BCH 2026/2027 Practice Exam Questions COMPLETE SOLUTIONS (18pages)

The standard free energy change for the hydrolysis of GTP (guanosine triphosphate) to GDP + Pi is - 7.3 kcal/mol, similar to that for ATP. From this information, once can conclude the Select one: a. free energy of GDP and phosphate is higher than the free energy of GTP. b. reaction is exergonic c. reaction is endergonic d. reaction requires energy - ✔✔b. reaction is exergonic Refer to the figure below. Which word best fits into this figure where the question mark is located? Select one: a. Metabolism b. Catalysis c. Energy d. Equilibrium - ✔✔c. Energy The high energy phosphate bond in ATP is _____ and ____ energy to break the bond. Select one: a. Hard to break, releases b. Hard to break, requires c. Easy to break, requires d. Easy to break, releases - ✔✔c. Easy to break, requires Match the complexes from the electron transport chain with their direct source of electrons. Complex III Complex I Complex IV Complex II - ✔✔Complex III -> Ubiquinone/Coenzyme Q Complex I -> NADH Complex IV -> Cytochrome C Complex II -> Succinate/FADH2 Which of the following redox couples has the strongest affinity for electrons? Select one: Cytochrome c Fe3+ / cytochrome c Fe2+ O2 / H2O FAD / FADH2 NAD+ / NADH - ✔✔O2 / H2O In a theoretical cell type in which has the electron carriers listed below. Based on their standard reduction potentials (E'°) in the table below. In which order are the electron carriers most likely to act in carrying electrons? Oxidant Reductant E`(V) A+ AH -0.32 B1(oxidised) B2(reduced) -0.62 C3+ C2+ +0.22 D1 D2(oxidised) +0.89 E1(oxidised) E2(FPa)(reduced) +0.77 Select one: a. D1→ B1 → A+→ C3+ → E1 b. E1 → C3+ → A+ → B1 → D1 c. B1 → A+ → C3+→ E1 → D1 d. B1 → D1→ A+ → C3+ → E1 - ✔✔c. B1 → A+ → C3+→ E1 → D1 Although molecular oxygen does not participate directly in any of the reactions in the citric acid cycle, the cycle operates only when oxygen is present. This is because oxygen: Select one: A. Accepts electrons from the electron transport chain, allowing reoxidation of NADH to NAD+ B. Is necessary for producing water, which is crucial for all cellular processes C. Removes toxic by-products of the citric acid cycle D. Is necessary as an activator of enzymes of the cycle - ✔✔A. Accepts electrons from the electron transport chain, allowing reoxidation of NADH to NAD+ Acetyl CoA Select one: A. Undergoes carboxylation to form malate B. Levels regulate the rate of the citric acid cycle C. Contains a high energy thioester linkage D. Activates the enzyme pyruvate dehydrogenase - ✔✔C. Contains a high energy thioester linkage The Citric Acid Cycl