Formation of ATP MCQs With Answer

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Formation of ATP MCQs With Answer
Understanding the formation of ATP is essential for B.Pharm students studying bioenergetics, pharmacology, and cellular metabolism. This focused introduction covers ATP synthesis mechanisms—substrate-level phosphorylation and oxidative phosphorylation—highlighting mitochondrial electron transport chain (ETC), chemiosmotic theory, ATP synthase (F0F1), proton motive force, and regulation by ADP/ATP ratios. It also touches on clinical and pharmacological relevance: inhibitors, uncouplers, and mitochondrial dysfunctions affecting drug action. These targeted ATP MCQs with answers will reinforce core concepts, improve exam readiness, and connect biochemical pathways to pharmaceutical implications. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which process directly synthesizes ATP during glycolysis?

  • Oxidative phosphorylation
  • Substrate-level phosphorylation
  • Photophosphorylation
  • Cyclic phosphorylation

Correct Answer: Substrate-level phosphorylation

Q2. The chemiosmotic theory for ATP formation was proposed by which scientist?

  • Emil Fischer
  • Peter Mitchell
  • Otto Warburg
  • Hans Krebs

Correct Answer: Peter Mitchell

Q3. ATP synthase is also known as which complex of the electron transport chain?

  • Complex I
  • Complex II
  • Complex IV
  • Complex V

Correct Answer: Complex V

Q4. Which component generates the proton motive force used for ATP synthesis?

  • ATP synthase rotor
  • Electron transport chain proton pumps
  • Substrate-level enzymes in cytosol
  • Glycolytic ATPase

Correct Answer: Electron transport chain proton pumps

Q5. Which molecule directly donates phosphate to ADP during substrate-level phosphorylation in glycolysis?

  • Glyceraldehyde-3-phosphate
  • 1,3-Bisphosphoglycerate
  • Fructose-1,6-bisphosphate
  • Phosphofructokinase

Correct Answer: 1,3-Bisphosphoglycerate

Q6. The Fo portion of ATP synthase is primarily responsible for which function?

  • ATP synthesis catalytic activity
  • Electron transfer
  • Proton translocation across the membrane
  • Transport of ADP into mitochondria

Correct Answer: Proton translocation across the membrane

Q7. Which inhibitor blocks ATP synthase by binding to the Fo subunit?

  • Rotenone
  • Oligomycin
  • Antimycin A
  • Cyanide

Correct Answer: Oligomycin

Q8. Uncouplers like 2,4-dinitrophenol (DNP) decrease ATP production by:

  • Blocking Complex I
  • Increasing proton leak across inner mitochondrial membrane
  • Inhibiting ATP synthase catalytic site
  • Preventing ADP entry into mitochondria

Correct Answer: Increasing proton leak across inner mitochondrial membrane

Q9. The adenine nucleotide translocase (ANT) in the inner mitochondrial membrane exchanges:

  • ATP for ADP across the IMM
  • Protons for hydroxide ions
  • Pi for ATP
  • NADH for NAD+

Correct Answer: ATP for ADP across the IMM

Q10. Which complex of the ETC is inhibited by rotenone?

  • Complex I
  • Complex II
  • Complex III
  • Complex IV

Correct Answer: Complex I

Q11. The typical P/O ratio for NADH oxidation is closest to:

  • 1.0
  • 1.5
  • 2.5
  • 4.0

Correct Answer: 2.5

Q12. In mitochondria, inorganic phosphate (Pi) uptake into the matrix is coupled to which ion?

  • Sodium (Na+)
  • Proton (H+)
  • Potassium (K+)
  • Calcium (Ca2+)

Correct Answer: Proton (H+)

Q13. Which reaction represents the hydrolysis of ATP with standard free energy change?

  • ATP → ADP + Pi, ΔG°’ around −30.5 kJ/mol
  • ATP → AMP + PPi, ΔG°’ around +30 kJ/mol
  • ADP → AMP + Pi, ΔG°’ around +50 kJ/mol
  • ATP → ADP + Pi, ΔG°’ around +30.5 kJ/mol

Correct Answer: ATP → ADP + Pi, ΔG°’ around −30.5 kJ/mol

Q14. Which enzyme regenerates ATP from ADP rapidly in muscle cells?

  • Adenylate kinase
  • Creatine kinase
  • Hexokinase
  • Lactate dehydrogenase

Correct Answer: Creatine kinase

Q15. Adenylate kinase catalyzes which reaction important for cellular energy balance?

  • ATP + Pi → ADP + H2O
  • 2 ADP ↔ ATP + AMP
  • AMP + Pi → ADP
  • ATP → ADP + Pi

Correct Answer: 2 ADP ↔ ATP + AMP

Q16. Which complex contains cytochrome c oxidase activity?

  • Complex I
  • Complex II
  • Complex III
  • Complex IV

Correct Answer: Complex IV

Q17. Which of the following directly accepts electrons from FADH2 in the ETC?

  • Complex I
  • Complex II
  • Complex III
  • Complex IV

Correct Answer: Complex II

Q18. The primary driving force for ATP synthase rotation is:

  • Electron flow through ATP synthase
  • Proton gradient (ΔpH and Δψ) across inner mitochondrial membrane
  • ATP concentration in cytosol
  • Oxygen concentration in matrix

Correct Answer: Proton gradient (ΔpH and Δψ) across inner mitochondrial membrane

Q19. Which statement best describes substrate-level phosphorylation?

  • ATP formation coupled to electron transport
  • ATP formed by direct transfer of phosphate from a phosphorylated intermediate to ADP
  • ATP generation by light-driven proton pumps
  • ATP formed within ATP synthase without substrate involvement

Correct Answer: ATP formed by direct transfer of phosphate from a phosphorylated intermediate to ADP

Q20. Glycolytic ATP yield per glucose molecule via substrate-level phosphorylation (net) is:

  • 4 ATP
  • 2 ATP
  • 6 ATP
  • 3 ATP

Correct Answer: 2 ATP

Q21. Which transporter in the inner mitochondrial membrane moves inorganic phosphate into the matrix?

  • Phosphate carrier (Pi carrier)
  • ADP/ATP translocase
  • Porin
  • Glucose transporter

Correct Answer: Phosphate carrier (Pi carrier)

Q22. In oxidative phosphorylation, which ion gradient is most important for ATP synthesis?

  • Sodium gradient
  • Calcium gradient
  • Proton gradient
  • Chloride gradient

Correct Answer: Proton gradient

Q23. Antimycin A inhibits which ETC complex leading to decreased ATP production?

  • Complex I
  • Complex II
  • Complex III
  • Complex IV

Correct Answer: Complex III

Q24. Cyanide toxicity blocks which step, causing rapid cessation of ATP synthesis?

  • Electron transfer to oxygen at Complex IV
  • Electron transfer at Complex I
  • Uptake of phosphate into mitochondria
  • Substrate-level phosphorylation in glycolysis

Correct Answer: Electron transfer to oxygen at Complex IV

Q25. Which cytosolic process provides reducing equivalents (NADH) that must be shuttled into mitochondria for ATP production?

  • Glycolysis
  • β-oxidation
  • Citric acid cycle
  • Oxidative phosphorylation

Correct Answer: Glycolysis

Q26. The malate-aspartate shuttle primarily transfers which reducing equivalent into mitochondria?

  • FADH2
  • NADH equivalents
  • ATP
  • Pi

Correct Answer: NADH equivalents

Q27. Which of the following increases when ATP demand rises in a cell?

  • ATP/ADP ratio
  • ADP concentration
  • Oxygen inhibition of ETC
  • Inhibition of ATP synthase

Correct Answer: ADP concentration

Q28. Which mitochondrial membrane is the site of the electron transport chain and ATP synthesis?

  • Outer mitochondrial membrane
  • Inner mitochondrial membrane
  • Mitochondrial matrix membrane
  • Intermembrane matrix

Correct Answer: Inner mitochondrial membrane

Q29. The rotor mechanism of ATP synthase converts what into mechanical rotation?

  • Nucleotide binding
  • Proton flow through Fo
  • ATP hydrolysis
  • Electron flow

Correct Answer: Proton flow through Fo

Q30. Oxidation of one molecule of acetyl-CoA via the citric acid cycle generates directly how many NADH and FADH2 molecules respectively?

  • 3 NADH and 1 FADH2
  • 2 NADH and 2 FADH2
  • 1 NADH and 3 FADH2
  • 4 NADH and 0 FADH2

Correct Answer: 3 NADH and 1 FADH2

Q31. Which of the following best describes P/O ratio?

  • ATP yield per oxygen atom reduced
  • ATP yield per oxygen molecule (O2) reduced
  • Phosphate/oxygen transport rate
  • Proton/oxygen gradient

Correct Answer: ATP yield per oxygen molecule (O2) reduced

Q32. Which metabolite inhibits ATP synthase by decreasing availability of ADP?

  • High AMP levels
  • High ATP levels
  • High Pi levels
  • High ADP levels

Correct Answer: High ATP levels

Q33. The F1 portion of ATP synthase is located in which compartment?

  • Intermembrane space
  • Matrix side of inner membrane
  • Outer membrane surface
  • Cytosol

Correct Answer: Matrix side of inner membrane

Q34. Which process contributes directly to maintaining the mitochondrial inner membrane potential?

  • ATP hydrolysis in cytosol
  • Proton pumping by ETC complexes I, III, and IV
  • Movement of glucose into mitochondria
  • Substrate-level phosphorylation in cytosol

Correct Answer: Proton pumping by ETC complexes I, III, and IV

Q35. Which molecule is the final electron acceptor in the electron transport chain?

  • NAD+
  • Oxygen
  • FAD
  • Carbon dioxide

Correct Answer: Oxygen

Q36. Thermodynamically, ATP synthesis by ATP synthase is driven by coupling ADP + Pi with:

  • Heat release
  • Proton gradient energy (Δp)
  • Direct electron transfer
  • Substrate concentration only

Correct Answer: Proton gradient energy (Δp)

Q37. Which condition would increase ATP production by oxidative phosphorylation?

  • Inhibition of Complex IV
  • Decreased oxygen availability
  • Increased ADP availability
  • Presence of uncouplers

Correct Answer: Increased ADP availability

Q38. Which enzyme mediates the irreversible conversion of glucose to glucose-6-phosphate and consumes ATP?

  • Hexokinase
  • Phosphofructokinase-1
  • Pyruvate kinase
  • Glyceraldehyde-3-phosphate dehydrogenase

Correct Answer: Hexokinase

Q39. Which mitochondrial disease mechanism can lead to decreased ATP production?

  • Enhanced proton pumping
  • Mutations in ETC complexes
  • Overexpression of ATP synthase
  • Increased oxygen supply

Correct Answer: Mutations in ETC complexes

Q40. Which statement about oxidative phosphorylation inhibitors is true?

  • Uncouplers increase ATP synthesis efficiency
  • Rotenone blocks Complex III
  • Antimycin A blocks electron transfer at Complex III
  • Oligomycin increases proton flow through Fo

Correct Answer: Antimycin A blocks electron transfer at Complex III

Q41. During hypoxia, cells rely more on which ATP-generating pathway?

  • Oxidative phosphorylation
  • Substrate-level phosphorylation (glycolysis)
  • β-oxidation in mitochondria
  • Photophosphorylation

Correct Answer: Substrate-level phosphorylation (glycolysis)

Q42. Which coenzyme supplies electrons to complex I in the ETC?

  • FADH2
  • NADH
  • Ubiquinone directly
  • Heme a3

Correct Answer: NADH

Q43. The term “proton motive force” includes which two components?

  • ΔG and ΔH
  • ΔpH and membrane potential (Δψ)
  • ATP and ADP concentrations
  • Oxygen and carbon dioxide levels

Correct Answer: ΔpH and membrane potential (Δψ)

Q44. Which process consumes ATP in nucleotide biosynthesis?

  • Ribose-5-phosphate isomerization
  • Activation of precursors via phosphorylation
  • Base pairing in DNA
  • Spontaneous nucleotide assembly

Correct Answer: Activation of precursors via phosphorylation

Q45. Which described mechanism allows mitochondria to regulate ATP synthesis rate rapidly?

  • Transcriptional upregulation only
  • Allosteric regulation by ADP/ATP levels
  • Permanent activation of ATP synthase
  • Changing mitochondrial DNA sequence

Correct Answer: Allosteric regulation by ADP/ATP levels

Q46. In oxidative phosphorylation, which mobile carrier transports electrons between complexes I/II and III?

  • Cytochrome c
  • Succinate
  • Ubiquinone (coenzyme Q)
  • Oxygen

Correct Answer: Ubiquinone (coenzyme Q)

Q47. Which experimental measurement is commonly used to estimate cellular ATP levels?

  • Oxygen consumption rate (OCR) only
  • Luminescence assays using luciferase
  • Glucose uptake measurement
  • Electron microscopy

Correct Answer: Luminescence assays using luciferase

Q48. Which drug class can impair ATP formation by inhibiting mitochondrial complex I and is used as pesticide?

  • Sulfonylureas
  • Rotenone-type pesticides
  • Statins
  • Beta blockers

Correct Answer: Rotenone-type pesticides

Q49. The efficiency of ATP synthesis in mitochondria can be reduced by which of the following?

  • Intact inner membrane and tight coupling
  • Presence of uncoupling proteins
  • High ADP availability
  • Optimal oxygen supply

Correct Answer: Presence of uncoupling proteins

Q50. Overall, the complete aerobic oxidation of one glucose molecule yields approximately how many ATP molecules in most eukaryotic cells?

  • 10–12 ATP
  • 30–32 ATP
  • 50–60 ATP
  • 100 ATP

Correct Answer: 30–32 ATP

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