TOP 100+ Respiration In Plants NEET Questions and Answers

These Respiration In Plants NEET Questions and Answers are composed by our livemcqs team speacially for NEET, AIIMS and other Medical Entrance aspirents. These Respiration In Plants MCQ and Answers covers the all concepts of the Chapter 14 of Class 11 Biology. You can download these Questions by clicking the Link “Respiration In Plants MCQ For NEET PDF” given below.

Respiration In Plants NEET Questions

1. What is aerobic respiration?

a) Partial oxidation of glucose
b) Incomplete oxidation of glucose
c) Complete oxidation of organic substances
d) Complete oxidation of only glucose

Answer: c

Explanation: Aerobic respiration is the complete oxidation of organic substances which occur in the presence of oxygen. It is an energy yielding process as a large amount of energy in the form of ATP is released. Water and carbon dioxide are also released as its by-products.

2. Where does aerobic respiration usually takes place?

a) Lower vertebrates
b) Higher organisms
c) Prokaryotes
d) Only unicellular eukaryotes

Answer: b

Explanation: Aerobic respiration is most common in higher organisms. In eukaryotes, the steps of aerobic respiration take place within the mitochondria and this requires oxygen.

3. What is the efficiency of aerobic respiration?

a) More than 75%
b) Approximately 45%
c) Less than 20%
d) 99%

Answer: b

Explanation: The efficiency of aerobic respiration is approximately 45%. For aerobic respiration, the final product of glycolysis is transported from the cytoplasm into the mitochondria.

4. Where does the second process of aerobic respiration take place?

a) In the lumen of mitochondria
b) In the matrix of mitochondria
c) In the inner membrane of mitochondria
d) In the cristae of mitochondria

Answer: c

Explanation: The two stages of aerobic respiration are Kreb’s cycle and electron transport system. The first process takes place in the matric of mitochondria while the second process takes place in the inner membrane of mitochondria in eukaryotes.

5. How many CO2 molecules are left during the complete oxidation of pyruvate?

a) One
b) Two
c) Five
d) Three

Answer: d

Explanation: The complete oxidation of pyruvate by the stepwise removal of all the hydrogen atoms takes place while leaving three molecules of Carbon-dioxide.

6. Which of the following is a crucial event in aerobic respiration?

a) Simultaneous synthesis of ATP
b) Synthesis of ethanol and water
c) Complete oxidation of methanol
d) Complete oxidation of carbon-dioxide

Answer: a

Explanation: The crucial events in aerobic respiration are the complete oxidation of pyruvate and the passing on of the electrons removed as a part of the hydrogen atoms to molecular oxygen with the simultaneous synthesis of ATP.

7. Which of the following participates in the reaction catalysed by pyruvic dehydrogenase?

a) Carbon dioxide
b) Water
c) Ethanol
d) Coenzyme A

Answer: d

Explanation: The reaction catalysed by pyruvic dehydrogenase requires the participation of several coenzymes that include NAD+ and Coenzyme A.

8. How many molecules of NADH are produced by the metabolism of pyruvic acid?

a) One
b) Two
c) Three
d) Four

Answer: b

Explanation: During the process, two molecules of NADH are produced from the metabolism of two molecules of pyruvic acid i.e. produced from one glucose molecule during glycolysis.

9. Who discovered the Tricarboxylic acid cycle?

a) Hans Krebs
b) Ernst Haeckel
c) Louis Pasteur
d) Charles Darwin

Answer: a

Explanation: Tricarboxylic acid cycle, more commonly known as Kreb’s cycle was elucidated by Hans Krebs who first discovered it in the flight muscles of pigeon.

10. The TCA cycle starts with the condensation of which of the following compounds?

a) Sucrose
b) Acetyl group
c) Ethanol
d) Pyruvate

Answer: b

Explanation: The TCA cycle starts with the condensation of acetyl group. It reacts with oxaloacetic acid and water and forms citric acid. This reaction is catalysed by the enzyme citrate synthase and a molecule of CoA is released. Further, citrate is isomerised to isocitrate with the help of isomerase enzyme.

11. How many steps of decarboxylation lead to the formation of ketoglutaric acid?

a) One
b) Three
c) Two
d) Seven

Answer: c

Explanation: Two steps of decarboxylation leads to the formation of ketoglutaric acid. When citric acid is formed in the cycle, it then forms cis-acotinic acid and then isocitric acid. Isocitric acid further forms oxalosuccinic acid which finally forms ketoglutaric acid in the presence of oxalosuccinate decarboxylase enzyme.

12. Which of the following compounds is the first member of the TCA cycle?

a) Oxaloacetic acid
b) α-ketoglutaric acid
c) Succinic acid
d) Malic acid

Answer: a

Explanation: Oxaloacetic acid is the first member of the TCA cycle. The continued oxidation of acetyl CoA via the TCA cycle requires the continued replenishment of Oxaloacetic acid.

13. What is the full form of SLP?

a) Subgeneric Level of Phosphorylation
b) Subcutaneous Level Photophosphorylation
c) Substrate Level Phosphorylation
d) Substrate Level Pyruvatisation

Answer: c

Explanation: SLP stands for Substrate Level Phosphorylation. During the conversion of succinyl-CoA to succinic acid, a molecule of GTP is synthesised. This is substrate-level phosphorylation.

14. How many points are there in the TCA cycle where NAD+ is reduced?

a) One
b) Two
c) Three
d) Four

Answer: c

Explanation: There are three points in the TCA cycle where NAD+ is reduced to NADH + H+ and one point where FAD+ is reduced to FADH2. In a coupled reaction GTP is converted to GDP with the simultaneous synthesis of ATP from ADP.

15. Which of the following points are not necessary for the TCA to run continuously?

a) Replenishment of Oxaloacetic acid
b) Regeneration of NAD+
c) Regeneration of FAD+
d) Regeneration of malic acid

Answer: d

Explanation: The points which are necessary for the TCA cycle to run continuously are:
i. Continued replenishment of Oxaloacetic acid
ii. Regeneration of NAD+ from NADH
iii. Regeneration of FAD+ from FADH2

Respiration In Plants MCQ and Answers

16. What is the full form of ETS?

a) Electrolyte Transport Serum
b) Electrolyte Tissue System
c) Electron Transport System
d) Electron Transmission System

Answer: c

Explanation: ETS stands for Electron Transport System. It is the metabolic pathway where the products of glycolysis and Kreb’s cycle are phosphorylated to form ATP.

17. What is the use of ETS?

a) To release and utilise energy
b) To store energy
c) To transfer energy to the surroundings
d) To take energy from the surroundings

Answer: a

Explanation: The steps in the respiratory process in the ETS are to release and utilise the energy stored in NADH + H+ and FADH2. This system is present in the inner mitochondrial membrane.

18. Where are the electrons passed in ETS?

a) Oxygen
b) Water
c) Carbon
d) Nitrogen

Answer: a

Explanation: In ETS, NADH and FADH2 are oxidise through various steps and the electrons from this process are passed on to Oxygen resulting in the formation of water.

19. Which complex oxidises the electrons produced by NADH?

a) Complex I
b) Complex II
c) Complex V
d) Complex IV

Answer: a

Explanation: Complex I oxidises the electrons produced by NADH. Complex I is also known as NADH dehydrogenase. The electrons from the oxidation of NADH to NAD+ are passed onto the FMN complex which is located in the inner mitochondrial membrane.

20. What is reduced Ubiquinone called as?

a) Ubiquinone
b) Ubiquity
c) Ubiquinol
d) Ubiquinal

Answer: c

Explanation: The reduced ubiquinone which is also known as Ubiquinol is oxidised with the transfer of electrons to cytochrome c via cytochrome bc1 complex or Complex III.

21. Cytochrome c acts a carrier between which of the two complexes?

a) Complex I and Complex II
b) Complex II and Complex III
c) Complex III and Complex IV
d) Complex IV and Complex V

Answer: c

Explanation: Cytochrome c is a small protein that is attached to the outer surface of the inner membrane and acts as a mobile carrier for transfer of electrons between Complex III and Complex IV.

22. How many copper centres are present in Complex IV?

a) One
b) Two
c) Three
d) Four

Answer: b

Explanation: Complex IV refers to cytochrome c oxidase complex containing cytochromes a and a3, and two copper centres. The electrons in ETS pass from one carrier to another via complex I to IV.

23. The number of ATP molecules synthesised depends upon which of the following?

a) Nature of electron donor
b) Nature of electron acceptor
c) Nature of proton donor
d) Nature of atom

Answer: a

Explanation: The number of ATP molecules synthesised depends on the nature of the electron donor. Oxidation of one molecule of NADH gives rise to three molecules of ATP, while that of one molecule of FADH2 produces two molecules of ATP.

24. Which of the following is the final hydrogen acceptor?

a) Phosphorous
b) Carbon
c) Nitrogen
d) Oxygen

Answer: d

Explanation: Oxygen acts as the final hydrogen acceptor. Oxygen is present in the matrix of the mitochondria and finally accepts the protons and forms water molecules. Oxygen is the molecule which drives the whole process of oxidative phosphorylation.

25. Which of the following energy is utilised for the production of the proton gradient in ETS?

a) Energy of Oxygen
b) Energy of Hydrogen
c) Energy of Phosphorous
d) Energy of Oxidation-Reduction

Answer: d

Explanation: Unlike photophosphorylation, where it is the light energy that is utilised for the production of proton gradient required for phosphorylation, in respiration, it is the energy of the oxidation-reduction utilised for the same process. It is for this reason that the process is called Oxidative phosphorylation.

26. Which of the following complexes in ETS are involved in the transport of protons?

a) Complex I
b) Complex II
c) Complex V
d) Complex IV

Answer: c

Explanation: In the electron transport system, Complex I, II, III and IV are related to the transport of only electrons in the mitochondria. Complex V is the only complex in ETS which is involved in proton transport.

27. How many major components are there in Complex V of ETS?

a) One
b) Two
c) Three
d) Four

Answer: b

Explanation: The energy released during the electron transport system is utilised in synthesising ATP with the help of ATP synthase-Complex V. This complex consists of two major components F1 and F0.

28. What kind of protein is F1 that is present in Complex V?

a) Peripheral protein
b) Embedded protein
c) Integral protein
d) Membrane less protein

Answer: a

Explanation: The F1 headpiece that is present in the Complex V is a peripheral membrane protein complex and contains the site for synthesis of ATP from ADP and inorganic phosphate.

29. What kind of compound is F0 particle?

a) Peripheral protein
b) Cutaneous protein
c) Embedded protein
d) Integral protein

Answer: d

Explanation: Fo is an integral membrane protein complex that forms the channel through which protons across the inner membrane. It is a component of Complex V of ETS.

30. For each ATP produced, how many protons pass through the intermembrane space?

a) One
b) Two
c) Three
d) Four

Answer: b

Explanation: The passage of protons through the channel is coupled to the catalytic site of the F1 component for the production of ATP. For each ATP produced, two protons pass through the F0 from the intermembrane space to the matrix down the electrochemical proton gradient.

Respiration NEET Questions

31. Which of the following is the favoured substance for respiration?

a) Sucrose
b) Lactose
c) Glucose
d) Mannose

Answer: c

Explanation: Glucose is the favoured substrate for respiration because glucose is a carbohydrate and is readily available in the cells through the food that cell intakes. It also releases a large amount of energy on its oxidation.

32. For the fats to be respired, what are they broken into?

a) Glycerol and fatty acids
b) Glycerol and ethanol
c) Fatty acids only
d) Glycerol only

Answer: a

Explanation: Fats would need to be broken down into glycerol and fatty acids first. If fatty acids were to be respired they would first be degraded to acetyl CoA and enter the pathway.

33. Which of the following are responsible for the degradation of proteins?

a) Lipases
b) DNase
c) RNase
d) Proteases

Answer: d

Explanation: Proteases are the enzymes which are responsible for the degradation of proteins. These enzymes break the bonds between the proteins and release amino acids which then enter the respiratory pathway.

34. Which pathway was respiration traditionally considered as?

a) Anabolic pathway
b) Catabolic pathway
c) Amphibolic pathway
d) Bolic pathway

Answer: b

Explanation: Since respiration involves the breakdown of substrates, the respiratory process has traditionally been considered as a catabolic process and the respiratory pathway as a catabolic pathway.

35. What would happen if organisms need to synthesise fatty acids which had already broken down into acetyl CoA?

a) Acetyl CoA would be withdrawn from the pathway
b) Acetyl CoA would be further broken down
c) Ethanol would be released
d) Glycerol would be released

Answer: a

Explanation: When fatty acids are to be used as substrates, then they would be broken down to acetyl CoA before entering the respiratory pathway, but when organisms need to synthesise fatty acids, acetyl CoA would be withdrawn from the respiratory pathway for it.

36. What is catabolism?

a) Joining of substances
b) Breaking down processes
c) Continuous processes
d) Discontinuous processes

Answer: b

Explanation: Catabolism refers to the breaking down processes that occur within the living organisms. Catabolic reactions include glycolysis, the tricarboxylic citric acid cycle, breakdown of fatty acids, etc.

37. What is meant by anabolism?

a) Synthesis of some molecules
b) Breaking down of molecules
c) Joining of bonds
d) Shifting of bonds

Answer: a

Explanation: Anabolism refers to the synthesis of some new molecules, for example, the reaction of glycerol with fatty acids to make lipids, photosynthesis, etc.

38. In mitochondria, which of the following is the site for the oxidation-reduction reaction?

a) Inner membrane
b) Outer membrane
c) Matrix
d) Cristae

Answer: d

Explanation: In mitochondria, cristae re the sites for oxidation-reduction reaction. They produce cellular energy in the form of ATP, hence they are called as powerhouse of the cell.

39. What is an amphibolic pathway?

a) Breaking down processes
b) Another name for catabolic processes
c) Both anabolic and catabolic processes
d) Another name for anabolic processes

Answer: c

Explanation: As the respiratory pathway is involved in both anabolism and catabolism, it is better to consider the respiratory pathway is an amphibolic pathway. Therefore, according to new studies, respiration is treated as an amphibolic pathway and not as a catabolic pathway as according to traditional studies.

40. Which of the following are the end products of the complete combustion of glucose?

a) CO2 and starch
b) Fructose and lactose
c) H2O and mannose
d) CO2 and H2O

Answer: d

Explanation: The complete combustion of glucose, which produces CO2 and H2O as end products, yields energy most of which is given out as heat. If this energy is to be useful to the cell, it should be able to utilise it to synthesise other molecules that the cell requires.

41. What is the strategy of the plants to oxidise glucose?

a) Oxidise glucose in several large steps
b) Oxidise glucose in several small steps
c) Reduce glucose in several large steps
d) Reduce glucose in several small steps

Answer: b

Explanation: The strategy that the plant cell uses is to catabolise the glucose molecule in such a way that not all the liberated energy goes out as heat. The key is to oxidise glucose, not in one step but several small steps.

42. During the process of respiration, which of the following is not released?

a) Carbon dioxide
b) Water
c) Oxygen
d) Energy

Answer: c

Explanation: During the process of respiration, oxygen is utilised and carbon-dioxide, water and energy are released as products. The combustion reaction requires oxygen.

43. What was the kind of atmosphere where the first cells on this planet lived?

a) Reducing
b) Oxidising
c) No atmosphere
d) Gold was present

Answer: a

Explanation: The first cells on this planet lived in an atmosphere that lacked oxygen. Even among present-day living organisms, we know of several organisms that are adapted to anaerobic conditions.

44. What is the breakdown of glucose to pyruvic acid known as?

a) Respiration
b) Glycolysis
c) Combustion
d) Hydrolysis

Answer: b

Explanation: In any case, all living organisms retain the enzymatic machinery to partially oxidise glucose without the help of oxygen. This breakdown of glucose to pyruvic acid is called glycolysis.

45. Where does glycolysis take place?

a) Cytoplasm
b) Mitochondrial matrix
c) Plasma membrane
d) Inner mitochondrial membrane

Answer: a

Explanation: Glycolysis occurs in the cytoplasm of the cell and is present in all the living organisms. In anaerobic organisms, it is the only process in respiration.

Respiration In Plants MCQ For NEET

46. Who discovered fermentation?

a) Gay Lussac
b) Louis Pasteur
c) Kepler
d) Ernst Haeckel

Answer: b

Explanation: Fermentation was discovered by Louis Pasteur. It is incomplete oxidation of glucose which is achieved under anaerobic conditions. It takes place in many prokaryotes and unicellular eukaryotes.

47. What are the final products of fermentation?

a) CO2 and H2O
b) CO2 and methanol
c) H2O and ethanol
d) CO2 and ethanol

Answer: d

Explanation: In the process of fermentation, say by yeast, the incomplete oxidation of glucose is achieved under anaerobic conditions by sets of reactions where pyruvic acid is converted to CO2 and ethanol.

48. Which of the following enzymes is not used under anaerobic conditions?

a) Pyruvic decarboxylase
b) Alcohol dehydrogenase
c) Lactate dehydrogenase
d) Pyruvate dehydrogenase

Answer: d

Explanation: The enzymes like pyruvic decarboxylase and alcohol dehydrogenase catalyse the steps of alcoholic fermentation. Lactate dehydrogenase is used for lactic acid fermentation.

49. Where does lactic acid fermentation take place in animal cells?

a) In the whole body
b) Sometimes in the muscles
c) Main respiratory pathway for muscles
d) In eyes

Answer: b

Explanation: In animal cells, lactic acid fermentation takes place in the muscles during the exercise, when oxygen is inadequate for cellular respiration, pyruvic acid is reduced to lactic acid by lactate dehydrogenase.

50. What is the respiratory quotient for organic acids?

a) More than 1
b) Less than zero
c) Zero
d) Less than one but greater than Zero

Answer: a

Explanation: Organic acids have R.Q value more than one. But when proteins are respiratory substrates the ratio would be about 0.9. Pure proteins or fats are never used as respiratory substrates.

51. How much energy is released in lactic acid and alcohol fermentation?

a) Less than 7 per cent
b) More than 7 per cent
c) More than 50 per cent
d) More than 75 per cent

Answer: a

Explanation: In both lactic acid and alcohol fermentation not much energy is released; less than 7 per cent of the energy in glucose is released and not all of it is trapped as high energy bonds of ATP.

52. At what percentage, yeast poison themselves?

a) 4%
b) 7%
c) 13%
d) 45%

Answer: c

Explanation: Yeast poison to death when the concentration of alcohol reaches about 13 per cent. Therefore, the maximum concentration of alcohol in beverages which are naturally fermented is 13 per cent.

53. In how many ways do different cells handle pyruvic acid?

a) One
b) Two
c) Three
d) Four

Answer: c

Explanation: There are three major ways in which different cells handle pyruvic acid produced by glycolysis:
i. Lactic acid fermentation
ii. Alcoholic fermentation
iii. Aerobic Respiration

54. Glycolysis is also called ________

a) EMP pathway
b) FMR pathway
c) LMS pathway
d) OMS pathway

Answer: a

Explanation: As glycolysis was discovered by three scientists named Embden, Meyerhof and, Parnas, so it also came to be known as the EMP pathway with the initial letters of the discoverers.

55. Which is considered as the universal pathway in a biological system?

a) Krebs cycle
b) Electron Transport System
c) Glycolysis
d) Photo Oxidation

Answer: c

Explanation: As glycolysis is the beginning step of respiration that occurs in the cytoplasm and due to which the pyruvate is formed, therefore it is considered as the universal pathway in biological systems.

56. In glycolysis, one molecule of glucose is reduced to_______

a) fructose
b) pyruvate
c) phosphate
d) phosphoglycerate

Answer: b

Explanation: After the interaction of many co-enzymes and cytochromes, the glucose is at last reduced to two molecules of pyruvic acid which is further reduced to different usable forms in the mitochondria through the Krebs cycle.

57. The net gain of ATP in glycolysis is _____ ATP

a) 16
b) 32
c) 4
d) 8

Answer: d

Explanation: In glycolysis, two NADH are formed that are equivalent to six ATP. Along with this, there is also the production of 2 more ATP after the transfer of high energy phosphate into ADP adds to this thus making the total of eight.

58. Name the protein that helps pyruvate enter into the mitochondrial matrix.

a) Transport protein
b) Contractile protein
c) Adipose protein
d) Secretory protein

Answer: a

Explanation: Pyruvate has to be transported or channeled from the cytoplasm to the mitochondrial matrix. So, transport proteins or channel proteins serve as a means of transport of these molecules across the cellular constituents for further needs.

59. The enzyme that serves as the connecting link between glycolysis and Krebs cycle is ______

a) phosphoenolpyruvic acid
b) glyceraldehyde
c) acetyl CoA
d) isomerase

Answer: c

Explanation: Acetyl CoA or activated acetate is formed as a result of the combination of pyruvate with Sulphur containing coenzyme A. This step is also called gateway step or link reaction as it connects the two main processes of respiration namely glycolysis and Krebs cycle.

60. During glycolysis, one NADH is equivalent to _______ number of ATP.

a) 4
b) 3
c) 2
d) 1

Answer: b

Explanation: In glycolysis, two molecules of NADH are formed at the time of oxidation of glyceraldehyde 3-phosphate to 1, 3-diphosphoglycerate which give rise to 6 ATP. This is converted into respective ATP forms during Electron Transport System.

NEET Questions On Respiration In Plants

61. The scientists that discovered glycolysis are ______

a) Embden, Meyerhof, and Parnas
b) Hans Kreb and John Dalton
c) Rudolf Virchow and Robert Brown
d) Robert Hooke only

Answer: a

Explanation: Glycolysis was discovered by three scientists namely Gustav Embden, Otto Meyerhof and, Jakub Karol Parnas. It can be of many types like homofermentative and heterofermentative pathways.

62. Where does the energy required to carry life processes come from?

a) Food
b) House
c) Earth
d) Galaxy

Answer: a

Explanation: All the energy required for life processes is obtained by the oxidation of some macromolecules that we call as food. All living organisms need energy to carry out daily life activities.

63. Which of the following can synthesise their food?

a) Yellow plants
b) Green plants
c) Animals
d) Mycoplasma

Answer: b

Explanation: Only green plants and cyanobacteria can prepare their food, by the process of photosynthesis. They trap light energy and convert it into chemical energy that is stored in the bonds of carbohydrates.

64. What kind of organisms are fungi?

a) Saprophytes
b) Carnivores
c) Omnivores
d) Herbivores

Answer: a

Explanation: Fungi are generally saprophytes which are dependent on dead and decaying matter. Animals are heterotrophic, i.e., they obtain food from plants directly (herbivores) or indirectly (carnivores).

65. What is meant by cellular respiration?

a) Breakdown of water
b) Breakdown of air to consume energy
c) Breakdown of food materials to release energy
d) Breakdown of soil to release energy

Answer: c

Explanation: Cellular respiration is the mechanism of breakdown of food materials within the cell to release energy and the trapping of this energy for the synthesis of ATP.

66. Where does the photosynthesis take place in eukaryotes?

a) Mitochondria
b) Cytoplasm
c) Chloroplasts
d) Vacuoles

Answer: c

Explanation: Photosynthesis takes place within the chloroplasts in the eukaryotes whereas the breakdown of complex molecules to yield energy takes place in the cytoplasm and the mitochondria.

67. The breaking of which of the following bonds leads to release of energy?

a) P-P bonds
b) C-C bonds
c) N-N bonds
d) S-S bonds

Answer: b

Explanation: The breaking of the C-C bonds of complex compounds through oxidation within the cells, leads to the release of a considerable amount of energy. This process is known as respiration.

68. Which of the following compounds are not oxidised to release energy?

a) Proteins
b) Fats
c) Carbohydrates
d) DNA

Answer: d

Explanation: Nucleic acids like DNA and RNA are never oxidised to release energy because these are integrated parts of the cell and they are used to carry or express different genes in the human beings which carry out different functions like the formation of proteins, fats and carbohydrates.

69. Which of the following acts as the energy currency of the cell?

a) ATP
b) Enzymes
c) Proteins
d) DNA

Answer: a

Explanation: ATP or Adenosine Triphosphate acts as the energy currency of the cell. The energy which is released by the oxidation of respiratory substrates is stored in ATP so that we can use it for future purposes.

70. Which of the following is used as a precursor for the biosynthesis of other molecules?

a) Phosphorous substrate
b) Nitrogen substrates
c) Carbon skeletons
d) Sulphur skeletons

Answer: c

Explanation: Carbon skeletons are used as precursors for the biosynthesis of other biomolecules as the oxidation of these carbon skeletons leads to the formation of ATP which is stored by the cells to be utilised in various-energy requiring processes of the organisms.

71. Which of the following gases do plants require for respiration?

a) O2
b) CO2
c) N2
d) H2O

Answer: a

Explanation: Plants do not require CO2, N2 or water vapour for respiration. Like human beings, plants also require oxygen for respiration so that they can release CO2. It is through photosynthesis, that they require carbon dioxide and release oxygen in a very large amount.

72. By the use of which of the following structures, plants exchange gases?

a) Stem
b) Root
c) Bark
d) Stomata

Answer: d

Explanation: Plants, unlike animals, have no specialised organs for gaseous exchange but they use stomata and lenticels for this purpose. Plants can easily get along without any specialised respiratory organs.

73. Why plants can get along without the need for specialised respiratory organs?

a) It would be an extra expense
b) They don’t like it
c) Each plant part takes care of its own needs
d) Oxygen is easily available for all the parts of the plants

Answer: c

Explanation: There are several reasons why plants can get along without respiratory organs.
i. Each plant part takes care of its own gas-exchange needs
ii. Plants do not present great demands for gas exchange
iii. The distance that gases must diffuse is not large.

74. What are lenticels?

a) Openings on the surface of the bark
b) Openings on the surface of roots
c) Pores on leaves
d) Pores on stem

Answer: a

Explanation: In stems, the living cells are organised in thin layers inside and beneath the bark. They also have openings called lenticels. The cells in the interior are dead and only provide mechanical support.

75. Is it possible to make calculations of the net gain of ATP?

a) Not possible
b) Possible only theoretically
c) Possible only in reality
d) Sometimes possible and sometimes not

Answer: b

Explanation: Yes, it is possible to make calculations of the net gain of the ATP that is formed in the respiratory pathway by the oxidation of some suitable respiratory substrates but this can remain only a theoretical exercise as the real amount of energy released in the cell may vary.

Respiration In Plants Class 11 NEET Questions

76. Which of the following is an assumption of the respiratory balance sheet?

a) Respiration is a sequential pathway
b) Respiration does not exist
c) Energy cannot be calculated in a respiratory pathway
d) Energy is always lost in the form of heat in respiration

Answer: a

Explanation: One of the assumptions made in the respiratory balance sheet is that there is a sequential, orderly pathway functioning, with one substrate forming the next and with glycolysis, TCA cycle and ETS pathway following one after another.

77. Which of the following is not an assumption of the respiratory balance sheet?

a) NADH synthesised in glycolysis is transferred into mitochondria
b) None of the intermediates is used to synthesise other compounds
c) Respiration is a sequential pathway
d) Energy can never be stored

Answer: d

Explanation: Certain assumptions of the respiratory balance sheet include that none of the intermediates in the pathway are utilised to synthesise any other compound. Respiration is a sequential pathway and NADH synthesised in glycolysis is transferred into the mitochondria and undergoes oxidative phosphorylation.

78. Do all the respiratory pathways work simultaneously?

a) No, not at all
b) They take place one after the other
c) Yes, they work simultaneously
d) Sometimes they work independently

Answer: c

Explanation: The assumptions made in the respiratory balance sheet are not valid for the living system. All pathways work simultaneously and do not take place one after another.

79. When is the ATP utilised?

a) It is utilised as and when needed
b) It is never utilised
c) It is only in the stored form
d) Only when the cell is about to replicate

Answer: a

Explanation: ATP is utilised as and when needed. Substrates enter the pathway and are withdrawn from it as and when necessary. Enzymatic rates in these pathways are controlled by multiple means.

80. How many ATP molecules are gained during aerobic respiration?

a) 2 ATP
b) 10 ATP
c) 35 ATP
d) 38 ATP

Answer: d

Explanation: Aerobic respiration involves the complete oxidation of glucose. There can be a net gain of 38 ATP molecules during aerobic respiration of one molecule of glucose.

81. How many ATP molecules are gained during fermentation?

a) 8 ATP
b) 2 ATP
c) 10 ATP
d) 4 ATP

Answer: b

Explanation: In fermentation, there is a net gain of only two molecules of ATP for each molecule of glucose degraded to pyruvic acid whereas many more molecules of ATP are generated under aerobic conditions.

82. What is the speed of oxidation of NADH in case of fermentation?

a) Vigorous
b) Very slow
c) Slow
d) Fast

Answer: c

Explanation: NADH is oxidised to NAD+ rather slowly in fermentation, however, the reaction is very vigorous in the case of aerobic respiration. The reducing agent in fermentation is NADH + H+.

83. What is the full form of RQ?

a) Respiratory Quotient
b) Reservatory Quotient
c) Reservation Q-value
d) Reservatory Q-value

Answer: a

Explanation: RQ stands for Respiratory Quotient. It is the ratio of the volume of CO2 evolved to the volume of O2 consumed in respiration. It is also known as the respiratory ratio.

84. On which of the following does the respiratory quotient depend?

a) The respiratory concentration of Oxygen
b) The respiratory substrate used during respiration
c) The volume of Carbon-dioxide evolved
d) Energy evolved during respiration

Answer: b

Explanation: The respiratory quotient depends upon the type of respiratory substrate used during respiration. In living organisms, respiratory substrates are often more than one.

85. What is the value of RQ in carbohydrates?

a) 0.7
b) 0.3
c) 1
d) 10

Answer: c

Explanation: When carbohydrates are used as substrates and are completely oxidised, the RQ will be 1, because equal amounts of CO2 and O2 are evolved and consumed respectively.

86. What is the RQ value for tripalmitin?

a) 0.9
b) 1
c) 0.3
d) 0.7

Answer: d

Explanation: When fats are used in respiration, the RQ is less than 1. For a fatty acid, tripalmitin, the ratio of the volume of carbon dioxide evolved to the volume of oxygen evolved is 0.7.

Respiration In Plants MCQ For NEET PDF

FAQ and Answers

What would happen if plants does not breath?

If plants does not breath it will not survive. Air is needed for the roots primarily to allow the plants to breathe. When this happens, roots cannot absorb sufficient water and nutrients to the plant, causing yellow or brown leaves, plant stress and a reduced life span of the plant. Roots are denied sufficient air when the soil does not allow for air.

Do pepper plants use special roots for respiration?

Pepper plants use soil respiration. Soil respiration is an important component of the carbon cycle and is also recognized as one of the primary pathways that release CO2 from the soil into the atmosphere in terrestrial ecosystems.

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