________ occurs.

A

Non-cyclic photo-phosphorylation,

Cyclic photo-phosphorylation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

Possible location for cyclic photophosphorylation is _______

A

stroma lamellae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Grana membrane or lamellae lacks PS II as well as NADP reductase enzyme. T or F?

A

False, stroma lamellae,

grana lamellae has both PS I and PS II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

In cyclic photophosphorylation, excited electron does not pass on to _________ but is cycled back to the PSI complex through the ___________

A

NADP+,

electron transport chain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Cyclic flow results in the synthesis of _____

A

only ATP, not NADPH + H+

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Cyclic photophosphorylation occurs when only light of ________ is available for excitation

A

wavelength beyond 680nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

What is the chemiosmotic hypothesis?

A

Explanation for ATP synthesis

72
Q

Unlike respiration, in photosynthesis, ATP synthesis is linked to development of a proton gradient across a membrane. T or F?

A

False, LIKE respiration, everything else is correct

73
Q

ATP synthesis in occurs across ___ membrane in the case of photosynthesis.

A

thylakoid

74
Q

In respiration, protons accumulate in __________ whereas in photosynthesis they accumulate ___________

A

intermembrane space of the mitochondria,

inside of the membrane

75
Q

What are the three processes that result in creation of a photon gradient?

A
  1. Photolysis of water
  2. Pumping of H+
  3. Formation of NADPH
76
Q

Splitting of water molecule takes place on _____ (outer / inner) side of the thylakoid membrane. Protons accumulate within the ________ (lumen / stroma)

A

inner, lumen

77
Q

During chemiosmosis, which has a higher concentration of H+ ions? Stroma or lumen?

A

Lumen

78
Q

As electrons move through the photosystems, ________ are transported across the membrane

A

photons

79
Q

Why are photons transported across the membrane due to PS electron movement?

A

primary electron accepter (located towards the outside of the membrane) transfers electron not to an electron carrier but an H carrier (proton from stroma)

When this molecule passes on its electron to the second electron carrier on inner side => proton released in the lumen

80
Q

NADP reductase enzyme (FNR) is located on ______ (lumen / stroma) side of the membrane.

A

Stroma

81
Q

Along with electrons that come from ___________, protons are necessary for the reduction of NADP+ to _______

A

acceptor of electrons of PS I,

NADPH + H+

82
Q

Protons for the reduction of NADP+ are removed from _________

A

stroma

83
Q

Accumulation of protons creates a gradient across the membrane as well as measurable ________ in pH in the lumen

A

decrease

84
Q

Breakdown of the proton gradient leads to the synthesis of _______

A

ATP

85
Q

Protons move across the membrane from lumen to stroma through ____________

A

CF0 of the ATP synthase

86
Q

ATP synthase enzyme consists of ___ parts? What are they?

A

2 parts
CF0 - transmembrane channel embedded in thylakoid membrane
CF1 - protrudes on outer surface of thylakoid membrane on stroma side

87
Q

CF0 carries out ____ diffusion of protons across membrane

A

facilitated

88
Q

Breakdown of the gradient creates enough energy to cause a ________ change in the _____ particle of the ATP synthase which makes it synthesize ATP

A

conformational, CF1

89
Q

Chemiosmosis requires? (4)

A

membrane
proton pump
proton gradient
ATP synthase

90
Q

Energy is not required to pump protons to create a gradient. T or F?

A

False, it is required

91
Q

Once protons have accumulated in the lumen, _______ has a channel that allows _______ of protons back across the membrane

A

ATP synthase, diffusion

92
Q

What part of the chemiosmosis process releases enough energy to catalyse the formation of ATP?

A

diffusion of protons BACK across the membrane (from lumen to stroma)

93
Q

NADPH and ATP are both used eventually in the biosynthetic reaction fixing CO2 and synthesis of sugars. T or F?

A

False, used immediately - not eventually

94
Q

Products of light reaction are?

A

ATP, NADPH, O2

95
Q

After light reactions, where does O2 produced go?

A

diffuses out of the chloroplast

96
Q

What is biosynthetic phase?

A

synthesis of food/sugars using ATP and NADPH, not directly dependent on light (dark reaction)

97
Q

_______ used ____________ in algal photosynthesis to discover the first CO2 fixation product was ____________

A

Melvin Calvin, radioactive 14C,

3-carbon organic acid / 3-phosphoglyceric acid (PGA)

98
Q

The complete _________ is called Calvin cycle.

A

biosynthetic pathway

99
Q

________ pathway has PGA as the first product of CO2 fixation.
__________ pathway has OAA as the first product of CO2 fixation.

A

C3 pathway.

C4 pathway

100
Q

In C4 pathway plants, there are ____ carbon atoms in the first product. The acid is called __________

A

4, oxaloacetic acid (OAA)

101
Q

Acceptor molecule of CO2 has _____ carbons, though scientists thought it would have ______

A

5, 2

102
Q

The acceptor molecule of CO2 is __-carbon ____ sugar aka _______

A

5-carbon ketose sugar,

ribulose biphosphate RuBP

103
Q

Calvin cycle works in a _____ manner i.e. RuBP is regenerated.

A

cyclic

104
Q

Calvin pathways occurs in almost all photosynthetic plants. T or F?

A

False, occurs in ALL

105
Q

Calvin cycle has how many stages? What are they?

A

Carboxylation
Reduction
Regeneration

106
Q

Carboxylation?

A

fixation of CO2 into a stable organic intermediate

107
Q

___________ is the most crucial step of the Calvin cycle

A

Carboxylation of RuBP

108
Q

Carboxylation of RuBP is catalysed by the enzyme __________ which results in the formation of ________

A

RuBP carboxylase,

two molecules of 3-PGA

109
Q

The more correct name for enzymeRuBP is __________ given it also has an oxygenation activity

A

Ribulose Biphosphate Carboxylase-Oxygenase (RuBisCO)

110
Q

_________ is the second stage of the Calvin cycle where _______ is formed.

A

Reduction,

glucose/carbohydrate/sucrose/starch

111
Q

Reduction in Calvin Cycle is a series of reactions in which carbohydrate is formed at expense of photochemically made ATP and NADPH. T or F?

A

True

112
Q

Steps involved in reduction utilize ____ molecules of ATP for phosphorylation and ____ of NADPH for reduction per CO2 molecule fixed.

A

2, 2

113
Q

The fixation of ___ molecules of CO2 and ____ turns of the Calvin cycle are required for one molecule of glucose

A

6, 6

114
Q

What happens in regeneration phase of Calvin cycle?

A

RuBP is regenerated using 1 molecule of ATP

115
Q

_____ ATP molecules are required for phosphorylation to form RuBP in regeneration.

A

1

116
Q

To produce 1 molecule of glucose, how many CO2, ATP and NADPH molecules are required?

A

6, 18, 12

117
Q

What are the 3 products of Calvin Cycle?

A

Glucose, ADP, NADP

118
Q

Cyclic phosphorylation helps in making up for what difference?

A

Cyclic Phosphorylation creates ATP not NADPH => to make up for the different number of ATP and NADPH used in dark reaction (18 ATP vs 12 NADPH)

119
Q

Plants adopted to tropical regions have the _____ pathways.

A

C4

120
Q

C4 pathway plants use C3 pathway / Calvin cycle as the main biosynthetic pathway. T or F?

A

True

121
Q

How are C4 plants special? (5)

A 
special type of leaf anatomy
can tolerate higher temperatures
respond to high light intensities
lack photorespiration
greater biomass productivity
122
Q

The large cells around the vascular bundles in C4 plants are called ________. These leaves are said to have ______ anatomy.

A

bundle sheath cells, Kranz anatomy

123
Q

‘Kranz’ anatomy is named after the biologist who discovered the C4 pathway and special leaf anatomy of C4 plants. T or F?

A

False, Kranz = wreath => arrangement of bundle sheath cells around vascular bundles

124
Q

Features of Kranz anatomy?

A 
- wreath structure
bundle sheath cells have:
- large number of chloroplasts
- thick walls impervious to gaseous exchange
- no intercellular spaces
125
Q

What is the Hatch and Slack pathway?

A

C4 pathway

126
Q

Calvin cycle is cyclic process but Hatch and Slack is a linear pathway. T or F?

A

False, both cyclical

127
Q

Primary CO2 acceptor in H&S pathway is ___________ and is present in ______ cells

A

3-carbon molecule phosphoenol pyruvate (PEP);

mesophyll cells

128
Q

Enzyme responsible for CO2 fixation in H&S pathway?

A

PEP carboxylase / PEPcase

129
Q

Mesophyll cells in both C4 and C3 plants have RuBisCO enzymes as both are capable of Calvin cycle. T or F?

A

False. C4 plants do not.

130
Q

Bundle sheath cells of C4 plants have RuBisCO enzymes, just like C3 plants. T or F?

A

True

131
Q

Bundle sheath cells of C4 plants have PEPcase to catalyze the 3-carbon molecule phosphoenol pyruvate (PEP). T or F?

A

False, that’s mesophyll cells. Bundle sheath cells have RuBisCo for C3, not PEP case.

132
Q

OAA is formed in _____ cells of C4 plants.

A

Mesophyll

133
Q

C4 acid forms other 4-carbon compounds like ______ or _______ in the H&S pathway.

A

malic acid, aspartic acid.

134
Q

C4 acid forms 4-carbon compounds transported from _______ to _______ cells.

A

mesophyll to bundle sheath

135
Q

In ________ cells, C4 acids are broken down to release ________ and ________. This process is called?

A

bundle sheath cells, CO2, 3-carbon molecule;

Decarboxylation

136
Q

3-carbon molecule is transported from bundle sheath back to mesophyll cell to _______

A

be converted to PEP again, completing the cycle (regeneration)

137
Q

In C4 plants, CO2 in bundle sheath cells enters the ______ pathway

A

Calvin / C3

138
Q

Calvin pathway occurs in mesophyll cells of C3 and even C4 plants. T or F?

A

False,
C3 - mesophyll
C4 - bundle sheath

139
Q

What is an important process that occurs in C3 plants only?

A

Photorespiration

140
Q

What is the reaction for the first CO2 fixation step in Calvin cycle?

A

RuBP + CO2 —-RuBisCo—-> 2 x 3PGA

141
Q

_________ is the most abundant enzyme in the world

A

RuBisCo

142
Q

Active site of RuBisCo can bind to both CO2 and O2. T or F?

A

True

143
Q

RuBisCO has much greater affinity for _____ when ratio of ____ is nearly equal

A

CO2, CO2:O2

144
Q

RuBisCO binding is competitive. What does this mean?

A

Relative concentration of O2 and CO2 that determines which will bind to enzyme.

145
Q

What happens in photorespiration? i.e. when O2 binds to RuBisCO

A

RuBP binds with O2 to form 1 molecule of phosphoglycerate and phosphoglycolate (2 Carbon)
No synthesis of sugars, ATP or NADPH.
Releases CO2 and utilizes ATP.

146
Q

Biological function of photorespiration is to produce sucrose and starch in plants. T or F?

A

False, function unknown

147
Q

Why do C4 plants not photorespire?

A

Mechanism that increases concentration of CO2 i.e. CO2 released in bundle sheath cells when C4 acid is broken down => intracellular concentration of CO2 is increased

148
Q

In C4 plants, increased concentration of CO2 ensures that RuBisCo functions as a ____________ minimizing the _______ activity

A

carboxylase, oxygenase

149
Q

Initial carboxylation reaction occurs in mesophyll for both C3 and C4 plants. T or F?

A

True

150
Q

Rate of photosynthesis is important in determining ________

A

crop yield

151
Q

Internal factors affecting photosynthesis? (6)

A 
Number,
size,
age and orientation of leaves,
mesophyll cells and chloroplasts,
internal CO2 concentration
amount of chlorophyll
152
Q

External factors affecting photosynthesis? (4)

A

Availability of sunlight,
temperature,
CO2 concentration,
water

153
Q

At any point, photosynthesis rate will be determined by ___ factor

A

sub-optimal / limiting factor

154
Q

_________ stated the Law of Limiting Factors in _____ year

A

Blackman, 1905

155
Q

Law of Limiting Factors are applicable to any biochemical process, not just photosynthesis. T or F?

A

True

156
Q

What are the 3 aspects of light factor that can affect photosynthesis?

A

Quality, intensity and duration of exposure

157
Q

At higher light intensities, the rate of photosynthesis will always increase, demonstrating their linear relationship. T or F?

A

False, true in lower light intensities. In higher, other limiting factors.

158
Q

Light saturation occurs at ____ percent of the full sunlight.

A

10 per cent

159
Q

Why is light rarely a limiting factor in nature?

A

Just 10% of sunlight can be saturation for plants, they don’t need too much.

160
Q

Increase in light beyond a point causes the breakdown of chlorophyll and decrease in photosynthesis. T or F?

A

True

161
Q

___________ is a major limiting factor for photosynthesis. Why?

A

CO2.

Concentration is very low in atmosphere

162
Q

CO2 concentration in atmosphere is between ___ and ___ percent

A

0.03 to 0.04%

163
Q

Increase in concentration up to ____% can cause increase in CO2 fixation rates, beyond that level it comes damaging over longer periods

A

0.05%

164
Q

C3 and C4 plants respond similarly to CO2 concentrations. T or F?

A

False

165
Q

Describe how C3 and C4 plants respond to high CO2 conditions in low light and high light conditions.

A

Low light - neither group responds
High light - both show increase in rate of photosynthesis, however, C4 plants show saturation at 360 μl/L whereas C3 at 450 μl/L

166
Q

Current availability of CO2 levels is limiting only to C3 plants. T or F?

A

True

167
Q

An example of how humans use the knowledge that C3 plants respond to higher CO2 concentration?

A

Greenhouse crops (tomatoes, bell pepper) grown in CO2 enriched atmosphere => higher yield

168
Q

Dark reactions are temperature controlled. Why?

A

Enzymatic

169
Q

Dark reactions are temperature sensitive but less so than light reactions. T or F?

A

False, reverse

170
Q

C4 plants respond to higher rate of photosynthesis in _______ temperatures (higher / lower)

A

Higher

171
Q

Temperature optimum for photosynthesis of different plants also depends on _______

A

habitat

172
Q

Water has a direct effect on photosynthesis. T or F?

A

False, indirect

173
Q

Examples of effect of water on photosynthesis

A

water stress => stomata close => less CO2 available

water stress => leaves wilt => reduce surface area of leaves => reduce metabolism

174
Q

Within chloroplasts, membranes are the sites for light reaction while the chemosynthetic pathway occurs in stroma. T or F?

A

True

175
Q

RuBisCO also catalyses a wasteful carboxylation reaction in C3 plants: photorespiration. T or F?

A

False, wasteful oxygenation reaction.

Biology (NCERT) - Class XI (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions