BIO 308 FINAL EXAM 2026 REVIEW QUESTIONS COMPLETE WITH 100% VERIFIED ANSWERS WITH RATIONALES

BIO 308 FINAL EXAM 2026 REVIEW QUESTIONS COMPLETE WITH 100% VERIFIED ANSWERS WITH RATIONALES 1. Consider the redox pair CO2/CH4. Which description is true? A) CO2 is oxidized by CH4 B) CO2 is reduced by CH4 C) CO2 is a resulting product when CH4 is oxidized by another molecule D) CO2 is a resulting product when CH4 is reduced by another molecule CORRECT ANSWER: C RATIONALE: CH4 is the reduced form; when oxidized by another molecule, it produces CO2 as a product. ________________________________________ 2. For the carbon cycle, which bacteria could carry conversion A (CO2 fixation)? A) an aerobic heterotroph like Pseudomonas B) a fermentative heterotroph like Clostridium C) a methanogen like Methanobacterium D) an NH4+ oxidizing bacterium CORRECT ANSWER: D RATIONALE: NH4+ oxidizing bacteria (nitrifiers) fix CO2 as chemoautotrophs. ________________________________________ 3. Nitrification involves: A) reduction of ammonium to nitrites B) oxidation of ammonium to nitrites C) fixation of nitrogen gas to ammonium D) reduction of nitrates to nitrogen gas E) oxidation of nitrates to nitrogen gas CORRECT ANSWER: B RATIONALE: Nitrification is the aerobic oxidation of NH4+ to NO2- then NO3-. ________________________________________ 4. What is the most stable form of nitrogen? A) NO B) NO2- C) N2 D) NH3 E) NH CORRECT ANSWER: C RATIONALE: N2 has a triple bond, making it chemically very stable. ________________________________________ 5. What causes the dead zone in the Gulf of Mexico (O2 2.0 mg/L)? A) High iron concentrations B) Deepwater Horizon oil spill C) High carbon and nitrogen concentrations D) Low oxygen concentrations E) High phosphorus concentrations CORRECT ANSWER: C RATIONALE: Excess C and N from runoff cause algal blooms, then microbial O2 depletion. ________________________________________ 6. The reactions on the right side of the table (e.g., methanogenesis) occur only: A) under thermophilic conditions B) under anaerobic conditions C) deep within Earth's crust D) under aerobic conditions CORRECT ANSWER: B RATIONALE: Methanogenesis and similar reactions are strictly anaerobic. ________________________________________ 7. The term ____ refers to heat energy absorbed or released, whereas ____ is a measure of disorder. A) enthalpy, free energy B) enthalpy, entropy C) entropy, enthalpy D) free energy, entropy E) free energy, enthalpy CORRECT ANSWER: B RATIONALE: Enthalpy (H) is heat content; entropy (S) is disorder. ________________________________________ 8. Which statement is NOT true regarding electron donors in prokaryotic metabolism? A) Use of organic electron donors = organotrophy B) Chemolithotrophy uses inorganic electron donors C) Oxygen can serve as an electron donor D) Electrons can come from H2S CORRECT ANSWER: C RATIONALE: Oxygen is an electron acceptor, not a donor. ________________________________________ 9. An ATP molecule is stabilized when it: A) complexes with Mg2+ B) forms a cyclic molecule C) binds to ribose D) hydrolyzes to ADP CORRECT ANSWER: A RATIONALE: Mg2+ shields negative charges on ATP phosphates. ________________________________________ 10. Pattern of enzyme activity at increasing temperature? A) Bell curve shifted right B) Perfect bell curve C) Sharp increase then levels out D) Linear increase CORRECT ANSWER: A RATIONALE: Activity rises to optimum then declines; curve is skewed right. ________________________________________ 11. Which is/are true about enzymes? A) Catalysts that speed up reactions B) Proteins denatured by pH/temp changes C) Highly specific for substrates D) Two choices correct E) A, B, and C correct CORRECT ANSWER: E RATIONALE: All three statements are correct properties of enzymes. ________________________________________ 12. Greatest amount of reduced NADH+H+ is produced during which stage? A) Glycolysis B) Oxidative phosphorylation C) Pyruvate → Acetyl CoA D) TCA cycle CORRECT ANSWER: D RATIONALE: TCA cycle produces 3 NADH per acetyl CoA. ________________________________________ 13. Chemoorganotrophy describes microorganisms that: A) use CO2 as carbon source B) pull electrons from minerals C) perform photolysis of organics D) use preformed organic compounds for electrons and energy