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mcqs of
,
1 : Green light gives:
A
:
Least photosynthesis
B
:
Maximum Photosynthesis
C
:
High absorption
D
:
No oxygen
2 : If NADPH is absent:
A
:
CO₂ is fixed
B
:
Glucose not formed
C
:
Light absorbed
D
:
O₂ released
3 : Heavy oxygen experiment proved:
A
:
CO₂ gives O₂
B
:
Water gives O₂
C
:
NADPH stores O₂
D
:
ATP releases O₂
4 : Why do plants appear green in color?
A
:
Green light is absorbed
B
:
Blue light is reflected
C
:
Green light is reflected
D
:
All colors are absorbed
5 : Which part of the Chlorophyll molecule is hydrophobic?
A
:
Pyrrole ring
B
:
Porphyrin
C
:
Hydrocarbon tail
D
:
Magnesium center
6 : What holds the pyrrole rings of chlorophyll together?
A
:
Iron atom
B
:
Nitrogen atoms
C
:
Magnesium atom
D
:
Carbon atoms
7 : What is primary function of accessory pigments?
A
:
Absorb red light
B
:
Release oxygen
C
:
Store glucose
D
:
Transfer energy to chlorophyll a
8 : Which pigment is present in the reaction center of both photosystems?
A
:
Chlorophyll b
B
:
Carotene
C
:
Chlorophyll a
D
:
Xanthophylls
9 : What provides energy in photosynthesis?
A
:
Light
B
:
Water
C
:
CO₂
D
:
Glucose
10 : Which structure contains photosynthesis pigments in plant cells?
A
:
Nucleus
B
:
Thylakoid
C
:
Cytoplasm
D
:
Mitochondria
11 : Which structure connects grana in chloroplasts?
A
:
Lamella
B
:
Stroma
C
:
Outer membrane
D
:
Thylakoid lumen
12 : CO₂ reduced by:
A
:
Oxygen
B
:
NADPH
C
:
Chlorophyll
D
:
Water
13 : NADPH acts as:
A
:
Enzyme
B
:
Pigment
C
:
Reducing agent
D
:
Light absorber
14 : Closed stomata reduce:
A
:
Light
B
:
Water loss
C
:
CO₂ entry
D
:
Pigment
15 : Role of water in photosynthesis:
A
:
Splits to release oxygen
B
:
Makes starch
C
:
Stores light
D
:
Fixes carbon
16 : Why is the electron transport chain important in photosynthesis?
A
:
It absorbs light
B
:
It generates NADPH and ATP
C
:
It fixes CO₂
D
:
It reflects green light
17 : Maximum photosynthesis occurs in:
A
:
Yellow light
B
:
Green light
C
:
Red and blue light
D
:
White light
18 : Rubisco fixes:
A
:
Hydrogen
B
:
Water
C
:
Carbon dioxide
D
:
Oxygen
19 : Which part of photosynthesis occurs on Thylakoid membrane?
A
:
Carbon fixation
B
:
Glucose production
C
:
Light dependent reactions
D
:
Calvin cycle
20 : Action spectrum shows:
A
:
CO₂ use
B
:
Light absorption
C
:
Water Transport
D
:
Heat loss
21 : CO₂ enters through:
A
:
Roots
B
:
Stem
C
:
Stomata
D
:
Veins
22 : Engelmann used:
A
:
Moss
B
:
Pine
C
:
Spirogyra
D
:
Algae
23 : Which photosystem absorbs light of 680 nm most efficiently?
A
:
PS-II
B
:
PS-I
C
:
ATP Synthase
D
:
Electron carrier
24 : Which pigment primarily participates in the reaction center of photosynthesis?
A
:
Carotene
B
:
Xanthophyll
C
:
Chlorophyll a
D
:
Chlorophyll b
25 : Which statement best differentiates cyclic from non-cyclic photophosphorylation?
A
:
Only PS-I works in cyclic
B
:
Oxygen is formed in cyclic
C
:
NADPH is not formed in cyclic
D
:
Forms Chlorophyll
26 : What would happen if the Calvin cycle were interrupted?
A
:
ATP production would increase
B
:
Glucose production would stop
C
:
Photosynthesis would be enhanced
D
:
Oxygen production would increase
27 : How does ATP formation occur during electron transport?
A
:
Through the light directly
B
:
Via chemiosmosis
C
:
Through water uptake
D
:
By glucose breakdown
28 : How is energy from light stored during photosynthesis?
A
:
As glucose
B
:
In CO₂
C
:
In water molecule
D
:
In ATP and NADPH
29 : What is ATP synthase's role in Photosynthesis?
A
:
Splits water
B
:
Synthesizes ATP
C
:
Absorbs water
D
:
Transfers electrons
30 : Why is photolysis of water essential in photosynthesis?
A
:
Forms NADP+
B
:
Releases carbon dioxide
C
:
Fills electron gap in P680
D
:
Forms Chlorophyll
31 : Why is the Calvin cycle important for life on Earth?
A
:
It produces ATP for plants
B
:
It converts CO₂ into glucose for energy
C
:
It produces oxygen for respiration
D
:
It absorbs light for photosynthesis
32 : How is Calvin cycle affected in absence of light?
A
:
The cycle stops immediately
B
:
The cycle continues using stored ATP and NADPH
C
:
The cycle produces glucose at a faster rate
D
:
The cycle uses light from other sources
33 : How does the Calvin Cycle contribute to glucose synthesis?
A
:
By formation of ATP
B
:
By converting G3P into glucose
C
:
By reducing CO₂ to glucose
D
:
By producing NADPH for glucose synthesis
34 : Difference between the reduction and regeneration phases of the Calvin cycle:
A
:
Reduction forms glucose, and regeneration uses RuBP
B
:
Reduction uses ATP, and regeneration uses NADPH
C
:
Reduction forms G3P, and regeneration forms RuBP
D
:
Reduction fixes CO₂, and regeneration forms glucose
35 : What happens if NADPH accumulates in chloroplast?
A
:
Calvin cycle speeds up
B
:
Cyclic photophosphorylation begins
C
:
Photolysis increases
D
:
Glucose is oxidized
36 : Why is the Calvin cycle also called the dark reaction?
A
:
It occurs at night
B
:
It does not require light directly
C
:
It occurs in dark reactions
D
:
It produces glucose in darkness
37 : What is the primary product of carbon fixation in the Calvin cycle?
A
:
Glucose
B
:
3-Phosphoglycerate
C
:
RuBP
D
:
G3P
38 : What role does Rubisco play in the Calvin cycle?
A
:
It reduces G3P to glucose
B
:
It fixes carbon dioxide to RuBP
C
:
It produces NADPH
D
:
It synthesizes ATP
39 : What is the Calvin Cycle?
A
:
A set of light-dependent reactions in the stroma
B
:
A set of light-independent reactions in the stroma
C
:
A pathway that produces glucose
D
:
A process that requires sunlight for glucose production
40 : The pigment for absorbing light is:
A
:
Rubisco
B
:
NADPH
C
:
Chlorophyll
D
:
ATP
41 : Why is alcoholic fermentation beneficial for yeast?
A
:
Survive without oxygen
B
:
Produce more energy
C
:
Generate lactic acid
D
:
Use CO₂ to make glucose
42 : What happens if glucose is not metabolized in respiration?
A
:
Use lipids for fuel
B
:
Same ATP production
C
:
More oxygen available
D
:
Increase glucose production
43 : Why do muscle cells use lactic acid fermentation during exercise?
A
:
To increase oxygen intake
B
:
To produce ATP
C
:
To release glucose
D
:
To generate heat
44 : How does glycolysis function in both types of respiration?
A
:
Splits glucose
B
:
Generates ATP
C
:
Produces oxygen
D
:
Requires oxygen
45 : Difference between alcoholic and lactic acid fermentation:
A
:
Ethanol vs. Lactic acid
B
:
Muscle vs. yeast
C
:
Requires oxygen vs. Not require
D
:
Both in human
46 : Why is anaerobic respiration less efficient?
A
:
Faster glucose use
B
:
Less ATP produced
C
:
More oxygen needed
D
:
More waste produced
47 : What is produced in alcoholic fermentation?
A
:
Lactic acid
B
:
Ethanol + CO₂
C
:
Oxygen, Glucose
D
:
Water, Energy
48 : How much ATP is produced in anaerobic respiration?
A
:
2 ATP
B
:
4 ATP
C
:
38 ATP
D
:
1 ATP
49 : Which of the following is a product of glycolysis?
A
:
Pyruvic acid
B
:
Lactic acid
C
:
Oxygen
D
:
Water
50 : What is the function of NAD+ in glycolysis?
A
:
Donates a phosphate group
B
:
Breaks down glucose
C
:
Accepts hydrogen ions
D
:
Produces ATP
51 : What is the main purpose of cellular respiration?
A
:
Break down glucose
B
:
Produce glucose
C
:
Store energy
D
:
Release CO₂ and Water
52 : Main product of photosynthesis is:
A
:
Oxygen
B
:
Glucose
C
:
Water
D
:
ATP
53 : Where does glycolysis occur?
A
:
Mitochondria
B
:
Cytosol
C
:
Nucleus
D
:
Chloroplast
54 : What is the importance of NADH in aerobic respiration?
A
:
Supplies electrons to the electron chain
B
:
Directly produces ATP
C
:
Breaks down glucose
D
:
Converts pyruvic acid into lactic acid
55 : Why is glycolysis important in both aerobic and anaerobic respiration?
A
:
Produces ATP without oxygen
B
:
Generates oxygen
C
:
Breaks down glucose into oxygen
D
:
Produces large amount of carbon dioxide
56 : How does pyruvic acid change before entering the Krebs cycle?
A
:
Converted to glucose
B
:
Forms acetyl-CoA after losing CO₂
C
:
Convert to lactic acid
D
:
Remains unchanged
57 : Why is oxygen necessary for the stages after glycolysis in aerobic respiration?
A
:
ATP production
B
:
Convert pyruvic acid to lactic acid
C
:
Final electron acceptor
D
:
Provides energy for glycolysis
58 : How does the Krebs cycle contribute to energy production?
A
:
It produces glucose from pyruvate
B
:
It stores oxygen for cellular use
C
:
It produces ATP and electron carriers like NADH and FADH₂
D
:
It directly produces oxygen for the cell
59 : Why is the Krebs cycle also called the citric acid cycle?
A
:
Because citric acid is the final product
B
:
Because citric acid is the most abundant molecule
C
:
Because citric acid is the first product formed
D
:
Because citric acid is oxidized in the cycle
60 : What is the initial molecule that combines with acetyl-CoA in the Krebs cycle?
A
:
Fumaric acid
B
:
Oxaloacetic acid
C
:
Malic acid
D
:
Succinic acid
61 : Where does the Krebs cycle occur in the cell?
A
:
Cytoplasm
B
:
Nucleus
C
:
Mitochondria
D
:
Golgi apparatus
62 : How does the energy released from glucose during aerobic respiration benefit cells?
A
:
Stored as glucose
B
:
Forms ATP, powers functions
C
:
Released as heat
D
:
Stored as fat
63 : What is the first molecule formed in the Krebs cycle?
A
:
Citric acid
B
:
Alpha-ketoglutaric acid
C
:
Succinic acid
D
:
Malic acid
64 : What is the importance of NADH in aerobic respiration?
A
:
Supplies electrons to the electron transport chain
B
:
Breaks down glucose
C
:
Converts pyruvic acid to lactic acid
D
:
Directly produces ATP
65 : How does the energy release from glucose during aerobic respiration benefit cells?
A
:
Stored as glycogen
B
:
Forms ATP, powers functions
C
:
Released as heat
D
:
Stored as fat
66 : What would happen if the electron transport chain were blocked?
A
:
ATP production would increase
B
:
Oxygen consumption would increase
C
:
The cell would rely on anaerobic respiration
D
:
The Krebs cycle would stop
67 : Where does the electron transport chain occur in the cell?
A
:
Cytoplasm
B
:
Mitochondrial inner membrane
C
:
Nucleus
D
:
Plasma membrane
68 : What is produced when NADH is oxidized in the electron transport chain?
A
:
Two ATP
B
:
One ATP
C
:
Three ATP
D
:
Four ATP
69 : What is the final electron acceptor in the electron transport chain?
A
:
Oxygen
B
:
Carbon dioxide
C
:
Water
D
:
NAD+
70 : How does chemiosmosis contribute to ATP production?
A
:
By adding phosphate groups to glucose
B
:
By using energy from electrons to pump protons across the membrane
C
:
By reducing NADH to NAD+
D
:
By splitting glucose into pyruvic acid
71 : Why is oxygen important for cellular respiration?
A
:
It forms ATP
B
:
It combines with electrons to form water
C
:
It acts as a proton pump
D
:
It increases the energy yield of glycolysis
72 : How do lipids contribute to ATP production in cellular respiration?
A
:
Lipids are converted to glucose for glycolysis
B
:
Fatty acids are converted to acetyl CoA, which enters the Krebs cycle
C
:
Lipids are used to produce NADH and FADH₂ directly
D
:
Lipids are converted to lactic acid for ATP production
73 : Why do C-4 plants have specialized cells?
A
:
To isolate CO₂ and O₂, reducing photorespiration
B
:
To reduce water loss
C
:
To increase oxygen production
D
:
To enhance nitrogen uptake
74 : How does C-4 photosynthesis help in hot climates?
A
:
Concentrates CO₂, reduces photorespiration
B
:
Slows Calvin cycle
C
:
Increases oxygen supply
D
:
Improves water use efficiency
75 : Why is photorespiration problematic for crops in hot climates?
A
:
Increases rate, reduces yield
B
:
Reduces oxygen production
C
:
Inefficient light absorption
D
:
Low photosynthesis efficiency
76 : How does temperature affect photorespiration rate?
A
:
Increases oxygen fixation by Rubisco
B
:
No effect
C
:
Lowers competition for Rubisco
D
:
Decreases photorespiration
77 : Why does photorespiration decrease photosynthesis efficiency?
A
:
Loss of fixed carbon
B
:
Produces more ATP
C
:
Accelerates Calvin cycle
D
:
Prevents oxygen buildup
78 : Which molecule is formed from phosphoglycolate?
A
:
Glyoxylate
B
:
Glycine
C
:
Serine
D
:
Malate
79 : What does Rubisco do in photorespiration?
A
:
Breaks down RuBP to phosphoglycolate
B
:
Synthesizes glucose
C
:
Fixes CO₂ in Calvin cycle
D
:
Converts glycerate to phosphoglycerate
80 : Which plants use CAM metabolism?
A
:
Cacti, pineapples
B
:
All tropical trees
C
:
Only C-3 plants
D
:
All aquatic plants
81 : What is photorespiration?
A
:
Oxygen used, CO₂ released in light
B
:
ATP produced in green cells
C
:
Occurs in mitochondria
D
:
Only in dark
82 : How does CAM contribute to plant survival in arid regions?
A
:
Fixes CO₂ during the day
B
:
Minimizes water loss
C
:
Increases transpiration
D
:
Fixes CO₂ in soil
83 : How does CAM help Cacti survive?
A
:
Stomata open during the day
B
:
Prevents glucose formation
C
:
Stores CO₂ at night
D
:
Reduces oxygen intake at night
84 : What is the function of CAM metabolism in hot climates?
A
:
Fix CO₂ in the morning
B
:
Fix CO₂ at night
C
:
Increase photorespiration
D
:
Open stomata all day
85 : How does CAM reduce photorespiration?
A
:
By absorbing CO₂ during the day
B
:
By storing CO₂ at night
C
:
By storing oxygen for later use
D
:
By reducing water intake
86 : Why is CAM metabolism beneficial for desert plants?
A
:
CO₂ is fixed only at night
B
:
Stomata open during the day
C
:
Increases photosynthesis during the day
D
:
Limits oxygen intake
87 : Why do CAM plants close their stomata during the day?
A
:
To prevent oxygen intake
B
:
To conserve water
C
:
To absorb CO₂ at midday
D
:
To absorb more oxygen
88 : Which is an advantage of CAM in agriculture?
A
:
Increases water usage
B
:
Makes plants drought-resistant
C
:
Increases plant growth rate
D
:
Limits CO₂ absorption
89 : Where do light dependent reactions take place?
A
:
Stroma
B
:
Cytoplasm
C
:
Thylakoid membrane
D
:
Outer membrane
90 : What is the main purpose of light dependent reactions?
A
:
Produce glucose
B
:
Absorb carbon dioxide
C
:
Form ATP and NADPH
D
:
Split sugars
91 : What is CAM metabolism?
A
:
Stomata open during the day
B
:
Stomata open at night
C
:
Only occurs in aquatic plants
D
:
Only occurs in C-3 plants
92 : Which wavelengths are least absorbed by Chlorophylls?
A
:
Blue
B
:
Green
C
:
Red
D
:
Violet
93 : What is the energy transfer path in plants?
A
:
Carotenoids → Chlorophyll a
B
:
Chlorophyll a → Xanthophylls
C
:
Chlorophyll b → CO₂
D
:
Chlorophyll a → Carotenes
Chapter 6 : Bioenergetics
Biology 11th MCQs || Ilam Ghar
Biology 11th
