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.
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.
