Q1. Identify the correct statements for 'Z-scheme': (i) Movement of electrons is downhill on redox potential scale. (ii) PS I electrons are excited by 700 nm wavelength. (iii) Electrons are used up as they pass through ETS.
Correct Answer: (a)
Electrons are not used up; they are passed to pigments or NADP+.
Q2. In the 'Half-leaf' experiment using KOH, the leaf portion inside the tube tested negative for starch because:
Correct Answer: (b)
KOH soaked cotton absorbs CO2, showing that CO2 is essential for photosynthesis.
Q3. Who worked out the complete biosynthetic pathway of photosynthesis using radioactive 14C?
Correct Answer: (a)
Melvin Calvin mapped the pathway of carbon assimilation.
Q4. T.W Engelmann used which organism to detect the sites of O2 evolution?
Correct Answer: (b)
He used aerobic bacteria which accumulated in blue and red light regions where O2 was being evolved.
Q5. Assertion: Cyclic photophosphorylation results only in ATP synthesis.
Reason: Stroma lamellae lack PS II and NADP reductase.
Correct Answer: (a)
Lack of NADP reductase prevents NADPH formation, forcing cyclic flow to produce only ATP.
Q6. Water stress causes photosynthesis rates to decline mainly because it:
Correct Answer: (b)
Water stress causes stomata to close, reducing CO2 availability and making leaves wilt.
Q7. Which is the most abundant plant pigment in the world?
Correct Answer: (c)
Chlorophyll a is the chief and most abundant pigment associated with photosynthesis.
Q8. Match the scientist in Column I with their contribution in Column II:
Column I
Column II
A. Joseph Priestley
(I) Action spectrum of photosynthesis
B. Jan Ingenhousz
(II) Discovered oxygen
C. Julius von Sachs
(III) Role of sunlight in purifying air
D. T.W Engelmann
(IV) Glucose stored as starch
Correct Answer: (a)
Priestley discovered O2; Ingenhousz showed role of light; Sachs evidence for starch; Engelmann action spectrum.
Q9. Which are correct for 'Chloroplast pigments'? (i) Chl a is bright green. (ii) Carotenoids are yellow to yellow-orange. (iii) Pigments absorb light at specific wavelengths.
Correct Answer: (a)
Summary of pigment properties.
Q10. In C4 plants, the large cells around the vascular bundles are called:
Correct Answer: (b)
C4 plants have large cells around vascular bundles called bundle sheath cells.
Q11. Regarding 'Splitting of water': (i) Occurs in PS II. (ii) Releases O2 and protons. (iii) Protons are released into the lumen.
Correct Answer: (a)
Standard water photolysis details.
Q12. A milestone contribution showing that O2 evolved comes from H2O and not CO2 was made by:
Correct Answer: (a)
Van Niel inferred this from studies of purple and green sulphur bacteria.
Q13. Assertion: Light is rarely a limiting factor in nature.
Reason: Light saturation occurs at 10% of full sunlight.
Correct Answer: (a)
Because plants saturate early, light intensity is usually sufficient.
Q14. The 3-carbon molecule formed after decarboxylation in C4 plants is transported back to:
Correct Answer: (c)
It returns to the mesophyll to be converted back to PEP.
Q15. Assertion: Photosynthesis is the primary source of all food on earth.
Reason: It releases oxygen into the atmosphere.
Correct Answer: (b)
Both are true, but oxygen release is not the reason why it is the source of food (the reason is carbon fixation).
Q16. During cyclic photophosphorylation, which of the following is produced?
Correct Answer: (a)
Cyclic flow results only in the synthesis of ATP, but not of NADPH + H+ or O2.
Q17. Photosynthesis is a _____ process.
Correct Answer: (c)
The intro defines it as a physico-chemical process.
Q18. Match the reaction with its site in the chloroplast:
Column I
Column II
A. Light reaction
(I) Stroma
B. Dark reaction
(II) Membranous system (Grana)
C. Splitting of water
(III) Inner side of thylakoid membrane
D. ATP synthesis
(IV) Across thylakoid membrane
Correct Answer: (a)
Light reaction in grana; Dark in stroma; Water splitting inner side; ATP synthesis across membrane.
Q19. Julius von Sachs provided evidence in 1854 that glucose is usually stored as:
Correct Answer: (c)
Sachs showed glucose is produced and stored as starch.
Q20. Light harvesting complexes (LHC) are also known as:
Correct Answer: (b)
LHCs are made of hundreds of pigment molecules forming a light harvesting system called antennae.
Q21. The CO2 concentration in the atmosphere is between:
Correct Answer: (b)
The atmospheric concentration of CO2 is very low (0.03-0.04 percent).
Q22. Which plant shows a higher temperature optimum?
Correct Answer: (c)
C4 plants are adapted to dry tropical regions and tolerate higher temperatures.
Q23. Regarding 'Photosynthetic Rate': (i) At low light, it is linearly related to intensity. (ii) CO2 concentration of 0.05% is ideal for C3 productivity. (iii) Water stress directly increases rate.
Correct Answer: (a)
Water stress decreases the rate.
Q24. The splitting of water is associated with:
Correct Answer: (b)
Splitting of water is associated with PS II on the inner side of the thylakoid membrane.
Q25. The pigment responsible for the 'yellow' color in leaves is:
Correct Answer: (c)
Xanthophylls appear yellow in a chromatogram.
Q26. Photorespiration is a 'wasteful' process because:
Correct Answer: (b)
Photorespiration does not produce ATP or NADPH and results in the release of CO2.
Q27. The empirical equation for photosynthesis in oxygen-evolving organisms is:
Correct Answer: (a)
The text provides this as the understood empirical equation by the mid-19th century.
Q28. Which scientist showed that only the green part of the plants could release oxygen?
Correct Answer: (a)
Ingenhousz showed using aquatic plants that bubbles (oxygen) formed only around green parts in sunlight.
Q29. Which statements regarding Photorespiration are correct? (i) In C3 plants, O2 binds with RuBisCO. (ii) It results in the synthesis of sugars. (iii) ATP is utilized in this pathway.
Correct Answer: (a)
No synthesis of sugars occurs in photorespiration.
Q30. In C4 plants, the Calvin cycle takes place in:
Correct Answer: (b)
In C4 plants, the Calvin pathway occurs only in the bundle sheath cells.
Q31. Assertion: C4 plants are more productive than C3 plants.
Reason: C4 plants lack the process of photorespiration.
Correct Answer: (a)
Absence of photorespiration allows for higher efficiency and productivity.
Q32. Regarding the Calvin Cycle, identify the correct statements: (i) RuBP is a 5-carbon ketose sugar. (ii) Six molecules of CO2 are required for one glucose. (iii) Reduction requires 18 ATP for one glucose.
Correct Answer: (a)
Reduction needs 12 ATP for glucose; the cycle total is 18 ATP.
Q33. Identify the correct features of 'Hatch and Slack Pathway': (i) Primary fixation occurs in mesophyll. (ii) OAA is converted to malic acid. (iii) RuBisCO is absent in bundle sheath.
Correct Answer: (a)
RuBisCO is rich in bundle sheath cells.
Q34. Assertion: RuBisCO is the most abundant enzyme in the world.
Reason: Its active site can bind to both CO2 and O2.
Correct Answer: (b)
Both are true, but being a bifunctional enzyme is not the reason for its abundance in nature.
Q35. Match the metabolic pathway with its environment:
Column I
Column II
A. C3 plants
(I) Dry tropical regions
B. C4 plants
(II) Temperate regions
Correct Answer: (a)
C4 plants are tropical adaptations.
Q36. Match the enzyme with its function:
Column I
Column II
A. RuBisCO
(I) Fixes CO2 in mesophyll of C4
B. PEPcase
(II) ATP synthesis
C. ATP synthase
(III) Fixes CO2 in C3 pathway
D. Carbonic anhydrase
(IV) Speeds up H2CO3 formation
Correct Answer: (a)
Correct enzyme-function associations as per text.
Q37. The pigment chlorophyll a is called the chief pigment because:
Correct Answer: (b)
The action spectrum of photosynthesis shows maximum rates in blue and red regions where chlorophyll a absorbs most.
Q38. The primary CO2 acceptor in the Calvin cycle is:
Correct Answer: (c)
The acceptor molecule is a 5-carbon ketose sugar, ribulose bisphosphate (RuBP).
Q39. Which of the following is the basis of all life on earth?
Correct Answer: (a)
Photosynthesis is the basis of life because it is the primary source of food and releases oxygen.
Q40. Kranz anatomy is a characteristic feature of:
Correct Answer: (b)
The 'wreath' arrangement of cells in C4 leaves is called Kranz anatomy.
Q41. Match the following for C4 leaf anatomy:
Column I
Column II
A. Bundle sheath cells
(I) Large number of chloroplasts
B. Mesophyll cells
(II) PEP carboxylase present
C. Kranz
(III) Wreath
Correct Answer: (a)
Attributes of C4 Kranz anatomy.
Q42. The first CO2 fixation product in C4 plants is:
Correct Answer: (c)
In C4 plants, the first product is the 4-carbon acid, OAA.
Q43. Match the factor with its effect:
Column I
Column II
A. High light intensity
(I) Chlorophyll breakdown
B. Water stress
(II) Stomatal closure
C. Low temperature
(III) Inactive enzymes
Correct Answer: (a)
Environmental effects on photosynthesis.
Q44. During the biosynthetic phase, ATP and NADPH are used to convert:
Correct Answer: (b)
They drive the processes leading to the synthesis of food/sugars.
Q45. Match the steps of the Calvin Cycle with requirements per CO2:
Q46. Where is the proton accumulation (gradient) created during ATP synthesis in chloroplasts?
Correct Answer: (c)
In photosynthesis, proton accumulation is towards the inside of the membrane, i.e., in the lumen.
Q47. The 'Law of Limiting Factors' was proposed by:
Correct Answer: (a)
Blackman (1905) proposed the Law of Limiting Factors.
Q48. The enzyme RuBisCO has an affinity for:
Correct Answer: (c)
RuBisCO's active site can bind to both CO2 and O2, making it a carboxylase-oxygenase.
Q49. To make one molecule of glucose, how many turns of the Calvin cycle are required?
Correct Answer: (c)
Six turns of the cycle are required for one glucose molecule.
Q50. Which scientist used radioactive isotopes to prove that oxygen comes from water?
Correct Answer: (c)
The text states this was proven using radioisotopic techniques following van Niel’s inference.
Q51. The first stable product of CO2 fixation in C3 plants is:
Correct Answer: (b)
The first CO2 fixation product in C3 plants is a 3-carbon acid, PGA.
Q52. Match the following for Calvin cycle turns:
Product
Turns required
A. 1 Glucose
(I) 6
B. 1 CO2 fixed
(II) 1
Correct Answer: (a)
Standard cycle counts.
Q53. Which pigment appears as 'bright or blue-green' in a chromatogram?
Correct Answer: (a)
Section 11.4 lists Chlorophyll a as bright or blue-green.
Q54. Match the products formed in different organisms (van Niel):
Column I (Organism)
Column II (Product)
A. Green plants
(I) Sulphur/Sulphate
B. Purple sulphur bacteria
(II) Oxygen
Correct Answer: (a)
Based on the hydrogen donor used (H2O vs H2S).
Q55. Which statements about C4 plants are true? (i) They tolerate higher temperatures. (ii) They show a response to high light intensities. (iii) They have photorespiration.
Q56. Which of the following are the products of light reaction used in biosynthetic phase?
Correct Answer: (a)
ATP and NADPH produced in light reactions are used to drive sugar synthesis.
Q57. The primary acceptor of CO2 in C3 plants is a:
Correct Answer: (c)
RuBP is a 5-carbon ketose sugar.
Q58. Match the following for CO2 concentration:
Condition
CO2 level
A. Atmospheric
(I) 0.05 %
B. Fixation increases up to
(II) 0.03 - 0.04 %
Correct Answer: (a)
Levels specified in section 11.10.2.
Q59. The first step of the Calvin cycle is:
Correct Answer: (c)
Carboxylation is the fixation of CO2 into a stable organic intermediate.
Q60. The C4 acid (Malic/Aspartic) is broken down in bundle sheath cells to release:
Correct Answer: (b)
Decarboxylation in bundle sheath cells releases CO2 and a C3 molecule.
Q61. Assertion: Water stress reduces photosynthesis.
Reason: It causes wilting of leaves and reduces metabolic activity.
Correct Answer: (a)
Mechanical and physiological effects of water loss hinder the process.
Q62. Match the following for C3 and C4 plants:
Column I
Column II
A. Primary CO2 acceptor (C3)
(I) PEP
B. Primary CO2 acceptor (C4)
(II) RuBP
C. First stable product (C3)
(III) OAA
D. First stable product (C4)
(IV) PGA
Correct Answer: (a)
C3: RuBP/PGA; C4: PEP/OAA.
Q63. Accessory pigments like chlorophyll b and carotenoids help by:
Correct Answer: (c)
They enable a wider range of light to be used and protect chlorophyll a.
Q64. Cyclic photophosphorylation occurs when only light of wavelengths beyond _____ is available.
Correct Answer: (b)
It occurs when light of wavelengths beyond 680 nm are available for excitation of PS I.
Q65. Stroma lamellae lack which of the following?
Correct Answer: (c)
Stroma lamellae membranes lack PS II as well as NADP reductase enzyme.
Q66. Total ATP required to make one molecule of glucose in C3 plants is:
Correct Answer: (b)
6 turns x 3 ATP per turn = 18 ATP.
Q67. Assertion: The first CO2 fixation product in C3 plants is PGA.
Reason: PGA is a 3-carbon organic acid.
Correct Answer: (b)
Both are true, but being 3-carbon doesn't explain why it is the first product.
Q68. Green plants are called autotrophs because they:
Correct Answer: (b)
The text defines autotrophs as green plants that synthesise the food they need.
Q69. The major limiting factor for photosynthesis in nature is:
Correct Answer: (c)
CO2 is the major limiting factor as its concentration in the atmosphere is very low.
Q70. Regarding Chemiosmotic hypothesis, which are correct? (i) ATP synthesis is linked to proton gradient. (ii) ATP synthase is located on the stroma lamellae only. (iii) Protons move from lumen to stroma through CF0.
Correct Answer: (a)
ATP synthase is not restricted only to stroma lamellae.
Q71. Correct statements about 'RuBisCO': (i) Most abundant enzyme. (ii) Acts as carboxylase in C4 plants. (iii) Acts as oxygenase in C3 plants under low CO2.
Correct Answer: (a)
RuBisCO's roles across different plant types.
Q72. Which of the following statements about light reactions are correct? (i) They occur in the membranous system of chloroplast. (ii) They include water splitting and O2 release. (iii) They result in the formation of ATP and NADPH.
Correct Answer: (a)
Section 11.5 summary of light reaction.
Q73. Correct statements about 'Action Spectrum': (i) It shows the rate of photosynthesis at different wavelengths. (ii) Maximum rate is in blue and red light. (iii) It has no relation to the absorption spectrum.
Correct Answer: (a)
Action spectrum closely resembles the absorption spectrum of chlorophyll a.
Q74. Select correct statements about 'limiting factors': (i) Blackman proposed it in 1905. (ii) Rate is limited by the factor nearest to its minimal value. (iii) Temperature affects the light reaction more than dark reaction.
Correct Answer: (a)
Temperature affects the dark (enzymatic) reaction more.
Q75. Which enzyme is absent in the mesophyll cells of C4 plants?
Correct Answer: (b)
The mesophyll cells of C4 plants lack RuBisCO enzyme.
Q76. Match the part of ATP synthase:
Column I
Column II
A. CF0
(I) Facing stroma
B. CF1
(II) Embedded in membrane
Correct Answer: (a)
Structural components of ATPase.
Q77. Match the absorption peak:
Column I (System)
Column II (Peak)
A. PS I
(I) P680
B. PS II
(II) P700
Correct Answer: (a)
PS I is P700; PS II is P680.
Q78. Assertion: In C4 plants, the bundle sheath cells have no intercellular spaces.
Reason: These cells have thick walls impervious to gaseous exchange.
Correct Answer: (a)
The structural features prevent CO2 leakage and maintain high concentration.
Q79. Match the photophosphorylation type:
Column I
Column II
A. Non-cyclic
(I) PS I only
B. Cyclic
(II) PS I and PS II
Correct Answer: (a)
Non-cyclic uses both systems; cyclic uses only PS I.
Q80. In C3 plants, photorespiration occurs because RuBisCO binds with:
Correct Answer: (c)
Binding of RuBisCO with O2 leads to photorespiration.
Q81. What happens when light intensity is increased beyond the point of saturation?
Correct Answer: (b)
Light beyond a point causes chlorophyll breakdown and a decrease in photosynthesis.
Q82. Assertion: Splitting of water takes place on the inner side of the thylakoid membrane.
Reason: Protons produced by splitting of water accumulate in the stroma.
Correct Answer: (b)
Protons accumulate in the lumen, not the stroma.
Q83. Which type of plants lack photorespiration?
Correct Answer: (b)
C4 plants have a CO2-concentrating mechanism that prevents RuBisCO from acting as an oxygenase.
Q84. The wavelength of light at which maximum absorption by chlorophyll a occurs is in:
Correct Answer: (b)
Chlorophyll a shows peaks in the blue and red regions.
Q85. Who discovered oxygen in 1774?
Correct Answer: (b)
Joseph Priestley discovered oxygen in 1774 through his bell jar experiments.
Q86. In Photosystem I (PS I), the reaction centre chlorophyll a has an absorption peak at:
Correct Answer: (b)
PS I reaction centre is called P700.
Q87. The movement of electrons in the Z-scheme from PS II to the acceptor is:
Correct Answer: (b)
The jump of electrons into orbit and to an acceptor is described as uphill.
Q88. Assertion: Dark reactions are not light-dependent.
Reason: They occur only in darkness.
Correct Answer: (c)
Both are false; they depend on light products and do not strictly occur only in darkness.
Q89. Greenhouse crops like tomatoes are grown in CO2 enriched atmospheres to:
Correct Answer: (b)
Higher CO2 leads to increased rates of photosynthesis and higher productivity.
Q90. The primary CO2 acceptor in C4 plants is:
Correct Answer: (c)
PEP is the primary acceptor in the mesophyll cells of C4 plants.
Q91. Match the pigment with its color in chromatogram:
Q92. How many ATP molecules are required for every CO2 molecule entering the Calvin cycle?
Correct Answer: (b)
For every CO2 fixed, 3 ATP and 2 NADPH are required.
Q93. Light saturation for most plants occurs at ____ of full sunlight.
Correct Answer: (b)
Light saturation occurs at 10 per cent of full sunlight.
Q94. Which plants show saturation at lower CO2 levels (around 360 µlL-1)?
Correct Answer: (b)
C4 plants show saturation at about 360 µlL-1 while C3 respond up to 450 µlL-1.
Q95. Which of the following is correct? (i) PS I absorption peak is 700 nm. (ii) Non-cyclic flow produces ATP and NADPH. (iii) Photosynthesis occurs only in green leaves.
Correct Answer: (a)
It occurs in other green parts too (e.g., stems).
Q96. The CF1 part of ATP synthase:
Correct Answer: (c)
CF1 protrudes on the outer surface of the thylakoid membrane facing the stroma.
Q97. The enzyme responsible for ATP synthesis in the thylakoid is:
Correct Answer: (c)
ATP synthase (composed of CF0 and CF1) catalyses ATP formation.
Q98. In Photosystem II (PS II), the reaction centre chlorophyll a has an absorption peak at:
Correct Answer: (a)
PS II reaction centre is called P680.
Q99. Within the chloroplast, where do the 'dark reactions' (carbon reactions) take place?
Correct Answer: (c)
Enzymatic reactions to synthesise sugar take place in the stroma.
Q100. Identify the correct phylum/group being described: (i) They tolerate high light intensities. (ii) They have Kranz anatomy. (iii) Examples include Maize and Sorghum.
Correct Answer: (b)
Description of C4 plants.
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