Bioenergetics MCQs / Quizzes and SQs

Bioenergetics MCQs / Quizzes and SQs (School)

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MCQs / Quiz

1. In which of the following steps of respiration is CO₂ produced?

1. Glycolysis
2. Krebs cycle
3. Electron transport chain
4. All of these

2. Oxygen takes part in aerobic respiration in:

1. Glycolysis
2. Krebs cycle
3. Electron transport chain
4. Both b & c

3. When a plant was kept in darkness for many days, its leaves turned yellow. Why?

1. Leaves could not get oxygen and so there was no photosynthesis
2. Leaves could not get light and so there was no respiration
3. Leaves could not get oxygen and so there was no respiration
4. Leaves could not get light and so there was no photosynthesis

4. From which bonds of ATP molecules is energy taken?

1. P-P bonds
2. C-H bonds
3. C-N bonds
4. C-O bonds

5. In which component of the leaf cells, is chlorophyll present?

1. Stroma
2. Thylakoids
3. Plasma membrane
4. Cytoplasm

6. Which of these can enter into Krebs cycle?

1. Glucose
2. Pyruvic acid
3. Citric acid
4. Acetyl Co-A

7. When we work hard we suffer, from muscle fatigue because muscle cells:

1. Carry out aerobic respiration at faster rate and so are tired
2. Carry out anaerobic respiration and so accumulate more CO₂
3. Carry out anaerobic respiration and so accumulate lactic acid
4. Carry out aerobic respiration at faster rate and so accumulate lactic acid

8. How many molecules of CO₂ are produced when Krebs cycle operates once?

1. 1
2. 2 ANS
3. 3
4. 6

9. Calvin got Nobel Prize in:

1. 1961
2. 1971
3. 1985
4. 1991

10. Each ATP molecule has the number of sub-units:

1. 3 ANS
2. 4
3. 1
4. 2

11. Redox reactions involve exchange of:

1. Electrons
2. Protons
3. Neutrons
4. Atoms

12. In living organism, redox reactions involve the loss and gain of:

1. Oxygen
2. Carbon
3. Nitrogen
4. Hydrogen

13. The major energy currency of all cells is:

1. ADP
2. ATP
3. AMP
4. P-bonds

14. Number of carbon atoms attached to ribose sugar:

1. Two
2. Three
3. Five
4. Ten

15. Number of P-bonds in an ATP molecule:

1. Two
2. Nine
3. Six
4. Four

16. The breaking of one phosphate bond from ATP releases energy:

1. 7.9 Kcal
2. 7.5 Kcal
3. 7.1 Kcal
4. 7.3 Kcal

17. Muscle fatigue is caused by:

1. Pyruvic acid
2. Lactic acid
3. Alcohol
4. Carbon dioxide

18. ATP is an example of:

1. Amino acid
2. Fatty acid
3. Nucleic acid
4. Nucleotide

19. Dark reactions take place in:

1. Stroma
2. Mitochondria
3. Nucleus
4. Thylakoids

20. The raw materials in photosynthesis are:

1. Water, Oxygen
2. CO₂, O₂
3. Water, CO₂
4. Glucose, Water

21. The water from the soil enters into the root hairs by the process of:

1. Photosynthesis
2. Osmosis
3. Diffusion
4. Respiration

22. The air enters the leaf through:

1. Pits
2. Stomata
3. Mesophyll
4. Xylem vessels

23. The light reactions of photosynthesis take place on the:

1. Stroma
2. Thylakoid membrane
3. Lumen
4. Sacs

24. The reactions which do not require light during photosynthesis are called:

1. Chemical reaction
2. Redox reaction
3. Dark reaction
4. Light reaction

25. Electrons are passed to ETC to produce:

1. AMP
2. ATP
3. ADP
4. GTP

26. The 6-carbon compounds during the dark reactions of photosynthesis split into two __ carbon compounds:

1. 5
2. 3 ANS
3. 7
4. 4

27. How much percentage of the light falling on the leaf surface is absorbed?

1. 1% ANS
2. 2%
3. 3%
4. 4%

28. Site for occurrence of aerobic respiration is:

1. Cytoplasm
2. Mitochondria
3. Cytoplasm and Mitochondria
4. Golgi apparatus

29. Final product of aerobic respiration are:

1. H₂O
2. Lactic acid and CO₂
3. Ethanol and CO₂
4. CO₂ and H₂O

30. In which process of aerobic respiration does oxygen take part?

1. Glycolysis
2. Krebs cycle
3. Mid phase of glycolysis and Krebs cycle
4. Electron transport chain

31. Photosynthesis takes place in:

1. Chloroplasts
2. Cytoplasm
3. Mitochondria
4. Cytosol

32. Final products of anaerobic respiration are:

1. Lactic acid
2. Ethanol
3. CO₂
4. All of these

33. The process of glycolysis occurs in / Process of glycolysis is found in:

1. Mitochondria
2. Cytoplasm
3. Endoplasmic reticulum
4. Nucleus

34. Fungi Aspergillus is used for making:

1. Yogurt
2. Cheese
3. Soya Sauce
4. Baking

35. Pyruvic acid is a __ carbon compound:

1. 5
2. 4
3. 3 ANS
4. 2

36. During anaerobic oxidation of glucose molecule how many molecules of ATP are gained as net profit?

1. 2 ANS
2. 4
3. 6
4. 8

37. Chlorophyllous pigment absorbs maximum light in wavelengths of:

1. Green and blue
2. Green and red
3. Green only
4. Red and blue

38. ATP was discovered by:

1. Schwann
2. J. Purkinji
3. Darwin
4. Karl Lohmann

39. How many ATP molecules are formed during cellular respiration?

1. 40
2. 38
3. 63
4. 36 ANS

40. The covalent bond connecting two phosphates is indicated by:

1. Ratio
2. Proportion
3. Colon
4. Tilde

41. 2 FADH₂ of Krebs cycle produces ATP molecules:

1. 2
2. 6
3. 4 ANS
4. 18

42. In Glycolysis:

1. No ATP produces
2. Oxygen is involved in this step
3. Takes place in the mitochondrion
4. Reduces two molecules of NAD⁺ for every glucose molecule processed

43. The Krebs cycle:

1. Takes place in the mitochondrion
2. Reduces two molecules of NAD⁺ for every glucose molecule processed
3. Is the same thing as fermentation
4. Has no connection with the respiratory chain

44. At much higher light intensity the rate of photosynthesis:

1. Increases
2. Decreases
3. Constant
4. First increases then decreases

45. The quantitative study of energy relationships in the biological system is called:

1. Biochemistry
2. Biotechnology
3. Bioenergetics
4. Biophysics

46. 6 NADH of Krebs cycle produces ATP molecules:

1. 4
2. 6
3. 18 ANS
4. 36

47. ATP discovered by Karl Lohmann in:

1. 1822
2. 1929 ANS
3. 1900
4. 1978

48. Adenine is a:

1. Double ringed nitrogenous base
2. Single ringed nitrogenous base
3. Three ringed nitrogenous base
4. Linear chain of hydrocarbons

49. Each NADH produces how many ATP molecules in Electron transport chain?

1. 2
2. 3 ANS
3. 4
4. 5

50. Each FADH₂ produces ATP molecules:

1. 2 ANS
2. 3
3. 6
4. 32

51. How many molecules are spent to transport NADH of glycolysis across the mitochondrial membrane?

1. 1 ANS
2. 2
3. 3
4. 4

52. Before entering Krebs cycle, pyruvic acid is changed into a 2-carbon compound called:

1. Coenzyme-A
2. Acetyl CoA
3. CO₂
4. Glucose

53. Which of the following is not a limiting factor in photosynthesis?

1. Light intensity
2. Temperature
3. Oxygen
4. Concentration of CO₂

54. ATP is the main source for all except:

1. Synthesis of macromolecules
2. Movement and transmission of nerve impulses
3. Exocytosis and endocytosis
4. Diffusion

55. Energy stored in chemical bonds is:

1. Potential energy
2. Kinetic energy
3. Light energy
4. Heat energy

56. Final step of cellular respiration is:

1. Electron transport chain
2. Krebs cycle
3. Glycolysis
4. Lactic acid fermentation

57. The NADH generated in glycolysis gives:

1. 2 ATP ANS
2. 3 ATP
3. 4 ATP
4. 5 ATP

58. Accessory pigments include:

1. Chlorophyll-a
2. Chlorophyll-b
3. Carotenoids
4. Chlorophyll-b and carotenoids

59. Main photosynthetic pigment:

1. Chlorophyll-a
2. Chlorophyll-b
3. Carotenoids
4. Chlorophyll-b and carotenoids

60. In cellular respiration, food is oxidized to CO₂, while O₂ is reduced into:

1. C₂H₁₂O₆
2. H₂O
3. C₃H₄O₃
4. C₂H₆O₃

61. When life evolved on the earth, early organisms respired:

1. Aerobically
2. Anaerobically
3. Anaerobically and aerobically
4. By diffusion

62. A double ringed nitrogenous base is:

1. Cytosine
2. Uracil
3. Adenine
4. Thymine

63. In lactic acid fermentation, pyruvic acid is converted into:

1. C₂H₅OH
2. C₃H₆O₃
3. CO₂
4. C₂H₅OH and CO₂

64. Fermentation in yeasts is used in:

1. Brewing
2. Baking
3. Making cheese
4. Brewing and Baking

65. Pigments are the substances that absorb:

1. Invisible light
2. Visible light
3. Invisible and visible light
4. Vapors

66. The most common fuel used by cell to get energy by cellular respiration is:

1. Starch
2. Lipids
3. Glucose
4. Proteins

67. The cellular respiration occurring in the present of oxygen is called:

1. Redox reaction
2. Anaerobic respiration
3. Aerobic respiration
4. Oxidation Reduction reaction

68. The cellular respiration occurring in the absence of oxygen is called:

1. Anaerobic respiration
2. Oxidation Reduction reaction
3. Aerobic respiration
4. Redox reaction

69. A glucose is a molecule of:

1. 3-C
2. 6-C ANS
3. 5-C
4. 4-C

70. The example of 3-C molecule is:

1. Glucose
2. Ribose
3. Pyruvic acid
4. Starch

71. Alcoholic fermentation occurs in:

1. Bacteria
2. Yeast
3. Man
4. Bacteria and yeast

72. Lactic fermentation occurs in:

1. Protozoans
2. Skeletal muscles of humans
3. Aerobes
4. Yeasts

73. The organisms which get energy from anaerobic respiration are called:

1. Aerobes
2. Anaerobes
3. Aerobes and anaerobes
4. Protozoans

74. In alcoholic fermentation, pyruvic acid is broken down into:

1. C₂H₅OH
2. CO₂
3. C₂H₆O₃
4. C₂H₅OH and CO₂

Short Questions

Q1. What is acetyl Co-A?

Ans. Before entering Krebs cycle, pyruvic acid combines with coenzyme A and changed into a 2-carbon compound called acetyl Co-A.

Q2. Describe the structure of adenine.

Ans. It is a double-ringed nitrogenous base used in the molecular structure of ATP.

Q3. What is ADP? Ans. ADP stands for Adenosine Diphosphate. When terminal bond of ATP is broken, a large amount of energy is released and ATP is converted into ADP. The breaking of one phosphate bond releases about 7300 calories per mole of energy.

Adenosine - PO₄ - PO₄ - PO₄ = ATP

Adenosine - PO₄ - PO₄ --> ADP + P_i + 7.3 K cal/mole

Q4. Define aerobic respiration.

Ans. A type of respiration in which complete oxidation of glucose occur with maximum release of energy in presences of oxygen.

C₆H₁₂O₆ + 6O₂ --> 6CO₂ + H₂O + Energy

Q5. What is Alcoholic fermentation?

Ans. In this type of fermentation, pyruvic acid is further broken down into alcohol (C₂H₅OH) and carbon dioxide (CO₂). 

Example: Pyruvic Acid --> Ethyl alcohol + Carbon dioxide 2ATP molecules of energy are produced. It occurs in bacteria and yeast.

Q6. What is AMP? Ans. AMP stands for adenosine monophosphate. ADP is broken to AMP and P_i is released.

ADP + H₂O --> AMP + P_i + energy (7.3 Kcal/mole)

Q7. Define anaerobic respiration (fermentation).

Ans. Some organisms oxidize their food incompletely without using any molecular oxygen called anaerobic respiration. Glucose is incompletely oxidized with less amount of energy released. It is of two types:

i: Lactic acid fermentation ii: Alcoholic fermentation

Q8. What is ATP?

Ans. ATP is abbreviation of adenosine tri-phosphate. It contains adenosine and three phosphates.

Adenosine - PO₄ - PO₄ - PO₄

ATP is energy currency. It is a packet of energy produced in mitochondria by oxidation of glucose.

Q9. What is the difference between aerobic and anaerobic respiration?

Ans. Aerobic Respiration: It takes place in presence of oxygen. 36 ATP are produced as net profit in this type. It occurs in cytoplasm and mitochondria.

Anaerobic Respiration: It takes place in absence of oxygen. 2 ATP are produced as net profit in this type. It occurs in cytoplasm.

Q10. Define bioenergetics.

Ans. Bioenergetics is the study of energy relationships and energy transformations (conversions) in living organisms.

Q11. What is Calvin cycle?

Ans. Calvin cycle is also called dark reaction. Dark reaction is second phase of photosynthesis. It does not require light energy. In this reaction, glucose is synthesized in the absence of sunlight but energy required is obtained NADPH and ATP formed during light reaction. He was awarded Nobel prize in 1961 for this.

Q12. What is Chlorophyll?

Ans. Chlorophyll is a green pigment inside the chloroplasts of plant cells. Sunlight is absorbed by chlorophyll. It is then converted into chemical energy which drives photosynthetic process.

Q13. Define Coenzyme-A.

Ans. The enzyme which combines with pyruvic acid to form acetyl Co-A before entering Krebs cycle is called coenzyme A.

Q14. Define Electron Transport Chain (ETC).

Ans. The final phase of cellular respiration in which the compounds NADH and FADH₂ are oxidized and their electrons pass along a chain of oxidation reduction steps to produce ATP. This chain is called Electron Transport Chain.

Q15. What is FAD?

Ans. Flavin adenine dinucleotide (FAD) is also a coenzyme like NAD⁺. It gets 2 hydrogen and reduces to FADH₂.

Q16. What is glycolysis?

Ans. It is the first stage of aerobic respiration. In glycolysis, glucose is converted into pyruvic acid. It occurs in cytoplasm and oxygen is not involved in this stage.

Q17. What is Krebs cycle?

Ans. It is the second stage of aerobic respiration. In Krebs cycle, the pyruvic acid molecules are completely oxidized into CO₂ and H₂O along with formation of ATP, NADH and FADH₂.

Q18. What is Lactic acid Fermentation?

Ans. It is a type of anaerobic respiration. Each pyruvic acid molecules is converted into lactic acid (C₃H₆O₃).

It occurs in skeletal muscles of humans and other animals during extreme physical activities. This also happens in the bacteria present in milk.

Q19. Define light-dependent reactions, or light reactions.

Ans. During the first phase of photosynthesis, light energy is captured and is used to make high energy molecules i.e. ATP and NADP. It takes place in thylakoid membranes of chloroplast. These reactions take place in the stroma of the chloroplast.

Q20. What are limiting factors?

Ans. Any environment factor, the absence or deficiency of which can decrease the rate of a metabolic reaction is called limiting factor.

Q21. NADPH stands for what?

Ans. NAD (Nicotinamide Adenine Dinucleotide) is a co-enzyme that takes phosphate and hydrogen ions and is thus reduced to NADPH.

Q22. Define oxidation and reduction reactions.

Ans. Oxidation: Addition of oxygen, removal of hydrogen or the loss of electrons is called oxidation. Oxidation is energy yielding process.

Reduction: Addition of hydrogen, removal of oxygen or the gain of electrons is called reduction. Reduction is energy consuming process.

Q23. Define photolysis.

Ans. Photo means "light", lysis means "breakdown". The breakdown of water molecules in the presence of light to release oxygen is called photolysis. Photolysis occurs in the light reaction (1st phase) of photosynthesis.

Q24. Define photosynthesis.

Ans. The process by which plants and some other autotropic organisms prepare their food (in the form of glucose) in the presence of sunlight and chlorophyll with oxygen as a by-product is called photosynthesis.

OR

In this process, the energy-poor inorganic oxidized compounds of carbon (i.e. CO₂) are reduced to energy rich carbohydrates (i.e. "glucose").

Chemical Equation for photosynthesis.

6CO₂ + 12H₂O + Photon(Sunlight) --Chlorophyll-> C₆H₁₂O₆ + 6O₂ + 6H₂O

It is an anabolic process and nearly all life depends on it.

Q25. Define photosystems.

Ans. Photosynthetic pigments are organized into clusters for efficient absorption and utilization of solar/light energy in thylakoid membranes. These clusters are called photosystems.

Q26. Define pigments. What are its types?

Ans. Pigments are the colored substances that absorb visible light. Different pigments absorb light of different wavelength.

Types of Pigments: Pigments are of two types:

i. Main Photosynthetic pigment: Chlorophyll a is the main photosynthetic pigment.

ii. Accessory pigment: Additional pigments like chlorophyll b and carotenoids are called accessory pigments. Some wavelengths not absorbed by chlorophyll a are very effectively absorbed by accessory pigments and vice versa.

Q27. What is pyruvic acid?

Ans. In the first step of respiration, a molecule of glucose (6-C) is broken down into two molecules of pyruvic acid. It is a (3-C) compound.

Q28. What is respiration / cellular respiration?

Ans. The oxidation of food in order to obtain energy is called respiration. The respiration takes place in a cell called cellular respiration. In cellular respiration, food is oxidized to CO₂, while O₂ is reduced into H₂O.

Q29. Why it is said that all life depends on photosynthesis?

Ans. Photosynthesis is the most important biochemical pathway and nearly all life depends on it. It comprises many coordinated biochemical reactions that occurs in plants, some protists and some bacteria.

Q30. What is Light Independent Reaction (Dark Reaction)?

Ans. During the second phase of photosynthesis, CO₂ is reduced to make glucose. The energy from high energy molecules (ATP & NADPH) is utilized and stored in the bonds of glucose. Since these reactions do not use light directly, they are known as light independent reactions. It takes place in the stroma of chloroplasts.

Q31. What are redox reactions?

Ans. In living organisms, redox reactions involve loss and gain of hydrogen atoms. It means that when a molecule loses a hydrogen atom, it actually loses and electron and similarly when a molecule gains hydrogen atom, it actually gains an electron.

Q32. Who discovered ATP and who proposed it as energy-transfer molecule in the living cell?

Ans. Karl Lohmann discovered ATP in 1929 and Fritz Lipmann in 1941 proposed it as energy transfer molecule in living cell.

Q33. How much energy is released when one phosphate bond breaks in an ATP molecule? / How much energy is released from one mole of ATP?

Ans. 7.3 kilo calories / mole or 7300 calories / mole of ATP is released when one phosphate bond breaks.

Q34. What are the locations for the occurrence of light and dark reactions?

Ans. Light reactions takes place on the thylakoid membranes of the chloroplast. Dark reactions takes place in the stroma of the chloroplast.

Q35. What is the abbreviation of ATP, ADP and AMP.

Ans. ATP: Adenosine Triphosphate

ADP: Adenosine Diphosphate

ATP: Adenosine Monophosphate

Q36. Define anaerobes.

Ans. Some existing bacteria and fungi live in oxygen free environment and respire anaerobically are known as anaerobes.

Q37. Differentiate between photosynthesis and respiration.

Ans. Difference between photosynthesis and respiration is given below:

Characteristics	Photosynthesis	Respiration
Metabolism	Anabolism	Catabolism
Energy investment / production	Investment of light energy to store it in the form of bond energy	Bond energy transformed into chemical energy of ATP
Organisms capable of	Some bacteria, all algae, all plants	All organisms
Site of occurrence	Chloroplasts	In cytoplasm and mitochondria
Time of occurrence	In daytime only, in the presence of light	All the time

Q38. Write down name of two compounds produced during respiration process.

Ans. 1. Water (H₂O) 2. Carbon dioxide (CO₂).