Bioenergetics β MCQs 50 Score: 0 Attempted: 0/50 Subscribe 1. Bioenergetics is the study of: (A) Heat transfer in metals (B) Energy flow and transformations in living systems (C) Sound propagation in air (D) Radiation therapy in medicine 2. The main energy currency of the cell is: (A) NADH (B) ATP (C) FADH2 (D) GTP 3. ATP contains how many phosphate groups? (A) One (B) Two (C) Three (D) Four 4. Hydrolysis of ATP to ADP is: (A) Endergonic (B) Exergonic (C) Isoenergetic (D) Non-spontaneous 5. The standard free energy change (ΞGΒ°β) of ATP hydrolysis is approximately: (A) β30.5 kJ/mol (B) +30.5 kJ/mol (C) β10 kJ/mol (D) +100 kJ/mol 6. The chemiosmotic theory was proposed by: (A) Albert Szent-GyΓΆrgyi (B) Peter Mitchell (C) Hans Krebs (D) Otto Warburg 7. In mitochondria, ATP synthesis is driven by: (A) Proton gradient across the inner membrane (B) Sodium gradient (C) Calcium transport (D) Potassium current 8. The enzyme responsible for ATP synthesis is: (A) DNA polymerase (B) RNA polymerase (C) ATP synthase (D) Protease 9. The main site of oxidative phosphorylation is: (A) Cytoplasm (B) Inner mitochondrial membrane (C) Golgi apparatus (D) Nucleus 10. Glycolysis occurs in the: (A) Nucleus (B) Cytoplasm (C) Mitochondrial matrix (D) Chloroplast 11. The Krebs cycle takes place in the: (A) Cytoplasm (B) Mitochondrial matrix (C) Endoplasmic reticulum (D) Ribosome 12. The net ATP yield from glycolysis per glucose molecule is: (A) 1 ATP (B) 2 ATP (C) 4 ATP (D) 8 ATP 13. The net ATP yield from complete oxidation of one glucose molecule is about: (A) 12 ATP (B) 24 ATP (C) 30β32 ATP (D) 60 ATP 14. NADH generated in the Krebs cycle donates electrons to: (A) Complex I of the electron transport chain (B) Complex II (C) Complex III (D) Complex IV 15. FADH2 donates electrons to: (A) Complex I (B) Complex II (C) Complex III (D) Complex IV 16. The final electron acceptor in the mitochondrial electron transport chain is: (A) NAD+ (B) Oxygen (C) Carbon dioxide (D) ATP 17. Oxidative phosphorylation is coupled to: (A) Proton transport (B) Protein degradation (C) DNA replication (D) RNA transcription 18. In photosynthesis, ATP is synthesized in: (A) Chloroplast thylakoid membrane (B) Cytoplasm (C) Nucleus (D) Ribosome 19. The light-dependent reactions of photosynthesis generate: (A) ATP and NADPH (B) Glucose (C) Pyruvate (D) FADH2 20. The Calvin cycle is also called the: (A) Light-dependent pathway (B) Dark reaction (C) Glycolysis (D) Krebs cycle 21. Substrate-level phosphorylation occurs in: (A) Glycolysis and Krebs cycle (B) Electron transport chain (C) Calvin cycle (D) DNA replication 22. Uncouplers of oxidative phosphorylation: (A) Inhibit ATP synthase (B) Collapse the proton gradient (C) Block electron transport (D) Increase ATP production 23. The main uncoupling protein in brown adipose tissue is: (A) UCP1 (thermogenin) (B) Cytochrome c (C) ATPase (D) Ferritin 24. Photophosphorylation in plants is analogous to: (A) Glycolysis (B) Oxidative phosphorylation in mitochondria (C) Fermentation (D) DNA replication 25. Cytochrome c is located in: (A) Mitochondrial inner membrane space (B) Nucleus (C) Cytoplasm (D) Chloroplast stroma 26. The P/O ratio represents: (A) ATP molecules synthesized per oxygen atom reduced (B) Protein to oxygen ratio (C) Proton to oxygen ratio (D) Pressure to osmotic ratio 27. The standard redox potential (EΒ°β) indicates: (A) Tendency of a molecule to accept or donate electrons (B) Rate of enzyme turnover (C) Heat capacity (D) pKa value 28. Anaerobic glycolysis results in the production of: (A) Lactic acid or ethanol (B) Acetyl-CoA (C) CO2 and H2O (D) FADH2 29. The enzyme hexokinase catalyzes: (A) Glucose β Glucose-6-phosphate (B) Glucose β Pyruvate (C) Pyruvate β Acetyl-CoA (D) Fructose β FADH2 30. The enzyme phosphofructokinase (PFK) regulates: (A) Glycolysis (B) Krebs cycle (C) Electron transport chain (D) Calvin cycle 31. The Pasteur effect describes: (A) Inhibition of fermentation by oxygen (B) Increase of ATP by fermentation (C) DNA replication in anaerobes (D) Light absorption in photosynthesis 32. Which high-energy compound is an intermediate in glycolysis? (A) 1,3-Bisphosphoglycerate (B) Lactate (C) FADH2 (D) CO2 33. In oxidative phosphorylation, ATP yield per NADH is approximately: (A) 1 ATP (B) 2.5 ATP (C) 3.5 ATP (D) 5 ATP 34. In oxidative phosphorylation, ATP yield per FADH2 is approximately: (A) 1 ATP (B) 1.5 ATP (C) 2.5 ATP (D) 3 ATP 35. Chemiosmotic coupling involves: (A) Proton motive force (B) Ion channel proteins (C) DNA helicases (D) Heat shock proteins 36. The main metabolic fuel for the brain under normal conditions is: (A) Glucose (B) Fatty acids (C) Amino acids (D) Ketone bodies 37. During prolonged fasting, the brain can also use: (A) Ketone bodies (B) FADH2 (C) NADH (D) Lactic acid 38. Fermentation allows ATP production without: (A) Oxygen (B) Glucose (C) NADH (D) Enzymes 39. The enzyme lactate dehydrogenase catalyzes: (A) Pyruvate β Lactate (B) Glucose β Glucose-6-phosphate (C) NADH β NADPH (D) ATP β ADP 40. The Warburg effect describes: (A) Cancer cells preferring glycolysis even in oxygen presence (B) Oxygen inhibition of photosynthesis (C) Heat generation in brown fat (D) High ATP yield in muscle 41. ATP can also be produced in the cytoplasm by: (A) Substrate-level phosphorylation (B) Oxidative phosphorylation (C) Photophosphorylation (D) Redox titration 42. NADH shuttles (e.g., malate-aspartate shuttle) are needed to: (A) Transport electrons into mitochondria (B) Pump protons out of the cell (C) Carry ATP into nucleus (D) Reduce FAD to FADH2 43. The Cori cycle connects: (A) Muscle glycolysis and liver gluconeogenesis (B) Photosynthesis and respiration (C) DNA replication and transcription (D) Protein folding and degradation 44. Photophosphorylation in plants involves: (A) Photosystem I and II (B) Only Photosystem I (C) Only Photosystem II (D) ATP synthase without photosystems 45. Cyclic photophosphorylation produces: (A) ATP only (B) ATP and NADPH (C) Glucose (D) Pyruvate 46. Non-cyclic photophosphorylation produces: (A) ATP and NADPH (B) Only ATP (C) Only NADPH (D) Glucose 47. The proton motive force has two components: (A) pH gradient and electrical potential (B) Temperature and pressure (C) Osmotic and hydrostatic pressure (D) Free energy and entropy 48. Oxidative phosphorylation is inhibited by: (A) Cyanide and carbon monoxide (B) Glucose (C) ATP (D) Oxygen 49. The enzyme complex that produces water in mitochondria is: (A) Complex I (B) Complex II (C) Complex III (D) Complex IV (Cytochrome c oxidase) 50. 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