BIO 250 Exam 150 Questions
with Answers and Rationales
PRACTICE EXAM REVIEWS
WITH COMPLETE ACTUAL
EXAM 2025-2026 QUESTIONS
AND CORRECT VERIFIED
ANSWERS/ ALREADY GRADED
A+ (MOST RECENT!!)
1. Which organelle is primarily responsible for ATP production in
eukaryotic cells?
A. Ribosome
B. Lysosome
C. Mitochondrion
D. Golgi apparatus
Answer: C. Mitochondrion
Rationale: Mitochondria generate ATP through aerobic cellular
respiration and oxidative phosphorylation.
,2. Which phase of mitosis is characterized by chromosome
alignment at the cell equator?
A. Prophase
B. Metaphase
C. Anaphase
D. Telophase
Answer: B. Metaphase
Rationale: During metaphase, chromosomes align along the
metaphase plate before separation.
3. DNA replication occurs during which phase of the cell cycle?
A. G1
B. G2
C. M
D. S
Answer: D. S
Rationale: The synthesis (S) phase is when DNA is replicated in
preparation for cell division.
4. Which nitrogenous base is found in RNA but not DNA?
A. Thymine
B. Cytosine
C. Guanine
D. Uracil
Answer: D. Uracil
Rationale: RNA contains uracil instead of thymine.
,5. Which enzyme synthesizes RNA from a DNA template?
A. DNA polymerase
B. Ligase
C. Helicase
D. RNA polymerase
Answer: D. RNA polymerase
Rationale: RNA polymerase catalyzes transcription.
6. The functional unit of heredity is the:
A. Chromosome
B. Allele
C. Gene
D. Nucleotide
Answer: C. Gene
Rationale: A gene is a DNA segment that codes for a functional
product.
7. Which process produces four genetically unique daughter cells?
A. Mitosis
B. Binary fission
C. Meiosis
D. Cytokinesis
Answer: C. Meiosis
Rationale: Meiosis generates four haploid gametes with genetic
variation.
8. The plasma membrane is primarily composed of:
, A. Protein only
B. Carbohydrates
C. Phospholipid bilayer
D. Cellulose
Answer: C. Phospholipid bilayer
Rationale: The membrane consists mainly of phospholipids with
embedded proteins.
9. Osmosis is the movement of:
A. Solutes across a membrane
B. Oxygen into cells
C. Water across a selectively permeable membrane
D. Proteins by active transport
Answer: C. Water across a selectively permeable membrane
Rationale: Osmosis is the passive movement of water toward higher
solute concentration.
10. Which macromolecule provides the primary long-term energy
storage?
A. Proteins
B. Carbohydrates
C. Lipids
D. Nucleic acids
Answer: C. Lipids
Rationale: Lipids store energy efficiently due to their high energy
density.
with Answers and Rationales
PRACTICE EXAM REVIEWS
WITH COMPLETE ACTUAL
EXAM 2025-2026 QUESTIONS
AND CORRECT VERIFIED
ANSWERS/ ALREADY GRADED
A+ (MOST RECENT!!)
1. Which organelle is primarily responsible for ATP production in
eukaryotic cells?
A. Ribosome
B. Lysosome
C. Mitochondrion
D. Golgi apparatus
Answer: C. Mitochondrion
Rationale: Mitochondria generate ATP through aerobic cellular
respiration and oxidative phosphorylation.
,2. Which phase of mitosis is characterized by chromosome
alignment at the cell equator?
A. Prophase
B. Metaphase
C. Anaphase
D. Telophase
Answer: B. Metaphase
Rationale: During metaphase, chromosomes align along the
metaphase plate before separation.
3. DNA replication occurs during which phase of the cell cycle?
A. G1
B. G2
C. M
D. S
Answer: D. S
Rationale: The synthesis (S) phase is when DNA is replicated in
preparation for cell division.
4. Which nitrogenous base is found in RNA but not DNA?
A. Thymine
B. Cytosine
C. Guanine
D. Uracil
Answer: D. Uracil
Rationale: RNA contains uracil instead of thymine.
,5. Which enzyme synthesizes RNA from a DNA template?
A. DNA polymerase
B. Ligase
C. Helicase
D. RNA polymerase
Answer: D. RNA polymerase
Rationale: RNA polymerase catalyzes transcription.
6. The functional unit of heredity is the:
A. Chromosome
B. Allele
C. Gene
D. Nucleotide
Answer: C. Gene
Rationale: A gene is a DNA segment that codes for a functional
product.
7. Which process produces four genetically unique daughter cells?
A. Mitosis
B. Binary fission
C. Meiosis
D. Cytokinesis
Answer: C. Meiosis
Rationale: Meiosis generates four haploid gametes with genetic
variation.
8. The plasma membrane is primarily composed of:
, A. Protein only
B. Carbohydrates
C. Phospholipid bilayer
D. Cellulose
Answer: C. Phospholipid bilayer
Rationale: The membrane consists mainly of phospholipids with
embedded proteins.
9. Osmosis is the movement of:
A. Solutes across a membrane
B. Oxygen into cells
C. Water across a selectively permeable membrane
D. Proteins by active transport
Answer: C. Water across a selectively permeable membrane
Rationale: Osmosis is the passive movement of water toward higher
solute concentration.
10. Which macromolecule provides the primary long-term energy
storage?
A. Proteins
B. Carbohydrates
C. Lipids
D. Nucleic acids
Answer: C. Lipids
Rationale: Lipids store energy efficiently due to their high energy
density.
