BIO 202 EXAM 2 PRACTICE EXAM – QUESTIONS AND ANSWERS | VERIFIED AND
WELL DETAILED ANSWERS | PLUS RATIONALES | DOWNLOAD AND PASS |
LATEST EXAM UPDATE 2026/2027
Core Domains
Cellular Respiration and Metabolism
Photosynthesis and Plant Physiology
Cell Signaling and Communication
The Cell Cycle and Cell Division
Genetics and Inheritance Patterns
Molecular Biology and Gene Expression
DNA Replication, Repair, and Mutation
Biotechnology and Laboratory Techniques
Evolutionary Biology and Population Genetics
Ethics and Regulatory Compliance in Biological Research
Introduction
This practice examination is designed to assess comprehensive understanding of core
biological concepts typically covered in a second-semester biology course. It evaluates
knowledge of cellular processes, genetic mechanisms, molecular biology, and applied
laboratory techniques. The exam utilizes multiple-choice and scenario-based
questions to test both foundational theory and real-world application. Emphasis is
placed on critical thinking, data interpretation, ethical decision-making, and
professional standards. This assessment prepares students for advanced study and
careers in biological sciences, healthcare, and research, ensuring mastery of essential
competencies required for academic and professional success.
SECTION ONE: QUESTIONS 1–50
,1. Which of the following best describes the primary role of NAD+ in cellular
respiration?
A. It serves as the final electron acceptor in the electron transport chain.
B. It acts as a coenzyme that carries electrons to the electron transport chain.
C. It directly phosphorylates ADP to form ATP.
D. It catalyzes the breakdown of glucose into pyruvate.
🟢 Correct Answer: B. It acts as a coenzyme that carries electrons to the electron
transport chain.
🔴 Explanation: NAD+ functions as an electron carrier, accepting electrons during
glycolysis and the Krebs cycle to form NADH, which then delivers electrons to the
electron transport chain.
2. A patient presents with a genetic disorder caused by a mutation in a
mitochondrial gene. Which inheritance pattern is most likely?
A. Autosomal dominant
B. Autosomal recessive
C. Maternal inheritance
D. X-linked recessive
🟢 Correct Answer: C. Maternal inheritance
🔴 Explanation: Mitochondrial DNA is inherited exclusively from the mother, so
mutations in mitochondrial genes follow a maternal inheritance pattern.
3. During which phase of the cell cycle does DNA replication occur?
A. G1 phase
B. S phase
C. G2 phase
D. M phase
,🟢 Correct Answer: B. S phase
🔴 Explanation: DNA replication takes place during the S (synthesis) phase of
interphase, ensuring that each daughter cell receives a complete set of
chromosomes.
4. Which enzyme is responsible for unwinding the DNA double helix during
replication?
A. DNA polymerase
B. Helicase
C. Ligase
D. Primase
🟢 Correct Answer: B. Helicase
🔴 Explanation: Helicase breaks the hydrogen bonds between complementary
base pairs, separating the DNA strands to allow replication to proceed.
5. In a cross between two heterozygous tall pea plants (Tt), what is the expected
phenotypic ratio of tall to short offspring?
A. 1:1
B. 3:1
C. 1:2:1
D. 9:3:3:1
🟢 Correct Answer: B. 3:1
🔴 Explanation: A monohybrid cross between two heterozygotes yields a 3:1
phenotypic ratio, with three tall plants for every short plant.
6. Which of the following is a key difference between mitosis and meiosis?
A. Mitosis produces haploid cells, while meiosis produces diploid cells.
B. Meiosis involves one round of division, while mitosis involves two.
, C. Mitosis produces genetically identical cells, while meiosis produces genetically
diverse cells.
D. Mitosis occurs only in gametes, while meiosis occurs in somatic cells.
🟢 Correct Answer: C. Mitosis produces genetically identical cells, while meiosis
produces genetically diverse cells.
🔴 Explanation: Mitosis generates two identical diploid cells, whereas meiosis
produces four genetically unique haploid cells through crossing over and
independent assortment.
7. A researcher discovers a new organism that lacks a nucleus. To which domain
does this organism most likely belong?
A. Eukarya
B. Archaea
C. Plantae
D. Fungi
🟢 Correct Answer: B. Archaea
🔴 Explanation: Organisms lacking a nucleus are prokaryotes, which belong to the
domains Bacteria or Archaea. Archaea often inhabit extreme environments and are
distinct from bacteria.
8. Which of the following best explains why ATP is considered the "energy
currency" of the cell?
A. It is the most abundant molecule in the cell.
B. It can be easily hydrolyzed to release energy for cellular processes.
C. It is permanently stored in the mitochondria.
D. It can only be produced in the presence of oxygen.
🟢 Correct Answer: B. It can be easily hydrolyzed to release energy for cellular
processes.
WELL DETAILED ANSWERS | PLUS RATIONALES | DOWNLOAD AND PASS |
LATEST EXAM UPDATE 2026/2027
Core Domains
Cellular Respiration and Metabolism
Photosynthesis and Plant Physiology
Cell Signaling and Communication
The Cell Cycle and Cell Division
Genetics and Inheritance Patterns
Molecular Biology and Gene Expression
DNA Replication, Repair, and Mutation
Biotechnology and Laboratory Techniques
Evolutionary Biology and Population Genetics
Ethics and Regulatory Compliance in Biological Research
Introduction
This practice examination is designed to assess comprehensive understanding of core
biological concepts typically covered in a second-semester biology course. It evaluates
knowledge of cellular processes, genetic mechanisms, molecular biology, and applied
laboratory techniques. The exam utilizes multiple-choice and scenario-based
questions to test both foundational theory and real-world application. Emphasis is
placed on critical thinking, data interpretation, ethical decision-making, and
professional standards. This assessment prepares students for advanced study and
careers in biological sciences, healthcare, and research, ensuring mastery of essential
competencies required for academic and professional success.
SECTION ONE: QUESTIONS 1–50
,1. Which of the following best describes the primary role of NAD+ in cellular
respiration?
A. It serves as the final electron acceptor in the electron transport chain.
B. It acts as a coenzyme that carries electrons to the electron transport chain.
C. It directly phosphorylates ADP to form ATP.
D. It catalyzes the breakdown of glucose into pyruvate.
🟢 Correct Answer: B. It acts as a coenzyme that carries electrons to the electron
transport chain.
🔴 Explanation: NAD+ functions as an electron carrier, accepting electrons during
glycolysis and the Krebs cycle to form NADH, which then delivers electrons to the
electron transport chain.
2. A patient presents with a genetic disorder caused by a mutation in a
mitochondrial gene. Which inheritance pattern is most likely?
A. Autosomal dominant
B. Autosomal recessive
C. Maternal inheritance
D. X-linked recessive
🟢 Correct Answer: C. Maternal inheritance
🔴 Explanation: Mitochondrial DNA is inherited exclusively from the mother, so
mutations in mitochondrial genes follow a maternal inheritance pattern.
3. During which phase of the cell cycle does DNA replication occur?
A. G1 phase
B. S phase
C. G2 phase
D. M phase
,🟢 Correct Answer: B. S phase
🔴 Explanation: DNA replication takes place during the S (synthesis) phase of
interphase, ensuring that each daughter cell receives a complete set of
chromosomes.
4. Which enzyme is responsible for unwinding the DNA double helix during
replication?
A. DNA polymerase
B. Helicase
C. Ligase
D. Primase
🟢 Correct Answer: B. Helicase
🔴 Explanation: Helicase breaks the hydrogen bonds between complementary
base pairs, separating the DNA strands to allow replication to proceed.
5. In a cross between two heterozygous tall pea plants (Tt), what is the expected
phenotypic ratio of tall to short offspring?
A. 1:1
B. 3:1
C. 1:2:1
D. 9:3:3:1
🟢 Correct Answer: B. 3:1
🔴 Explanation: A monohybrid cross between two heterozygotes yields a 3:1
phenotypic ratio, with three tall plants for every short plant.
6. Which of the following is a key difference between mitosis and meiosis?
A. Mitosis produces haploid cells, while meiosis produces diploid cells.
B. Meiosis involves one round of division, while mitosis involves two.
, C. Mitosis produces genetically identical cells, while meiosis produces genetically
diverse cells.
D. Mitosis occurs only in gametes, while meiosis occurs in somatic cells.
🟢 Correct Answer: C. Mitosis produces genetically identical cells, while meiosis
produces genetically diverse cells.
🔴 Explanation: Mitosis generates two identical diploid cells, whereas meiosis
produces four genetically unique haploid cells through crossing over and
independent assortment.
7. A researcher discovers a new organism that lacks a nucleus. To which domain
does this organism most likely belong?
A. Eukarya
B. Archaea
C. Plantae
D. Fungi
🟢 Correct Answer: B. Archaea
🔴 Explanation: Organisms lacking a nucleus are prokaryotes, which belong to the
domains Bacteria or Archaea. Archaea often inhabit extreme environments and are
distinct from bacteria.
8. Which of the following best explains why ATP is considered the "energy
currency" of the cell?
A. It is the most abundant molecule in the cell.
B. It can be easily hydrolyzed to release energy for cellular processes.
C. It is permanently stored in the mitochondria.
D. It can only be produced in the presence of oxygen.
🟢 Correct Answer: B. It can be easily hydrolyzed to release energy for cellular
processes.
