9th – Biology – Chapter 8 – BIOENERGETICS

MCQS

1. How much energy is released when ATP is broken down?
   a) 3.5 kcal/mole b) 7.3 kcal/mole c) 10 kcal/mole d) 20 kcal/mole
2. Which kind of respiration needs oxygen?
   a) Anaerobic b) Both c) None d) Aerobic
3. Which two high-energy molecules are formed in the light reaction?
   a) ATP and NADPH b) ATP and CO₂ c) NADH and FADH₂ d) Glucose and O₂
4. Why was anaerobic respiration significant on early Earth?
   a) It produced oxygen for the atmosphere b) It allowed early organisms to get energy without free oxygen c) It synthesized glucose d) It occurred in chloroplasts
5. Bioenergetics is the study of what?
   a) How organisms reproduce b) How living organisms acquire, convert, store, and utilize energy c) How organisms move d) How organisms digest food
6. Fermentation is used in the preparation of which of the following?
   a) Yogurt b) Cheese c) Bread d) All of the above
7. In which part of the cell do the light reactions of photosynthesis take place?
   a) Plasma membrane of cell b) Cytoplasm of cell c) Stroma of chloroplasts d) Thylakoids of chloroplasts
8. What is the net gain of ATP molecules in anaerobic respiration?
   a) 36 b) 2 c) 4 d) 10
9. Which kind of respiration yields the greatest amount of energy?
   a) Aerobic b) Anaerobic c) Photosynthesis d) Fermentation
10. At which site do the light reactions of photosynthesis occur?
    a) In the stroma of chloroplasts b) In the cytoplasm c) In the mitochondria d) On the thylakoid membranes of chloroplasts
11. Which three components make up an ATP molecule?
    a) Adenine, ribose, and two phosphate groups b) Adenine, glucose, and three phosphate groups c) Adenine, ribose, and three phosphate groups d) Adenosine, ribose, and one phosphate group
12. What is the net ATP gain from one glucose molecule in anaerobic respiration?
    a) 2 b) 4 c) 12 d) 36
13. According to the comparison table, where does photosynthesis take place?
    a) In all cells b) In chloroplasts in green parts only c) In mitochondria d) In the cytoplasm
14. Which of the following is obtained through fermentation?
    a) Glucose b) Oxygen c) Water d) Cheese
15. Which wavelengths of light do chlorophylls absorb most strongly?
    a) Green and blue b) Red and blue c) Green and red d) Only green
16. How do aerobic and anaerobic respiration differ in the amount of energy they release?
    a) Anaerobic releases more energy b) Aerobic releases more energy c) Both release the same amount of energy d) Aerobic releases no energy
17. Which high-energy molecules are formed in the light reactions of photosynthesis?
    a) Glucose and O₂ b) ATP and NADPH c) CO₂ and H₂O d) ADP and Pi
18. What is the end product of the Calvin Cycle (dark reactions)?
    a) ATP b) Oxygen c) NADPH d) Glucose
19. What occurs in lactic acid fermentation?
    a) Pyruvic acid is converted to ethanol b) Pyruvic acid is converted to lactic acid c) Glucose is fully oxidized d) Oxygen is produced
20. What part do oxidation-reduction (redox) reactions play in bioenergetics?
    a) They synthesize glucose b) They transfer electrons to generate energy in the form of ATP c) They break down chlorophyll d) They store oxygen in cells
21. According to the comparison table, when does respiration take place?
    a) Only in daytime b) Only at night c) All the time d) In the presence of light
22. Between which components are the high-energy bonds of ATP located?
    a) Adenine and Ribose b) Ribose and Phosphate c) Two phosphate groups d) Oxygen and Hydrogen
23. What is the main purpose of photosynthesis?
    a) To break down glucose b) To synthesize glucose from carbon dioxide and water using sunlight c) To produce ATP directly d) To release carbon dioxide
24. Where do the dark reactions of photosynthesis occur?
    a) Thylakoid membranes b) Stroma c) Mitochondria d) Cytoplasm
25. Which food molecule do cells use most commonly to obtain energy?
    a) Proteins b) Glucose c) Lipids d) Nucleic acids
26. How is cellular respiration defined?
    a) The synthesis of glucose b) The oxidation of food inside cells to release energy c) The absorption of sunlight d) The breakdown of ATP into ADP
27. Which molecule serves as the principal energy currency in all cells?
    a) Glucose b) ADP c) ATP d) NADPH
28. In which organelle does cellular respiration mainly take place?
    a) Chloroplast b) Nucleus c) Golgi apparatus d) Mitochondria
29. What is the name given to the study of how living organisms acquire, convert, store, and utilize energy?
    a) Biochemistry b) Bioenergetics c) Physiology d) Genetics
30. According to the table comparing photosynthesis and respiration, which process is anabolic?
    a) Respiration b) Photosynthesis c) Fermentation d) Glycolysis
31. In which location does the Krebs Cycle take place?
    a) Cytoplasm b) Chloroplast c) Mitochondrial matrix d) Ribosome
32. In the ATP-ADP cycle, which components combine to form ATP?
    a) ADP and glucose b) AMP and oxygen c) NADPH and water d) ADP and inorganic phosphate (Pi)
33. What becomes of pyruvic acid before it enters the Krebs Cycle?
    a) It is converted into glucose b) It is broken into ethanol c) It is stored in the cytoplasm d) It is converted into acetyl coenzyme A, CO₂, and NADH
34. What are the products when yeast ferments glucose?
    a) Alcohol and CO₂ b) Alcohol and water c) Lactic acid d) CO₂ and H₂O
35. What is the full form of ATP?
    a) Adenine Triphosphate b) Adenosine Triphosphate c) Adenosine Tetraphosphate d) Adenine Tripolymer
36. What percentage of the light striking a leaf surface is absorbed by pigments?
    a) 10% b) 5% c) 1% d) 50%
37. Which molecule is the main energy currency of all cells?
    a) DNA b) RNA c) ATP d) Glucose
38. What does anaerobic respiration in yeast produce?
    a) Lactic acid b) Ethanol and CO₂ c) ATP and H₂O d) Glucose
39. How much energy is liberated when a single phosphate bond in ATP is broken?
    a) 7.3 kcal/mole b) 3.7 kcal/mole c) 10 kcal/mole d) 5 kcal/mole
40. Which molecule is formed when ADP is broken down further?
    a) ATP b) Glucose c) NADH d) AMP
41. What is the name of the process in which food is broken down to release energy?
    a) Photosynthesis b) Cellular Respiration c) Fermentation d) Digestion
42. Which pigment is the principal one involved in photosynthesis?
    a) Carotenoids b) Chlorophyll a c) Chlorophyll b d) Xanthophyll
43. Which pigment is the chief light-absorbing pigment of photosynthesis?
    a) Chlorophyll b b) Carotenoids c) Chlorophyll a d) Hemoglobin
44. Which bonds are broken to release energy from ATP?
    a) P–P bonds b) C–H bonds c) C–N bonds d) C–O bonds
45. Which energy-rich compounds are formed in the Krebs Cycle?
    a) ATP and NADPH b) ADP and Pi c) CO₂ and H₂O d) NADH and FADH₂
46. For which of the following is ATP used?
    a) Muscle contraction b) Photosynthesis c) Storing glucose d) DNA replication
47. What is the initial step of cellular respiration called?
    a) Krebs Cycle b) Glycolysis c) Electron Transport Chain d) Calvin Cycle
48. Who worked out the details of the dark reactions (Calvin Cycle)?
    a) Sir Hans Krebs b) Melvin Calvin c) Albert Einstein d) Robert Hooke
49. What is the last step of aerobic respiration?
    a) Glycolysis b) Krebs Cycle c) Electron Transport Chain d) Photosynthesis
50. What does glycolysis yield from one glucose molecule?
    a) 2 pyruvic acid, 2 ATP, and 2 NADH b) 2 ATP and 2 NADPH c) 4 ATP and 2 CO₂ d) 2 lactic acid and 2 ATP
51. In which organelle does photosynthesis take place?
    a) Mitochondria b) Chloroplasts c) Nucleus d) Ribosomes
52. Under what condition does anaerobic respiration take place?
    a) Presence of oxygen b) Absence of oxygen c) Mitochondria d) Chloroplast
53. For what is the energy released by respiration used?
    a) DNA replication b) Active transport c) Maintenance of body temperature d) All of the above
54. What becomes of water molecules in the light reactions?
    a) They are converted into glucose b) They combine with carbon dioxide c) They are stored in the stroma d) They are broken down, releasing oxygen and hydrogen ions
55. In which of the following does lactic acid fermentation take place?
    a) Yeast b) Bacteria c) Human muscles d) Plants
56. What function do NADH and FADH₂ serve in cellular respiration?
    a) Breaking glucose b) Storing oxygen c) Carrying electrons d) Producing CO₂
57. What takes place when ATP is converted into ADP?
    a) Energy is stored b) One phosphate group is released along with energy c) Glucose is produced d) Oxygen is consumed
58. At which site does glycolysis take place?
    a) Mitochondria b) Chloroplasts c) Cytoplasm d) Nucleus
59. Which equation represents alcoholic fermentation?
    a) 2(C₃H₄O₃) → 2(C₂H₅OH) + 2CO₂ b) C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O c) 2(C₃H₄O₃) + 4H → 2(C₃H₆O₃) d) 6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂
60. Which form of chlorophyll occurs most commonly in plants?
    a) Chlorophyll a b) Chlorophyll b c) Chlorophyll c d) Chlorophyll d
61. What is the net gain of ATP molecules from the aerobic respiration of one glucose molecule?
    a) 2 b) 36 c) 4 d) 10
62. In which part of the chloroplast do the dark reactions occur?
    a) Stroma of chloroplast b) Thylakoids of chloroplast c) Outer membrane d) Cytoplasm
63. What do muscles produce when oxygen runs low during exercise?
    a) Carbon dioxide b) Glucose c) Lactic acid d) Ethanol
64. Who discovered the dark reactions?
    a) Melvin Calvin b) Hans Krebs c) Gregor Mendel d) Robert Hooke
65. Which are the two principal types of respiration?
    a) Active and Passive b) Cellular and Mitochondrial c) Oxidative and Reductive d) Aerobic and Anaerobic
66. Into what is glucose converted during glycolysis?
    a) ATP b) Pyruvic acid c) Lactic acid d) NADH
67. At which site does the Krebs Cycle occur?
    a) Cytoplasm b) Thylakoid membranes c) Matrix of mitochondria d) Stroma of chloroplasts
68. In which part of the cell is ATP mainly stored?
    a) Mitochondria b) Ribosome c) Nucleus d) Golgi apparatus
69. Which is the general equation of photosynthesis?
    a) C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O b) 6CO₂ + 12H₂O + light → C₆H₁₂O₆ + 6O₂ + 6H₂O c) 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂ d) 12CO₂ + 6H₂O → C₆H₁₂O₆ + 12O₂
70. What is the feature that sets aerobic respiration apart from anaerobic respiration?
    a) Presence of oxygen b) Production of glucose c) Location in the cell d) Use of chlorophyll
71. Which of these is not a use of respiratory energy (ATP) in the body?
    a) Muscle contractions b) Synthesis of biomolecules c) Photosynthesis d) Transmission of nerve impulses
72. Which molecule gives up electrons in the light-dependent reactions of photosynthesis?
    a) NADPH b) Water c) Oxygen d) Carbon dioxide
73. What function does the electron transport chain serve in photosynthesis?
    a) It breaks down glucose b) It synthesizes chlorophyll c) It releases carbon dioxide d) It transfers high-energy electrons to produce ATP
74. How do plants mainly get their energy?
    a) By consuming food b) Through respiration c) By capturing sunlight through photosynthesis d) By breaking down ATP
75. Which of the following gives the general equation of photosynthesis?
    a) CO₂ + H₂O → C₆H₁₂O₆ + O₂ b) C₆H₁₂O₆ + O₂ → CO₂ + H₂O c) ATP + O₂ → CO₂ + H₂O d) CO₂ + H₂O → ATP + O₂
76. Which process makes use of respiratory energy to maintain body temperature?
    a) Glycolysis b) Cellular respiration c) Photosynthesis d) Fermentation
77. Which stage of aerobic respiration generates the largest amount of ATP?
    a) Glycolysis b) Krebs cycle c) Electron transport chain d) Fermentation
78. Which byproduct is commonly formed in anaerobic respiration in animal cells?
    a) Oxygen b) Water c) Lactic acid d) Carbon dioxide
79. What does chlorophyll do in photosynthesis?
    a) It transports glucose b) It breaks down water molecules c) It produces oxygen directly d) It absorbs sunlight and converts it into chemical energy
80. Which are the end products of aerobic respiration?
    a) Lactic acid and CO₂ b) Ethanol and CO₂ c) CO₂ and H₂O d) Glucose and O₂
81. Why is fermentation valuable for certain organisms?
    a) It produces more ATP than aerobic respiration b) It synthesizes glucose c) It occurs in chloroplasts d) It allows energy production in the absence of oxygen
82. Which wavelengths of light does chlorophyll-a mainly absorb?
    a) Green and yellow b) Blue and red c) Red and green d) Blue and yellow
83. According to the table, in which location does anaerobic respiration take place?
    a) Mitochondria b) Cytoplasm c) Chloroplasts d) Nucleus
84. What is the first phase of photosynthesis called?
    a) Dark Reaction b) Krebs Cycle c) Light Reaction d) Glycolysis
85. How many phosphate groups are present in an ATP molecule?
    a) 1 b) 2 c) 3 d) 4

Short Questions

1. Why is photosynthesis considered the most important metabolic reaction?
2. Why is ATP called the “energy currency” of the cell?
3. State the equation (in words or symbols) for aerobic respiration.
4. What causes muscle fatigue?
5. What are the end products of anaerobic respiration in animals and yeast?
6. Why do plants store energy in carbohydrates instead of ATP?
7. What happens to water molecules during light reactions?
8. Where does glycolysis occur?
9. What are the two types of respiration?
10. What is anaerobic respiration?
11. Where does the electron transport chain occur?
12. Where do the light reactions of photosynthesis take place?
13. What do ATP and ADP mean? What are the roles of these molecules for cellular metabolism?
14. What is bioenergetics?
15. What is cellular respiration?
16. How does chlorophyll contribute to the color of plants?
17. How does chlorophyll absorb light energy?
18. What is NADP and what is its function in photosynthesis?
19. How does alcoholic fermentation occur?
20. Name some useful products obtained through fermentation.
21. Why is ATP required for muscle contraction?
22. List ways in which respiratory energy is used in the body.
23. What are the waste products of cellular respiration?
24. Write a brief note on the role of oxygen in aerobic respiration.
25. Why is oxygen important in aerobic respiration?
26. What is the product of glycolysis?
27. What was Melvin Calvin’s contribution to biology?
28. What are the main uses of ATP in the body?
29. What is photosynthesis?
30. Where do the dark reactions occur?
31. Why do plants need both photosynthesis and respiration?
32. How is lactic acid fermentation different from alcoholic fermentation?
33. What is ATP and what does it stand for?
34. What is the role of the Krebs Cycle?
35. How do plants and animals obtain energy differently?
36. What is the role of chlorophyll in photosynthesis?
37. What are the products of the light reaction?
38. Why did early organisms rely on anaerobic respiration?
39. What is the role of ATP in cellular energy transfer?
40. Why are redox reactions important in metabolism?
41. How does ATP help maintain body temperature?
42. Write the equation for alcoholic fermentation.
43. How does ATP help in active transport?
44. What are the three main steps of aerobic respiration?
45. Which organisms carry out photosynthesis? Which cell organelle is responsible for the absorption of light for photosynthesis?
46. What are NADH and FADH₂?
47. How does fermentation help in food production?
48. Write the chemical equation for photosynthesis.
49. What happens to glucose during respiration?
50. Why is chlorophyll important for photosynthesis?
51. What happens to ADP if further energy is needed?
52. How is oxygen produced during photosynthesis?
53. Why is aerobic respiration more efficient than anaerobic respiration?
54. What are the two main phases of photosynthesis?
55. How is ATP used in nerve transmission?
56. How does the energy flow from the sun reach animals?
57. Name the three subunits of ATP.
58. Write the chemical equation for cellular respiration.
59. How does fermentation benefit organisms living in oxygen-poor environments?
60. How do organisms get energy from food?
61. What are the reactants and products of photosynthesis?
62. What are autotrophic organisms?
63. What is the ATP-ADP cycle?
64. Why do muscles undergo anaerobic respiration during intense exercise?
65. What is the significance of accessory pigments?
66. Why is ATP needed for detoxification processes?
67. Write the importance of oxidation-reduction reactions.
68. Why is ATP considered a renewable source of energy?
69. How does the structure of ATP enable it to store and release energy efficiently?
70. What happens when ATP is broken down?
71. Where does lactic acid fermentation occur in the human body?
72. Write down the word equation for photosynthesis.
73. What is the Calvin Cycle?
74. Why do different pigments absorb different wavelengths of light?
75. What is fermentation?
76. How much energy is released when one phosphate bond of ATP breaks?
77. Why do mitochondria have a folded inner membrane?
78. What is the primary molecule for energy storage in cells?
79. How does aerobic respiration differ from anaerobic respiration?
80. What role does ATP play in DNA replication?
81. How do living organisms obtain energy?
82. Define anaerobic and aerobic respiration.
83. How does carbon dioxide contribute to dark reactions?
84. Why do different organisms have different metabolic rates?
85. How is ATP formed in the body?
86. Define oxidation and reduction in biological systems.
87. State the main purpose of cellular respiration.
88. What was Fritz Lipmann’s contribution to bioenergetics?
89. How do muscles respond to oxygen deficiency during intense exercise?
90. How does the electron transport chain produce ATP?

Long Questions

1. Describe the structure and function of ATP. Explain the ATP-ADP cycle.
2. What is bioenergetics? Explain the role of ATP in energy transfer.
3. What is the role of chlorophyll in photosynthesis? How do pigments absorb light energy?
4. Compare aerobic and anaerobic respiration in terms of energy production and efficiency.
5. Write a note on the intake of carbon dioxide and water by plants.
6. What is fermentation? Describe its types and significance.
7. Explain the importance of ATP in cellular activities and energy utilization.
8. Outline the processes involved in photosynthesis.
9. Explain the mechanism of cellular respiration, covering glycolysis, the Krebs Cycle, and the electron transport chain.
10. Compare respiration and photosynthesis, highlighting their differences and relationships.
11. Compare the processes of respiration and photosynthesis.
12. Explain ATP as a molecule that is the chief energy currency of all cells.
13. Outline the mechanism of aerobic respiration.
14. How does the human body utilize ATP for various functions?
15. Explain the process of photosynthesis, including its light and dark reactions.
16. Explain the types and importance of anaerobic respiration.

Answer Key

1. b) 7.3 kcal/mole
2. d) Aerobic
3. a) ATP and NADPH
4. b) It allowed early organisms to get energy without free oxygen
5. b) How living organisms acquire, convert, store, and utilize energy
6. d) All of the above
7. d) Thylakoids of chloroplasts
8. b) 2
9. a) Aerobic
10. d) On the thylakoid membranes of chloroplasts
11. c) Adenine, ribose, and three phosphate groups
12. a) 2
13. b) In chloroplasts in green parts only
14. d) Cheese
15. b) Red and blue
16. b) Aerobic releases more energy
17. b) ATP and NADPH
18. d) Glucose
19. b) Pyruvic acid is converted to lactic acid
20. b) They transfer electrons to generate energy in the form of ATP
21. c) All the time
22. c) Two phosphate groups
23. b) To synthesize glucose from carbon dioxide and water using sunlight
24. b) Stroma
25. b) Glucose
26. b) The oxidation of food inside cells to release energy
27. c) ATP
28. d) Mitochondria
29. b) Bioenergetics
30. b) Photosynthesis
31. c) Mitochondrial matrix
32. d) ADP and inorganic phosphate (Pi)
33. d) It is converted into acetyl coenzyme A, CO₂, and NADH
34. a) Alcohol and CO₂
35. b) Adenosine Triphosphate
36. c) 1%
37. c) ATP
38. b) Ethanol and CO₂
39. a) 7.3 kcal/mole
40. d) AMP
41. b) Cellular Respiration
42. b) Chlorophyll a
43. c) Chlorophyll a
44. a) P–P bonds
45. d) NADH and FADH₂
46. a) Muscle contraction
47. b) Glycolysis
48. b) Melvin Calvin
49. c) Electron Transport Chain
50. a) 2 pyruvic acid, 2 ATP, and 2 NADH
51. b) Chloroplasts
52. b) Absence of oxygen
53. d) All of the above
54. d) They are broken down, releasing oxygen and hydrogen ions
55. c) Human muscles
56. c) Carrying electrons
57. b) One phosphate group is released along with energy
58. c) Cytoplasm
59. a) 2(C₃H₄O₃) → 2(C₂H₅OH) + 2CO₂
60. a) Chlorophyll a
61. b) 36
62. a) Stroma of chloroplast
63. c) Lactic acid
64. a) Melvin Calvin
65. d) Aerobic and Anaerobic
66. b) Pyruvic acid
67. c) Matrix of mitochondria
68. a) Mitochondria
69. b) 6CO₂ + 12H₂O + light → C₆H₁₂O₆ + 6O₂ + 6H₂O
70. a) Presence of oxygen
71. c) Photosynthesis
72. b) Water
73. d) It transfers high-energy electrons to produce ATP
74. c) By capturing sunlight through photosynthesis
75. a) CO₂ + H₂O → C₆H₁₂O₆ + O₂
76. b) Cellular respiration
77. c) Electron transport chain
78. c) Lactic acid
79. d) It absorbs sunlight and converts it into chemical energy
80. c) CO₂ and H₂O
81. d) It allows energy production in the absence of oxygen
82. b) Blue and red
83. b) Cytoplasm
84. c) Light Reaction
85. c) 3