60+ MCQ on Photosynthesis for NEET
Studying Photosynthesis is not an easy task because it is quite a vast topic, making it hard to prepare for exams. Not only for Cell Biology but several other entrance exams as well. There are many websites and online tools that can help a lot in the study routine. If you are preparing for NEET it is essential to be an expert in the Photosynthesis concept. We brought a complete guide for you to prepare for Photosynthesis MCQ free of cost.
Not everyone can pay and take a course, that’s why we’ve collected all Topics wise and other important MCQ on Photosynthesis that provide the most diverse materials to study for the exams that will put you in Pharmacy and Medical College. There are good practices for studying Photosynthesis MCQ Questions and Answers in general.
Important Points to Remember About Photosynthesis
- Photosynthesis is the process used by plants, algae, and certain bacteria to harness energy from sunlight and turn it into chemical energy. Here, we describe the general principles of photosynthesis and highlight how scientists are studying this natural process to help develop clean fuels and sources of renewable energy.
- There are two types of photosynthetic processes: oxygenic photosynthesis and anoxygenic photosynthesis.
- Oxygenic photosynthesis functions as a counterbalance to respiration by taking in the carbon dioxide produced by all breathing organisms and reintroducing oxygen to the atmosphere.
- On the other hand, anoxygenic photosynthesis uses electron donors other than water. The process typically occurs in bacteria such as purple bacteria and green sulfur bacteria, which are primarily found in various aquatic habitats.
- Oxygenic photosynthesis is written as follows: 6CO2 + 12H2O + Light Energy → C6H12O6 + 6O2 + 6H2O
- Similarly, the various anoxygenic photosynthesis reactions can be represented as a single generalized formula: CO2 + 2H2A + Light Energy → [CH2O] + 2A + H2O
- Photosynthesis takes place in the chloroplast. The chlorophyll present in the chloroplast traps the light from the sun and carries out the process.
MCQ on Photosynthesis for NEET
1. Photosynthesis occurs in___
(a) Chloroplast
(b) Golgi body
(c) Endoplasmic reticulum
(d) Nucleus
Answer: (a) Chloroplast
Explanation: Photosynthesis takes place in chloroplasts, which contain chlorophyll that captures light energy for the synthesis of food.
Read: Plant Physiology MCQ with Answers Pdf
2. Rate of photosynthesis does not depend upon:
(a) Quality of light
(b) Intensity of Light
(c) Duration of Light
(d) Temperature
Answer: (c) Duration of Light
Explanation: While quality, intensity, and temperature directly affect photosynthesis, duration only matters when considering daily cycles, not the rate.
Read: Plant Cell Multiple Choice Questions
3. For photosynthesis green plants require:
(a) Chlorophyll only
(b) Light
(c) Carbon dioxide and water
(d) All of the above
Answer: (d) All of the above
Explanation: Chlorophyll, light, carbon dioxide, and water are all essential components for photosynthesis in green plants.
Read: MCQ on Plant Harmone Pdf
4. The optimum temperature for photosynthesis is
(a) 25–35℃
(b) 10–15℃
(c) 35–40℃
(d) 20–25℃
Answer: (d) 20–25℃
Explanation: Most plants show maximum photosynthetic efficiency between 20–25℃ under normal atmospheric conditions.
Read: MCQ on Nutrition in Plants with Answers Pdf
5. Photosynthesis is a _____ process.
(a) Catabolic
(b) Anabolic
(c) Exothermic
(d) Metabolic
Answer: (b) Anabolic
Explanation: Photosynthesis is anabolic because it synthesizes glucose from carbon dioxide and water using light energy.
Read: MCQ on Plant Tissue Culture
6. Photorespiration occurs in____
(a) Four cell organelles
(b) Two cell organelles
(c) One cell organelle
(d) Three cell organelle
Answer: (d) Three cell organelle
Explanation: Photorespiration occurs across chloroplasts, peroxisomes, and mitochondria.
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7. Name the pigment which is responsible for the absorption of light in plants?
(a) Chlorophyll
(b) Stoma
(c) Xylem
(d) Phloem
Answer: (a) Chlorophyll
Explanation: Chlorophyll is the green pigment that captures light energy needed for photosynthesis.
Read: MCQ on Transportation in Plants and Animals
8. Reduction of NADP occurs in
(a) Oxidative photophosphorylation
(b) Cyclic photophosphorylation
(c) Non-cyclic photophosphorylation
(d) None
Answer: (c) Non-cyclic photophosphorylation
Explanation: In the non-cyclic process, electrons reduce NADP to NADPH.
Read: Anatomy of flowering Plants NEET MCQ
9. In bacteria name the color of light which is responsible for photosynthesis?
(a) Ultra-Violet
(b) Blue
(c) Red
(d) None of the above
Answer: (c) Red
Explanation: Red light is most effective for bacterial photosynthesis as it penetrates deepest and has optimal energy for excitation.
Read: MCQ on Plant Growth and Development
10. Kranz anatomy is found in the leaves of
(a) Wheat
(b) Mustard
(c) Potato
(d) Sugarcane
Answer: (d) Sugarcane
Explanation: Sugarcane is a C4 plant that exhibits Kranz anatomy—distinct bundle sheath cells surrounding vascular bundles.
Read: Morphology of flowering Plants NEET Questions
11. Quantasomes are found in:
(a) Cristae of mitochondria
(b) Thylakoid membrane of chloroplasts
(c) Nucleus membrane
(d) Lysosome
Answer: (b) Thylakoid membrane of chloroplasts
Explanation: Quantasomes are photoactive units found embedded in the thylakoid membranes; they contain chlorophyll and other pigments.
Read: MCQ on Transgenic Plants
12. Peroxisomes are involved in which type of reactions
(a) Calvin cycle
(b) Glyoxylate cycle
(c) Glycolytic cycle
(d) Bacterial photosynthesis
Answer: (c) Glycolytic cycle
Explanation: Peroxisomes are involved in reactions of the glycolate pathway (photorespiration), which includes glycolytic processes.
Read: Respiration in Plants NEET MCQ
13. Name the metal present in chlorophyll ‘a’ and ‘b’?
(a) Iron
(b) Copper
(c) Magnesium
(d) Manganese
Answer: (c) Magnesium
Explanation: Magnesium is the central metal ion in the chlorophyll molecule, essential for light absorption.
Read: Plant kingdom mcq for NEET
14. Photorespiration involves oxidation of
(a) PGA
(b) RuBP
(c) Chlorophyll a
(d) Both a and b
Answer: (b) RuBP
Explanation: In photorespiration, RuBP reacts with oxygen instead of carbon dioxide, leading to its oxidation.
15. Name the structural unit of photosynthesis?
(a) Thylakoid
(b) Grana
(c) Stroma
(d) Chlorophyll
Answer: (a) Thylakoid
Explanation: Thylakoids are membrane-bound structures where the light-dependent reactions of photosynthesis occur.
16. C3 and C4 plants differ with respect to___
(a) Number of ATP molecules consumed
(b) First product
(c) Substrate which accepts carbon dioxide
(d) All
Answer: (d) All
Explanation: C3 and C4 plants differ in their carbon fixation pathway, ATP requirement, and first CO₂ fixation product.
17. Which of the following statements are true regarding Photosystems?
(a) Photosystems are arrangements of chlorophyll and other pigments packed into thylakoids.
(b) Many Prokaryotes have only one photosystem.
(c) Both A and B are correct.
(d) Only A is correct.
Answer: (c) Both A and B are correct.
Explanation: Photosystems are pigment complexes in thylakoids; prokaryotes typically possess only one photosystem.
18. In Calvin cycle, 1 molecule of glucose is formed from
(a) 6CO₂ + 30ATP + 12NADPH
(b) 6CO₂ + 12ATP
(c) 6CO₂ + 18ATP + 12NADPH
(d) 6CO₂ + 18ATP + 30NADPH
Answer: (c) 6CO₂ + 18ATP + 12NADPH
Explanation: The Calvin cycle uses 6 CO₂ molecules, 18 ATP, and 12 NADPH to synthesize 1 glucose molecule.
19. Name the physiochemical process in which chemical energy is produced by light energy with the help of a photosynthetic organism?
(a) Photosynthesis
(b) Respiration
(c) Oxidative decarboxylation
(d) Oxidative phosphorylation
Answer: (a) Photosynthesis
Explanation: Photosynthesis converts light energy into chemical energy stored in glucose, using carbon dioxide and water.
20. Where does a light reaction take place?
(a) Grana
(b) Stroma
(c) Cytoplasm
(d) Endoplasmic reticulum
Answer: (a) Grana
Explanation: Light-dependent reactions take place in the grana, specifically in the thylakoid membranes of chloroplasts.
21. Classification of organisms as oxygenic or anoxygenic during photosynthesis is based on ______
(a) The presence of CO₂
(b) The generation of oxygen
(c) The presence of light
(d) The presence of water
Answer: (b) The generation of oxygen
Explanation: Organisms are classified as oxygenic if oxygen is released during photosynthesis (e.g., plants, algae), and anoxygenic if not (e.g., some bacteria).
22. Electrons from the excited chlorophyll molecules of PS-II are first accepted by___
(a) Pheophytin
(b) Ferredoxin
(c) Cytochrome f
(d) Cytochrome b
Answer: (a) Pheophytin
Explanation: In PS-II, the first electron acceptor from excited chlorophyll is pheophytin, an electron carrier molecule.
23. Which of the following is not a lipid-soluble photosynthetic pigment?
(a) Phycobilins
(b) Carotenoids
(c) Chlorophyll
(d) Xanthophylls
Answer: (a) Phycobilins
Explanation: Phycobilins are water-soluble pigments found in cyanobacteria and red algae; others are lipid-soluble.
24. Non-cyclic photophosphorylation results in the production of___
(a) NADH
(b) NADPH
(c) ATP
(d) ATP and NADPH
Answer: (d) ATP and NADPH
Explanation: Non-cyclic photophosphorylation produces both ATP and NADPH using electrons from water.
25. Which of these features are not of chlorophyll?
(a) It has Mg²⁺ as the central metal ion
(b) It has a cyclopentanone ring fused with a pyrrole ring
(c) It has a planar tetrapyrrole ring structure
(d) It is a water-soluble pigment
Answer: (d) It is a water-soluble pigment
Explanation: Chlorophyll is lipid-soluble, embedded in thylakoid membranes, not water-soluble.
26. DCMU inhibits
(a) PS-I
(b) PS-II
(c) Oxidative phosphorylation
(d) It destroys chloroplast
Answer: (b) PS-II
Explanation: DCMU (diuron) is a herbicide that blocks electron flow in PS-II, halting photosynthesis.
27. Name the pigment which is responsible for the yellow color of leaves in autumn and the orange color of carrots?
(a) Phycobilins
(b) Chlorophylls
(c) Carotenoids
(d) Bacteriochlorophyll
Answer: (c) Carotenoids
Explanation: Carotenoids are responsible for yellow, orange, and red hues in plants and are visible when chlorophyll degrades.
28. Maximum photosynthesis occurs in
(a) Blue light
(b) Red light
(c) White light
(d) Green light
Answer: (b) Red light
Explanation: Red light (around 680 nm) is most effective for photosynthesis, followed by blue light.
29. The first acceptor of CO₂ in C4 plants is
(a) Aspartic acid
(b) Malic acid
(c) Oxaloacetic acid
(d) Phosphoenolpyruvate
Answer: (d) Phosphoenolpyruvate
Explanation: In C4 plants, CO₂ is initially fixed by PEP to form oxaloacetic acid.
30. Name the mechanism which prevents photo-oxidative damage in plants?
(a) Photosynthesis
(b) Photorespiration
(c) Photoprotection
(d) Photoprotection
Answer: (c) Photoprotection
Explanation: Photoprotection includes mechanisms like non-photochemical quenching to dissipate excess light energy safely.
31. The first product of the C4 pathway is
(a) PGA
(b) DHAP
(c) Oxaloacetate
(d) Phosphoenolpyruvate
Answer: (c) Oxaloacetate
Explanation: In the C4 pathway, CO₂ combines with phosphoenolpyruvate (PEP) to form oxaloacetate, a four-carbon compound.
32. Name the photosynthetic pigment which is structurally similar to bile pigment bilirubin?
(a) Chlorophyll
(b) Carotene
(c) Xanthophyll
(d) Phycobilins
Answer: (d) Phycobilins
Explanation: Phycobilins are open-chain tetrapyrroles, structurally similar to bile pigments like bilirubin.
33. The two pigment system theory of photosynthesis was proposed by
(a) Aron
(b) Blackman
(c) Hill
(d) Emerson
Answer: (d) Emerson
Explanation: Emerson proposed the two pigment system theory (PS-I and PS-II) based on the red drop and enhancement effects.
34. What is the location of photosynthetic pigment in an oxygenic photosynthetic organism?
(a) Plasma membranes
(b) Thylakoid membranes
(c) Chromatophores
(d) Chlorosome
Answer: (b) Thylakoid membranes
Explanation: In oxygenic photosynthetic organisms like plants, pigments are embedded in the thylakoid membranes of chloroplasts.
35. H₂ donor during photosynthesis is
(a) ATP
(b) NADP
(c) NADPH
(d) NADH
Answer: (c) NADPH
Explanation: NADPH serves as the reducing agent (hydrogen donor) in the Calvin cycle during CO₂ fixation.
36. What is the absorption spectrum?
(a) The graph produced by absorption of light
(b) The graph shows the photochemical reaction
(c) The graph produced by absorption of oxygen
(d) The graph shows oxygen evolution at a different wavelength
Answer: (a) The graph produced by absorption of light
Explanation: Absorption spectrum shows how much light is absorbed by pigments at different wavelengths.
37. The minerals involved in splitting reaction during photosynthesis is
(a) Potassium and manganese
(b) Magnesium and chlorine
(c) Potassium and chlorine
(d) Manganese and chlorine
Answer: (d) Manganese and chlorine
Explanation: Manganese and chlorine are essential cofactors in the oxygen-evolving complex of PS-II during water splitting.
38. Name the filamentous fungi which are used in Engelmann’s experiment to show photosynthetic activity?
(a) Rhizopus stolonifer
(b) Penicillium
(c) Cyanobacteria
(d) Spirogyra
Answer: (d) Spirogyra
Explanation: Engelmann used Spirogyra and aerobic bacteria to demonstrate the action spectrum of photosynthesis.
39. Water-soluble photosynthetic pigment is
(a) Chlorophyll a
(b) Xanthophyll
(c) Anthocyanin
(d) Chlorophyll b
Answer: (c) Anthocyanin
Explanation: Anthocyanins are water-soluble pigments responsible for red, purple, or blue colors in plants.
40. Which of the following term defines the production of heat and light when an excited molecule returns to its original state?
(a) Fluorescence
(b) Luminescence
(c) Intersystem crossing
(d) Phosphorescence
Answer: (a) Fluorescence
Explanation: Fluorescence occurs when a molecule releases energy as light immediately upon returning to the ground state.
41. In photosynthesis dark reaction, is called so because–
(a) It occurs in dark.
(b) It does not require light energy.
(c) It cannot occur during the daytime.
(d) It occurs more rapidly at night.
Answer: (b) It does not require light energy.
Explanation: The dark reaction (Calvin cycle) does not directly depend on light but uses ATP and NADPH from the light reaction.
42. What is resonance energy transfer?
(a) Transfer of electrons between the molecules
(b) The transfer of energy as well as electrons
(c) The transfer of electrons but not the energy
(d) The transfer of energy but not the electron
Answer: (d) The transfer of energy but not the electron
Explanation: Resonance energy transfer allows excitation energy to pass between pigment molecules without moving electrons.
43. How many photons are absorbed to produce one molecule of oxygen?
(a) Two
(b) Ten
(c) Twelve
(d) Eight
Answer: (d) Eight
Explanation: Eight photons are needed (four for each PS-II activation cycle) to split two water molecules and release one O₂.
44. Which of the following is a Hill reagent?
(a) Sugar
(b) Chlorophylls
(c) 2,6-dichlorophenolindophenol
(d) Nicotinamide adenine dinucleotide phosphate
Answer: (c) 2,6-dichlorophenolindophenol
Explanation: Hill reagents are artificial electron acceptors used to demonstrate the light-dependent release of oxygen.
45. What is the red drop phenomenon?
(a) Falling of red color in the spectrum
(b) Drop-in quantum yield in the red region of the spectrum
(c) Drop-in quantum yield in the far-red region of the spectrum
(d) Falling of far-red color in the spectrum
Answer: (c) Drop-in quantum yield in the far-red region of the spectrum
Explanation: The red drop refers to a decline in photosynthetic efficiency beyond 680 nm, as PS-I alone can’t drive the full process.
46. Which of the following correctly defines the yield of oxygen by the no. of photons absorbed?
(a) Emerson enhancement effect
(b) Quantum requirement
(c) Photochemical reaction
(d) Quantum Yield
Answer: (d) Quantum Yield
Explanation: Quantum yield is the number of oxygen molecules released per number of photons absorbed.
47. Name the scientist, who first pointed out that plants purify foul air by bell jar experiment?
(1) Willstatter
(2) Robert Hooke
(3) Priestley
(4) Jean Senebier
Answer: (3) Priestley
Explanation: Joseph Priestley’s bell jar experiment in 1771 demonstrated that plants restore air made impure by burning or breathing.
48. Of the total amount of water absorbed by the plant, its actual percentage used during photosynthesis is:
(1) 50%
(2) 90%
(3) 1%
(4) 25%
Answer: (3) 1%
Explanation: Only about 1% of absorbed water is used in photosynthesis; the rest is lost via transpiration or used in other processes.
49. Moll’s half leaf experiment explains that_______
(1) Carbon dioxide is essential for photosynthesis
(2) Chlorophyll and water are necessary for photosynthesis
(3) Light and water are essential for photosynthesis
(4) All the above are correct
Answer: (1) Carbon dioxide is essential for photosynthesis
Explanation: In Moll’s experiment, half of a leaf is exposed to CO₂ and the other half is not, demonstrating its necessity.
50. Oxygen during photosynthesis comes from the water was proved with the help of O₁₈ experiment by________
(1) Ruben and Kamen
(2) Hill
(3) Warburg
(4) Blackman
Answer: (1) Ruben and Kamen
Explanation: Ruben and Kamen used radioactive isotope O₁₈ to trace oxygen origin, confirming it comes from water, not CO₂.
51. Name the scientist who pointed out the importance of different wavelengths of light using green algae and aerobic bacteria.
(1) Priestley
(2) Ingen-Housz
(3) K.V. Thimann
(4) Englemann
Answer: (4) Englemann
Explanation: Engelmann used a prism to split light and observed bacterial movement around Spirogyra filaments in red and blue light, showing which wavelengths are most effective in photosynthesis.
52. Photosynthesis in C₄ plants is relatively less limited by atmospheric CO₂ levels because:
(1) Four carbon acids are the primary initial CO₂ fixation products
(2) The primary fixation of CO₂ is mediated via PEP carboxylase
(3) Effective pumping of CO₂ into bundle sheath cells
(4) Rubisco in C₄ plants has a higher affinity for CO₂
Answer: (3) Effective pumping of CO₂ into bundle sheath cells
Explanation: C₄ plants concentrate CO₂ in bundle sheath cells, ensuring Rubisco operates in a high CO₂ environment, reducing photorespiration.
53. Due to increase in concentration of CO₂_______
(1) Photosynthesis increases
(2) Photosynthesis decreases
(3) Water absorption efficiency increases
(4) Water absorption efficiency decreases
Answer: (1) Photosynthesis increases
Explanation: CO₂ is a raw material for photosynthesis; increased availability enhances the rate until a saturation point is reached.
54. Choose the correct statement about C₄ plants:
(1) Mesophyll cells possess RuBisCO
(2) Neither mesophyll cells nor bundle sheath cells pose RuBisCO
(3) Mesophyll cells have PEPcase which convert CO₂ into OAA
(4) Bundle sheath cells synthesize OAA which is a 4 carbon compound
Answer: (3) Mesophyll cells have PEPcase which convert CO₂ into OAA
Explanation: In C₄ plants, PEPcase in mesophyll cells fixes CO₂ into oxaloacetic acid (OAA), which is then transported to bundle sheath cells.
55. In CAM plants, photophosphorylation occurs in:
(1) Bundle sheath cell, during night
(2) Mesophyll cell, during daytime
(3) Mesophyll cell, during night
(4) Bundle sheath cell, during daytime
Answer: (2) Mesophyll cell, during daytime
Explanation: CAM plants open stomata at night to fix CO₂ but carry out light reactions (photophosphorylation) during the day in mesophyll cells.
56. In the Calvin cycle, CO₂ is fused with primary acceptor molecules to form 3C compound phosphoglycerate. If in this reaction CO₂ provides one carbon, then how many carbons are present in the primary acceptor molecule?
(1) Five carbons
(2) Two carbons
(3) Six carbons
(4) Three carbons
Answer: (1) Five carbons
Explanation: CO₂ (1C) combines with RuBP (5C) to form an unstable 6C compound, which splits into two molecules of PGA (3C each).
57. In photosynthesis, NADPH + H⁺ are oxidised in:
(1) Calvin cycle
(2) Non-cyclic photophosphorylation
(3) Cyclic photophosphorylation
(4) Z-scheme
Answer: (1) Calvin cycle
Explanation: NADPH + H⁺ are used as reducing agents in the Calvin cycle to reduce 3-PGA to glyceraldehyde-3-phosphate.
58. Enzyme which can catalyze both carboxylation and oxygenation of RuBP in the chloroplast is not found in which of the following cells?
(1) Mesophyll cells of C₄ plants
(2) Mesophyll cells of C₃ plants
(3) Mesophyll cells of CAM plants
(4) Bundle sheath cells of C₄ plants
Answer: (1) Mesophyll cells of C₄ plants
Explanation: In C₄ plants, Rubisco is confined to bundle sheath cells, while mesophyll cells contain PEP carboxylase, not Rubisco.
59. Why are C₄ plants more efficient?
(1) They show photorespiration
(2) They have RuBisCO in mesophyll cells
(3) They can tolerate high temperature
(4) They have a mechanism of concentrating CO₂ at the place of RuBisCO enzyme action.
Answer: (4) They have a mechanism of concentrating CO₂ at the place of RuBisCO enzyme action.
Explanation: C₄ plants deliver CO₂ directly to Rubisco in bundle sheath cells, minimizing photorespiration and increasing efficiency.
60. Which part of the chloroplast is directly involved in the light reaction of photosynthesis?
(a) Grana
(b) Stroma
(c) Outer membrane
(d) Inner membrane
Answer: (a) Grana
Explanation: Grana contain thylakoid membranes with embedded photosystems, where light reactions of photosynthesis take place.