These Photosynthesis In Higher Plants NEET Questions and Answers and Answers are composed by our livemcqs team speacially for NEET, AIIMS and other Medical Entrance aspirents. These Photosynthesis NEET Questions covers the all concepts of the Chapter 13 of Class 11 Biology. You can download these Questions by clicking the Link “Photosynthesis In Higher Plants NEET Questions PDF” given below.
Contents
Photosynthesis In Higher Plants NEET Questions
1. Which of these is not an internal factor affecting photosynthesis?
| a) Size |
| b) Age |
| c) Number |
| d) Water |
Answer: d
Explanation: Various internal and external factors affect the rate of photosynthesis, which in turn affects the overall productivity and yield of the plant. Size, age and number are internal factors while water is an external factor.
2. What do the internal factors affecting photosynthesis dependent on?
| a) External factors |
| b) Geographical area |
| c) Genetic predisposition |
| d) Species and sub-species |
Answer: c
Explanation: The genetic predisposition or the genetic make up of a plant is an internal factor that affects the rate of photosynthesis. The arrangement of genes present in the plant is expressed in a certain way in different plants.
3. Which of these is not an external factor affecting photosynthesis?
| a) Sunlight |
| b) Temperature |
| c) Leaf orientation |
| d) CO2 concentration |
Answer: c
Explanation: Various internal and external factors affect the rate of photosynthesis, which in turn affects the overall productivity and yield of the plant. Sunlight, temperature and CO2 concentration are external factors.
4. Which of these statements is false regarding the factors affecting photosynthesis?
| a) The leaf orientation of a plant affects photosynthesis |
| b) Both internal and external factors affect photosynthesis |
| c) Photosynthetic rate is determined by a factor at sub-optimal level |
| d) Both CO2 concentration in the environment and inside the plant affect photosynthesis |
Answer: a
Explanation: The rate of photosynthesis is affected by both external and internal factors. The photosynthetic rate is determined by a factor at sub-optimal level which is known as the limiting factor.
5. Which scientist gave the Law of Limiting Factors?
| a) Hooke |
| b) Blackman |
| c) Fleming |
| d) Mendel |
Answer: b
Explanation: Blackman gave the Law of Limiting Factors in 1905. It states that if multiple factors affect a process, then the rate of the process is determined by the factor which is the closest to its minimal value.
6. At what percentage of sunlight does light saturation occur?
| a) 30 |
| b) 20 |
| c) 10 |
| d) 15 |
Answer: c
Explanation: Light is an external factor that affects the rate of photosynthesis. Light saturation occurs at 10% of full sunlight. At high light intensities, the rate of photosynthesis does not increase linearly.
7. What happens when the incident light on a plant is excessive?
| a) RuBP undergoes oxidation |
| b) Vascular bundles lose functionality |
| c) Mesophyll cells are destroyed |
| d) Chlorophyll breaks down |
Answer: d
Explanation: Light is rarely a limiting factor for photosynthesis, but excess amount of light reaching the photosynthetic parts of plant causes the breakdown of chlorophyll and hence, reduces the rate of photosynthesis.
8. What is the atmospheric concentration of carbon dioxide?
| a) 0.3 – 0.4% |
| b) 3 – 4% |
| c) 0.03 – 0.04% |
| d) 0.003 – 0.004% |
Answer: c
Explanation: The atmospheric concentration of carbon dioxide is 0.03 – 0.04%. Carbon dioxide concentration is an important external factor that affects the rate of photosynthesis in all plants.
9. At what concentration do C4 plants show saturation?
| a) 430 μlL-1 |
| b) 450 μlL-1 |
| c) 340 μlL-1 |
| d) 360 μlL-1 |
Answer: d
Explanation: C3 plants and C4 plants show different carbon dioxide concentration saturations. At high intensities of light, C4 plants show carbon dioxide saturation at 360 μlL-1 while C3 plants show saturation at 450 μlL-1.
10. Which of these plants are grown in carbon dioxide enriched atmosphere?
| a) Maize |
| b) Sugarcane |
| c) Tomato |
| d) Millets |
Answer: c
Explanation: Maize, sugarcane and millets are C4 plants. Since C3 plants reach saturation at higher carbon dioxide concentrations, plants such as tomatoes and bell peppers are grown in carbon dioxide enriched atmosphere.
11. Which of these plants have the highest optimum temperature?
| a) Tropical C3 |
| b) Temperate C3 |
| c) Tropical C4 |
| d) Temperate C4 |
Answer: c
Explanation: Tropical plants have a higher optimum temperature than temperate plants. C4 plants show a higher rate of photosynthesis at higher temperatures than C3 plants. Hence, tropical C4 plants have the highest optimum temperature.
12. Why do stomata close during water shortage?
| a) To reduce CO2 availability |
| b) To trap water |
| c) To increase metabolic activity |
| d) To increase the surface area of leaves |
Answer: a
Explanation: During water shortage in plants, the stomata close in order to reduce the availability of carbon dioxide for carbon dioxide fixation, which is the first part of the Calvin cycle of photosynthesis.
13. Which of these is not an effect of water stress?
| a) Closing of stomata |
| b) Increase in metabolism |
| c) Wilting of leaves |
| d) Reduction in surface area of leaves |
Answer: b
Explanation: When there is a water stress, its effects can be seen on the plant. Water stress closes stomata hence carbon dioxide availability reduces. The leaves wilt to reduce surface area and metabolism.
14. Which of these is not a product of light reaction?
| a) Oxygen |
| b) NADPH |
| c) ATP |
| d) NADP |
Answer: d
Explanation: The process of photosynthesis has two stages-the light reaction and the dark reaction. The products of the light reaction are oxygen, ATP and NADPH. The light reaction requires light to carry out its reactions.
15. Which of these diffuse out of the chloroplast after the light reaction?
| a) ATP |
| b) Carbon dioxide |
| c) Oxygen |
| d) NADPH |
Answer: c
Explanation: The process of photosynthesis has two stages-the light reaction and the dark reaction. The products of the light reaction are oxygen, ATP and NADPH. Oxygen diffuses out of the chloroplast.
Photosynthesis NEET Questions
16. Which of these statements is incorrect regarding the biosynthetic phase of photosynthesis?
| a) It depends on carbon dioxide and water |
| b) It depends on the products of light reaction |
| c) ATP and NADH are used |
| d) Sugars are synthesized |
Answer: c
Explanation: The biosynthetic phase of photosynthesis depends upon the products of the light reaction, which are namely oxygen, ATP and NADPH. It leads to the synthesis of food, which are sugars.
17. Which of these scientists have contributed to photosynthesis studies?
| a) Melvin Calvin |
| b) Hargovind Khorana |
| c) Gregor Mendel |
| d) Anthony Van Leeuwenhoek |
Answer: a
Explanation: Melvin Calvin has contributed greatly to photosynthesis studies. The Calvin cycle was named after him. He first identified the compound PGA or 3-phosphoglyceric acid as a product of photosynthesis.
18. Which of these was used by Melvin Calvin for photosynthesis studies?
| a) P-35 |
| b) Radioactive C-14 |
| c) C-13 |
| d) Radioactive S-32 |
Answer: b
Explanation: Melvin Calvin used the radioactive isotope of carbon-12 or C-12, carbon-14 or C-14 in algal photosynthesis studies. This helped in determining the various steps of the Calvin cycle or pathway.
19. Who discovered the first CO2 fixation product?
| a) Anthony Van Leeuwenhoek |
| b) Robert Hooke |
| c) Melvin Calvin |
| d) Gregor Mendel |
Answer: c
Explanation: Melvin Calvin has contributed greatly to photosynthesis studies. The Calvin cycle was named after him. He used radioactive C-14 to discover the first CO2 fixation product of photosynthesis, PGA.
20. Which of these is a 3-carbon organic acid?
| a) PGA |
| b) BTCA |
| c) Citric acid |
| d) Acetic acid |
Answer: a
Explanation: PGA or 3-phosphoglyceric acid is a 3-carbon organic acid. Citric acid has 6 carbon atoms while acetic acid has 2 carbon atoms. PGA is a product of the carbon dioxide fixation stage of photosynthesis.
21. What is the full form of PGA?
| a) 2-phosphoglyceric acid |
| b) 2-phosphoglutamic acid |
| c) 3-phosphoglutamic acid |
| d) 3-phosphoglyceric acid |
Answer: d
Explanation: The full form of PGA is 3-phosphoglyceric acid. 3-phosphoglyceric acid is a product of the carbon dioxide fixation stage of photosynthesis. 3-phosphoglyceric acid is a 3-carbon organic acid.
22. How many carbon atoms does OAA contain?
| a) 3 |
| b) 2 |
| c) 4 |
| d) 1 |
Answer: c
Explanation: OAA or oxaloacetic acid is a 4-carbon compound. It is an organic acid. OAA or oxaloacetic acid is the first stable product of carbon dioxide fixation during photosynthesis, in some plants.
23. Which is the first product of CO2 fixation in the C3 pathway?
| a) NADPH |
| b) OAA |
| c) ATP |
| d) PGA |
Answer: d
Explanation: Carbon dioxide assimilation during photosynthesis is of two types depending upon the first stable product of carbon dioxide fixation. the first product of CO2 fixation in the C3 pathway is PGA.
24. Which is the first product of CO2 fixation in the C4 pathway?
| a) NADPH |
| b) PGA |
| c) OAA |
| d) ATP |
Answer: c
Explanation: Carbon dioxide assimilation during photosynthesis is of two types depending upon the first stable product of carbon dioxide fixation. the first product of CO2 fixation in the C4 pathway is OAA.
25. What is the primary acceptor of CO2 in photosynthesis?
| a) ATP |
| b) PGA |
| c) RuBP |
| d) OAA |
Answer: c
Explanation: The primary acceptor of carbon dioxide in photosynthesis is RuBP or ribulose bisphosphate. Ribulose bisphosphate is a 5-carbon ketose sugar. It accepts carbon dioxide from the atmosphere.
26. Which of these compounds have 5 carbon atoms?
| a) RuBP |
| b) OAA |
| c) PGA |
| d) ATP |
Answer: a
Explanation: RuBP or Ribulose bisphosphate is a 5-carbon ketose sugar. It is the primary acceptor of carbon dioxide in photosynthesis. OAA is a 4-carbon organic acid while PGA is a 3-carbon organic acid.
27. How many carbon atoms does the primary acceptor of CO2 in photosynthesis have?
| a) 4 |
| b) 5 |
| c) 3 |
| d) 2 |
Answer: b
Explanation: RuBP or Ribulose bisphosphate is a 5-carbon ketose sugar. It is the primary acceptor of carbon dioxide in photosynthesis. It accepts carbon dioxide from the atmosphere for the process of photosynthesis.
28. Which of these is not a stage of the Calvin cycle?
| a) Carboxylation |
| b) Reduction |
| c) Regeneration |
| d) Oxidation |
Answer: d
Explanation: The Calvin cycle is a pathway of light independent reactions of photosynthesis. It depends on the energy carriers ATP and NADPH and hence, Calvin cycle indirectly depends upon light.
29. Which is the most crucial step of the Calvin cycle?
| a) Oxidation |
| b) Reduction |
| c) Carboxylation |
| d) Regeneration |
Answer: c
Explanation: The Calvin cycle is a pathway of light independent reactions of photosynthesis. The most crucial step of the Calvin cycle is carboxylation, where carbon dioxide is fixated into a stable organic intermediate.
30. Which of these undergoes carboxylation during Calvin cycle?
| a) NADPH |
| b) ATP |
| c) RuBP |
| d) PGA |
Answer: c
Explanation: The most crucial step of the Calvin cycle is carboxylation, where carbon dioxide is fixated into a stable organic intermediate. This organic intermediate is RuBP or ribulose bisphosphate.
NEET Questions On Photosynthesis In Higher Plants
31. Which of these substances catalyse carboxylation?
| a) RuBP carboxylase |
| b) Pyruvate carboxylase |
| c) Propionyl-CoA carboxylase |
| d) Acetyl-CoA carboxylase |
Answer: a
Explanation: The most crucial step of the Calvin cycle is carboxylation, where carbon dioxide is fixated into a stable organic intermediate, known as ribulose bisphosphate. RuBP carboxylase catalyses carboxylation.
32. What is the product of carboxylation?
| a) 2-PGA |
| b) 3-PGA |
| c) RuBP |
| d) Rubisco |
Answer: b
Explanation: 3-PGA or 3-phosphoglyceric acid is the product of carboxylation. It is a 3-carbon organic acid. RuBP or ribulose bisphosphate is the primary carbon dioxide acceptor which undergoes carboxylation.
33. How many molecules of PGA are produced on carboxylation?
| a) 3 |
| b) 1 |
| c) 2 |
| d) 4 |
Answer: c
Explanation: 3-PGA or 3-phosphoglyceric acid is the product of carboxylation. It is a 3-carbon organic acid. RuBP or ribulose bisphosphate undergoes carboxylation to produce two molecules of 3-PGA or 3-phosphoglyceric acid.
34. Which of these statements is false about reduction in the Calvin cycle?
| a) It is the third step of the cycle |
| b) It leads to the formation of glucose |
| c) It utilizes NADPH for reduction |
| d) It utilizes ATP for phosphorylation |
Answer: a
Explanation: Reduction is the second step of the Calvin cycle. It results in the formation of glucose. Reduction utilizes NADPH for reduction and ATP for phosphorylation which results in the production of glucose.
35. How many turns of the Calvin cycle are required for the formation of 3 glucose molecules?
| a) 15 |
| b) 16 |
| c) 12 |
| d) 18 |
Answer: d
Explanation: The formation of one molecule of glucose requires the fixation of 6 carbon dioxide molecules and hence six turns of the Calvin cycle. Hence, 3 glucose molecules will require 18 turns of the cycle.
36. Which of these molecules is regenerated during the Calvin cycle?
| a) NADPH |
| b) ATP |
| c) RuBP |
| d) CO2 |
Answer: c
Explanation: Regeneration is the third and final step of the Calvin cycle. In this step, the CO2 acceptor molecule RuBP or ribulose bisphosphate is regenerated. The regenerated RuBP is again used for the next Calvin cycle.
37. How many molecules of NADPH are required for each Calvin cycle?
| a) 3 |
| b) 1 |
| c) 4 |
| d) 2 |
Answer: d
Explanation: For every carbon dioxide molecule used up in the Calvin cycle, 2 molecules of NADPH are required. Six cycles are required to produce one glucose molecule; hence 12 NADPH molecules are required to produce one molecule of glucose.
38. How many molecules of ATP are required for each Calvin cycle?
| a) 1 |
| b) 2 |
| c) 3 |
| d) 4 |
Answer: c
Explanation: For every carbon dioxide molecule used up in the Calvin cycle, 3 molecules of ATP are required. Six cycles are required to produce one glucose molecule; hence 18 ATP molecules are required to produce one molecule of glucose.
39. How many molecules of NADP are produced as a result of six Calvin cycles?
| a) 9 |
| b) 18 |
| c) 12 |
| d) 24 |
Answer: c
Explanation: For every carbon dioxide molecule used up in the Calvin cycle, 2 molecules of NADPH are required. Hence, 2 molecules of NADP are produced. For six Calvin cycles, 12 molecules of NADP are produced.
40. How many molecules of ADP are produced as a result of six Calvin cycles?
| a) 18 |
| b) 24 |
| c) 12 |
| d) 32 |
Answer: a
Explanation: For every carbon dioxide molecule used up in the Calvin cycle, 3 molecules of ATP are required. Hence, 3 molecules of ADP are produced. For six Calvin cycles, 18 molecules of ADP are produced.
41. How many molecules of carbon dioxide are required in the Calvin cycle to produce 3 molecules of glucose?
| a) 9 |
| b) 18 |
| c) 6 |
| d) 15 |
Answer: b
Explanation: To make one molecule of glucose six molecules of carbon dioxide are required. Hence, six cycles of the Calvin cycle are required. To make three molecules of glucose, 18 molecules of carbon dioxide are required.
42. Which of these is not a characteristic of C4 plants?
| a) Toleration of higher temperatures |
| b) Response to high light intensities |
| c) Greater productivity of biomass |
| d) Photorespiration |
Answer: d
Explanation: C4 plants show some special adaptations to survive extreme climate, such as tolerance of higher temperatures, response to high intensity lights, lack of photorespiration and greater productivity of biomass.
43. What is the special leaf anatomy in C4 plants known as?
| a) Mesophyll anatomy |
| b) Vascular anatomy |
| c) Kranz anatomy |
| d) Calvin anatomy |
Answer: c
Explanation: C4 plants have a special type of anatomy of the leaves. This is known as Kranz anatomy. It is characterized by the presence of large cells around the vascular bundles known as bundle sheath cells.
44. What is the arrangement of cells in plants showing Kranz anatomy?
| a) Tapered |
| b) Irregular |
| c) Wreath |
| d) Triangular |
Answer: c
Explanation: C4 plants have a special type of anatomy of the leaves. This is known as Kranz anatomy. It is characterized by the presence of large cells around the vascular bundles in the form of a wreath.
45. Which of the following is false regarding the bundle sheaths of plants showing Kranz anatomy?
| a) They lack chloroplasts |
| b) They are layered around the vascular bundles |
| c) They have thick walls |
| d) They lack intercellular spaces |
Answer: a
Explanation: In plants showing Kranz anatomy, the bundle sheaths surrounding the vascular bundles have characteristics such as thick walls, a large number of chloroplasts and no intercellular spaces. They are layered around the vascular bundles.
Photosynthesis In Higher Plants MCQ For NEET
46. Which of these is a C4 plant?
| a) Wheat |
| b) Maize |
| c) Rice |
| d) Cotton |
Answer: b
Explanation: C4 plants have a special type of anatomy of the leaves. This is known as Kranz anatomy, characterized by the presence of large cells around the vascular bundles. Wheat, rice and cotton are C3 plants.
47. Which of these features cannot help us differentiate between C3 and C4 plants?
| a) Presence of Kranz anatomy |
| b) Presence of photorespiration |
| c) Presence of chloroplasts |
| d) Presence of bundle sheath |
Answer: c
Explanation: C4 plants show Kranz anatomy in which bundle sheath cells surrounds the vascular bundles. They lack photorespiration and show presence of bundle sheaths. However, chloroplasts are present in both types of plants.
48. Which of these is the primary carbon dioxide acceptor in the Hatch and Slack pathway?
| a) PEP |
| b) PGA |
| c) OAA |
| d) PEPcase |
Answer: a
Explanation: The primary carbon dioxide acceptor in the Hatch and Slack pathway is PEP or phosphoenol pyruvate. PEP is present in the mesophyll cells. Phosphoenol pyruvate is a 3-carbon molecule.
49. Which of these are not present in mesophyll cells?
| a) OAA |
| b) PEP carboxylase |
| c) PEPcase |
| d) RuBisCO |
Answer: d
Explanation: The mesophyll cells contain PEP or phosphoenol pyruvate, which is the primary carbon dioxide acceptor. It also contains the enzyme PEPcase or PEP carboxylase. However, it lacks RuBisCO.
50. Which of these is the C4 acid?
| a) PEP |
| b) PGA |
| c) OAA |
| d) RuBisCO |
Answer: c
Explanation: The C4 acid has 4 carbon atoms. It is oxaloacetic acid or OAA. It is the first stable product of carbon dioxide fixation in C4 plants. PGA is a 3-carbon organic acid while PEP also has 3 carbon atoms.
51. Which of these is not a 4-carbon compound?
| a) Aspartic acid |
| b) OAA |
| c) Malic acid |
| d) PGA |
Answer: d
Explanation: Oxaloacetic acid or OAA is the first stable product of carbon dioxide fixation in C4 plants. OAA, along with malic acid and aspartic acid are 4-carbon compounds. However, PGA is a 3-carbon compound.
52. Which enzyme is a major component of the bundle sheath cells?
| a) PEPcase |
| b) PEP |
| c) RuBisCO |
| d) PEP carboxylase |
Answer: c
Explanation: PEP or phosphoenol pyruvate is not an enzyme. PEPcase, also known as PEP carboxylase is not present in bundle sheath cells. However, bundle sheath cells are rich in the enzyme RuBisCO.
53. Which of these is common to C3 and C4 plants?
| a) OAA |
| b) PGA |
| c) Calvin cycle |
| d) Photorespiration |
Answer: c
Explanation: In C3 plants, the first stable product of carbon dioxide fixation is 3-PGA or 3-phosphoglyceric acid. For C4 plants, it is OAA or oxaloacetic acid. C4 plants lack photorespiration. The Calvin cycle is common to both.
54. In which of these cells does the Calvin pathway occur in C3 plants?
| a) Mesophyll cells |
| b) Bundle sheath cells |
| c) Epidermal cells |
| d) Sieve cells |
Answer: a
Explanation: The Calvin pathway occurs in C3 plants in the mesophyll cells. In such plants, the first stable product of carbon dioxide fixation is 3-PGA or 3-phosphoglyceric acid. In C4 plants, the Calvin cycle occurs in bundle sheath cells.
55. In which of these cells does the Calvin pathway occur in C4 plants?
| a) Mesophyll cells |
| b) Bundle sheath cells |
| c) Epidermal cells |
| d) Sieve cells |
Answer: b
Explanation: The Calvin pathway occurs in C4 plants in the bundle sheath cells. The bundle sheath cells are a characteristic of C4 plants. They surround the vascular bundles in layers. It is the site of Calvin cycle.
56. The electron transport system occurs in _____
| a) Thylakoid membrane |
| b) Stroma |
| c) Cytosol |
| d) Mitochondria |
Answer: a
Explanation: It is in the thylakoid membrane, in which the electron transport system occurs. Each thylakoid membrane is a closed compartment that gets protons from stroma by the b6 or f complex. Also, thylakoid membrane is impermeable to protons.
57. The first electron acceptor in photosystem 1 is _____
| a) Plastoquinone |
| b) Cytochrome b |
| c) A Fe-S protein |
| d) Water |
Answer: c
Explanation: The first electron acceptor in photosystem 1 is a Fe-S protein. It is a stable complex of iron and sulfur atoms bonded to a protein. It primarily accepts the electrons and passes onto NADP+.
58. How much hydrogen protons are released by twelve water molecules?
| a) 48 |
| b) 6 |
| c) 12 |
| d) 24 |
Explanation: By understanding the photolysis equation, one water molecule gives 2 hydrogen protons. So, 12 water molecules will give 24 hydrogen protons.
59. The name of the scheme given to the transport of electrons is called as _______
| a) Z scheme |
| b) W scheme |
| c) Y scheme |
| d) E scheme |
Answer: a
Explanation: The scheme is called Z-scheme. This name was given due to the shape of the sequence. The transfer of electrons from PS II to NADP+ produces this scheme when the carries are placed in the order of the redox potential scale.
60. _____ is the only product in cyclic photophosphorylation.
| a) ADP |
| b) ATP |
| c) Hydrogen |
| d) Oxygen |
Answer: b
Explanation: ATP is the only product in cyclic photophosphorylation. PS II is not involved in this process. So, there will be no creation of reducing power i.e. NADPH + H+. And the only source of energy is ATP in cyclic photophosphorylation.
Photosynthesis In Higher Plants Class 11 MCQ
61. In PS II, the last electron acceptor is ______
| a) Plastocyanin |
| b) Ferredoxin |
| c) Cytochrome b6 |
| d) Cytochrome b12 |
Answer: a
Explanation: Plastocyanin, which is a Cu protein is the last electron acceptor in PS II. It receives the electrons from cytochrome f and passes onto PS I. This is all based on non-cyclic photophosphorylation reaction.
62. _______ accepts the electrons from Pheophytin.
| a) Cytochrome f |
| b) Cytochrome d |
| c) Plastoquinone |
| d) Ferredoxin |
Answer: cExplanation: Plastoquinone (PQ) is an electron carrier. It accepts the electrons from pheophytin. PQ gets 2 electrons and passes these to cytochrome b6. It also plays a major role in light-dependent reactions.
63. The electrons produced in the photolysis of water enters ______
| a) Fe-S protein |
| b) PS II |
| c) Plastocyanin |
| d) Cytochrome a |
Answer: b
Explanation: During the photolysis of water, two electrons are produced. These electrons enter into PS II and it transfers the electron to Pheophytin (the primary electron acceptor). These electrons mainly help during reduction reactions.
64. The process by which the pH gradient across the membrane provides energy for the synthesis of ATP is called as ______
| a) Phosphorylation |
| b) Transfusion |
| c) Diffusion |
| d) Chemiosmosis |
Answer: d
Explanation: There is a pH gradient across the thylakoid membrane, which provides a proton motive force. This creates chemical potential energy for the production of ATP from ADP and inorganic phosphate is called chemiosmosis. Peter Mitchell proposed this theory.
65. In which process does carbon dioxide join photosynthesis?
| a) Oxidation |
| b) PS I |
| c) Dark reaction |
| d) Reduction |
Answer: c
Explanation: Carbon dioxide is entering the photosynthetic pathway through dark reaction. RuBP reacts with CO2 to form the first unstable carbon compound. So, here 6 molecules of CO2 are required to start dark reaction.
66. The reaction center in the light-harvesting complex is formed by _____
| a) Chlorophyll b |
| b) Grana |
| c) Chlorophyll e |
| d) A single chlorophyll a molecule |
Answer: d
Explanation: The reaction center in the light-harvesting complex is formed by a single “chlorophyll a” molecule. This chlorophyll a molecule has the capability to absorb different wavelengths of light energy. It is mainly known for the process called photoionization of chlorophyll.
67. Which of the following is not related to the light reaction?
| a) Also called Photochemical phase |
| b) Light absorption |
| c) Electron transport |
| d) Water splitting |
Answer: c
Explanation: Electron transport is not related to light reaction. It is because light reaction is mainly based on photochemical processes like light absorption, water splitting, the formation of ATP and NADPH, etc. where electron transport is not included.
68. How many light-harvesting systems are there in light reaction?
| a) Two |
| b) One |
| c) Three |
| d) Four |
Answer: a
Explanation: The photosynthetic pigments are organized into two groups of light-harvesting systems. They are mainly composed of many pigments bonded to proteins. These light-harvesting systems are present within PS I and PS II.
69. Which is the site of dark reaction?
| a) Matrix |
| b) Stroma |
| c) Cytochrome |
| d) Roots |
Answer: b
Explanation: Stroma is the site of dark reaction which is an enzymatic as well as light-independent reaction. Stroma is a colorless fluid that surrounds the grana and thylakoids. It also contains other sub organelles and daughter cells that supports dark reaction.
70. Which pigment is absent in each photosystem?
| a) One molecule of chlorophyll a |
| b) Two molecules of chlorophyll b |
| c) One molecule of chlorophyll b |
| d) One molecule of xanthophyll |
Answer: a
Explanation: One molecule of chlorophyll a is absent in each photosystem forming a light-harvesting system also known as the antenna. These pigments make photosynthesis more efficient. The reaction center is formed by this one molecule of chlorophyll a.
71. PS I is the photosystem present only in _______ photosynthesis.
| a) Amoeba |
| b) Bacterial |
| c) Fungal |
| d) Plant |
Answer: b
Explanation: PS I is the only photosystem present in bacterial photosynthesis. It lacks PS II since it is having less complexity for photosynthesis, they only require one photosystem.
72. Which of these cannot help us differentiate between C3 and C4 plants?
| a) Carbon dioxide acceptor molecule |
| b) Presence of Kranz anatomy |
| c) Photorespiration |
| d) Number of chloroplasts |
Answer: d
Explanation: C4 plants differ in various ways from C3 plants. They show Kranz anatomy. C4 plants lack photorespiration but C3 plants have a high rate of photorespiration and they do not show Kranz anatomy.
73. What is the first step of the Calvin pathway?
| a) Regeneration |
| b) Reduction |
| c) CO2 fixation |
| d) Synthesis of sugar |
Answer: c
Explanation: The first step of the Calvin pathway or the Calvin cycle is the carbon dioxide fixation step. Carbon dioxide is fixed with the help of a carbon dioxide acceptor molecule, such as RuBP or PEP.
74. Which of these take place in the first step of the Calvin pathway?
| a) 3 molecules of 2PGA are formed |
| b) RuBisCO combines with CO2 |
| c) RuBP and CO2 give PGA |
| d) RuBP acts as a catalyst |
Answer: c
Explanation: The first step of the Calvin pathway or the Calvin cycle is the carbon dioxide fixation step. The carbon dioxide acceptor molecule RuBP combines with carbon dioxide to give 2 molecules of 3PGA.
75. Which of these is true regarding carbon dioxide fixation?
| a) RuBP and CO2 give PGA |
| b) RuBisCO combines with CO2 |
| c) 3 molecules of 2PGA are formed |
| d) RuBP acts as a catalyst |
Answer: a
Explanation: The first step of the Calvin pathway is the carbon dioxide fixation step. The carbon dioxide acceptor molecule RuBP combines with carbon dioxide to give 2 molecules of 3PGA with RuBisCO as the catalyst.
Photosynthesis In Higher Plants NEET MCQ
76. Complete the reaction.
RuBP + CO2 →
| a) 3 × 3PGA |
| b) 2 × 3PGA |
| c) 2 × 3PGA + RuBisCO |
| d) 3 × 3PGA + RuBisCO |
Answer: b
Explanation: The given reaction is that of the first step of the Calvin cycle, carbon dioxide fixation. RuBP combines with carbon dioxide to form two molecules of 3PGA. RuBisCO is an enzyme that catalyses the reaction.
77. What is the most abundant enzyme in the world?
| a) Papain |
| b) Alpha amylase |
| c) RuBisCO |
| d) Horse radish peroxidase |
Answer: c
Explanation: RuBisCO or Ribulose-1,5-bisphosphate carboxylase oxygenase is the most abundant enzyme in the world. It catalyses the formation of 3PGA from RuBP and carbon dioxide.
78. What does the name RuBisCO imply?
| a) Its active site can bind to oxygen and carbon dioxide |
| b) It leads to the combination of oxygen and carbon dioxide |
| c) It uses carbon and oxygen to breakdown sugar |
| d) It uses carbon and oxygen to breakdown RuBP |
Answer: a
Explanation: RuBisCO or Ribulose-1,5-bisphosphate carboxylase oxygenase is the most abundant enzyme in the world. The active site of RuBisCO can bind to both oxygen and carbon dioxide. It has a higher affinity for carbon dioxide.
79. What factor determines the binding of carbon dioxide to the active site of RuBisCO?
| a) Intensity of sunlight |
| b) Number of chloroplasts |
| c) Opening and closing of stomata |
| d) Relative O2 and CO2 concentration |
Answer: d
Explanation: The active site of RuBisCO can bind to both oxygen and carbon dioxide. It has a higher affinity for carbon dioxide. Hence, the relative concentrations of carbon dioxide and oxygen decide the binding of carbon dioxide.
80. Why is carbon dioxide fixation decreased in some C3 plants?
| a) Phosphoglycerate formation |
| b) Unavailability of RuBP |
| c) Oxygen binds to RuBisCO |
| d) Oxygen binds to RuBP |
Answer: c
Explanation: The active site of RuBisCO can bind to both oxygen and carbon dioxide. When oxygen binds to RuBisCO, carbon dioxide fixation is reduced as the active site of RuBisCO is not able to bind to carbon dioxide.
81. What is formed when the active site of RuBisCO binds to oxygen?
| a) ATP |
| b) OAA |
| c) PGA |
| d) Phosphoglycolate |
Answer: d
Explanation: When oxygen binds to RuBisCO, carbon dioxide fixation is reduced as the active site of RuBisCO is not able to bind to carbon dioxide. Phosphoglycerate and phosphoglycolate are formed instead.
82. Which of these is not true regarding photorespiration?
| a) ATP is not synthesized |
| b) 1 molecule of phosphoglycerate is formed |
| c) 1 molecule of PGA is formed |
| d) The active site of RuBisCO binds to oxygen |
Answer: c
Explanation: During the process of photorespiration, the active site of RuBisCO binds to oxygen. ATP and sugars are not formed. Instead of PGA, 1 molecule of phosphoglycerate and phosphoglycolate are formed.
83. Which of these are synthesized during photorespiration?
| a) NADPH |
| b) ATP |
| c) CO2 |
| d) Sugars |
Answer: c
Explanation: During the process of photorespiration, the active site of RuBisCO binds to oxygen. ATP is not formed but is utilized. NADPH and sugars are not synthesized. Carbon dioxide is released as a result of this process.
84. Which of these is a 2-carbon molecule?
| a) Phosphoglycolate |
| b) OAA |
| c) PGA |
| d) Malic acid |
Answer: a
Explanation: Phosphoglycolate is a 2-carbon compound formed during the process of photosynthesis. Malic acid and oxaloacetic acid (OAA) are 4-carbon compounds while PGA is a 3-carbon compound.
85. Why is the productivity of C4 plants better than that of C3 plants?
| a) C4 plants show Kranz anatomy |
| b) C4 plants lack photorespiration |
| c) C4 plants show high phosphoglycerate formation |
| d) C4 plants show high phosphoglycolate formation |
Answer: b
Explanation: The productivity of C4 plants better than that of C3 plants as C4 plants lack photorespiration. C4 plants do not show phosphoglycerate and phosphoglycolate formation, unlike C3 plants.
Photosynthesis Questions For NEET
86. The process in which green plants synthesize organic food by utilizing carbon dioxide and water as raw materials, in the presence of sunlight is called as ______
| a) Respiration |
| b) Food synthesis |
| c) Photosynthesis |
| d) Light synthesis |
Answer: c
Explanation: The process in which green plants synthesize organic food by utilizing carbon dioxide and water as raw materials, in the presence of sunlight is called Photosynthesis. This is the pure definition. Oxygen is a byproduct which is advantageous for all living organisms.
87. Which is correct regarding photosynthesis?
| a) Carbon dioxide is obtained from the atmosphere |
| b) Water is absorbed from the soil through the stem system |
| c) Sunlight is trapped by pigments called xanthophyll |
| d) Chlorophyll absorbs green light |
Answer: a
Explanation: The carbon dioxide is obtained from the atmosphere whereas water is absorbed from the soil through the root system. Sunlight is trapped by pigments present in the leaf called chlorophyll and it absorbs violet, blue, and red lights and reflects green light.
88. The half leaf experiment showed that _____ is important for photosynthesis.
| a) O2 |
| b) CO2 |
| c) Sunlight |
| d) Chlorophyll |
Answer: b
Explanation: This experiment showed that CO2 is important for photosynthesis. It was experimented by a scientist named Molls. It was named half leaf experiment because half of the leaf was enclosed in a test tube.
89. A compound was used in the half leaf experiment to absorb CO2. This compound is ______
| a) KMNO4 |
| b) HCl |
| c) NaOH |
| d) KOH |
Answer: d
Explanation: KOH was the compound used in half leaf experiment to absorb CO2. The part of the leaf enclosed in test tube contained some KOH soaked cotton while the other half was exposed to air. KOH has got the capability to absorb CO2.
90. Which of the following is not an accessory pigment?
| a) Chlorophyll a |
| b) Bacteriochlorophyll |
| c) Chlorophyll b |
| d) Phycobilin |
Answer: a
Explanation: Chlorophyll is not an accessory pigment as it the chief pigment of the chloroplast. Chlorophyll b, xanthophyll, and carotenoids are accessory pigments. Bacteriochlorophyll and phycobilin are other pigments present in leaves.
91. Which is the correct color matching in chromatogram?
| a) Chlorophyll a – yellow-green |
| b) Chlorophyll b – yellow-orange |
| c) Xanthophyll – yellow |
| d) Carotenoids – bright or blue-green |
Answer: c
Explanation: Xanthophyll shows a yellow color. Chlorophyll a shows bright or blue – green color whereas chlorophyll b shows yellow – green. Carotenoids show varying color from yellow to yellow – orange.
92. Which of the following is the main function of carotenes?
| a) Not an accessory pigment |
| b) Photooxidation |
| c) Helps in photosynthesis |
| d) Helps in transpiration |
Answer: b
Explanation: They just have mainly two functions. That is photooxidation which means they produce oxygen due to light. Also, it helps the plant from photodamage i.e. the plant gets protected from excess heat. Carotene is also known as an accessory pigment.
93. Methyl group is mainly present in which photosynthetic pigment?
| a) Chlorophyll b |
| b) Xanthophyll |
| c) Carotenoids |
| d) Chlorophyll a |
Answer: d
Explanation: Methyl group CH3 is mainly present in chlorophyll a. But in chlorophyll b, it has an aldehyde group in the C7 position. Chlorophyll a and b structure mainly differs in the substituent of porphyrin.
94. Who found out that the pigment chlorophyll is found in the chloroplast in plant cells?
| a) Robert Hill |
| b) Hugo de Vries |
| c) Julius Von Sachs |
| d) C. Van Neil |
Answer: c
Explanation: Julius Von Sachs found out that the pigment chlorophyll is present in chloroplast. Von Sachs in his experiment found out glucose stored in the form of starch. This led to the discovery of pigment chlorophyll in the chloroplast.
95. What is the empirical formula of chlorophyll b?
| a) C55H70O6N4Mg |
| b) C55H72O5N4Mg |
| c) C55H79O7N4Mg |
| d) C55H80O6N5Mg |
Answer: a
Explanation: The empirical formula of chlorophyll b is C55H70O6N4Mg. They have 55 atoms of carbon, 70 atoms of hydrogen, 6 atoms of oxygen, 4 atoms of nitrogen and one atom magnesium. They are very microscopic and officially an accessory pigment.
96. How many numbers of chlorophyll are present in a photosynthetic unit?
| a) 100 – 150 |
| b) 90 |
| c) 200 – 250 |
| d) 300 – 350 |
Answer: c
Explanation: In a photosynthetic unit, 200 – 250 number of chlorophylls are present. They are embedded in the thylakoids of chloroplast. It differs for different plant species as in algae, it is only 100 in number. The number of chlorophylls is based on their requirement and function.
97. Which is false regarding chlorophyll a and b?
| a) Chlorophyll b is an accessory pigment |
| b) Chlorophyll is the main chief pigment |
| c) Chlorophyll a is more than chlorophyll b |
| d) Both are present in equal proportion |
Answer: d
Explanation: In chloroplast, chlorophyll-a is more than chlorophyll b. They are not present in equal proportion. Since chlorophyll-a is the main chief pigment in photosynthesis, it is more in number. Chlorophyll b is less in number since it is only an accessory pigment.
98. Where does the photosynthesis actually take place?
| a) Leaves |
| b) Chloroplast |
| c) Flowers |
| d) Root |
Answer: b
Explanation: The photosynthesis actually takes place in an organelle called chloroplast. They are found in the cytoplasm of plant cells. The main feature of the chloroplast is that they are able to produce food for plants.
99. Where does photosynthesis take place in C3 plants?
| a) C3 station |
| b) Arthroplasty |
| c) Mesosomes |
| d) Mesophyll cells |
Answer: d
Explanation: The photosynthesis takes place in the mesophyll cells of C3 plants. They are actually ground tissue found in the middle of the plants. Their main function is to fix carbon and perform photosynthesis. 95% of all temperate plants are C3 plants.
100. Chloroplasts are also known as _____________
| a) Photosynthetic factories |
| b) Food makers |
| c) Color factories |
| d) Lifer giver |
Answer: a
Explanation: Chloroplast is mainly known as photosynthetic factories. This is because all the reactions based on photosynthesis takes place within the chloroplast. Also, they convert light energy into sugar or glucose in the form of starch.
101. Which part of chloroplast contains all the water-soluble enzymes?
| a) Lamella |
| b) Stroma |
| c) Matrix |
| d) Chlorophyll |
Answer: c
Explanation: Matrix is the part which contains all the water-soluble enzymes. Chloroplast encloses a fluid-filled space called stroma and this fluid is called the matrix. These enzymes are stored in the matrix to make it available for dark reactions.
102. The stroma contains a number of _____ made up of disc-like ______
| a) grana, thylakoids |
| b) grana, stroma |
| c) thylakoids, grana |
| d) stroma, grana |
Answer: a
Explanation: The stroma actually contains a number of grana made up of disc-like thylakoids. Grana and thylakoids are the main sites of light reaction. A stack of thylakoid discs together forms a granum (plural of grana). Grana ranges from 10 to almost 100 in number.