, BIOL 101 MODULE 4 EXAM
Essential Biology I w/Lab
Portage Learning
100-Question Practice Examination
2026/2027 Edition
BIOL 101 Module 4 Exam | Essential Biology I w/Lab | Portage Learning | Q & A | 2026/2027
Edition (PDF)
Directions: Select the best answer for each question. This original study assessment is aligned to Module 4 topics
including the cell cycle, mitosis, meiosis, heredity, inheritance, genetic crosses, genetic disorders, and cell-cycle
dysregulation.
1. A diploid somatic cell contains 12 chromosomes. How many chromosomes should each daughter
cell contain after a normal mitotic division?
A) 12
B) 24
C) 48
D) 6
Correct Answer: A) 12
Rationale: Mitosis preserves chromosome number. After DNA replication, sister chromatids separate so that
each daughter cell receives one complete copy of every chromosome, restoring the original diploid count of 12
rather than halving or doubling it.
2. A cell enters mitosis with replicated chromosomes. What holds the two sister chromatids together
most directly before their separation?
A) Ribosomes
B) Lysosomes
C) Cohesin proteins
D) Gap junctions
Correct Answer: C) Cohesin proteins
Rationale: Cohesin complexes physically link sister chromatids after DNA replication. Their regulated removal
allows chromatids to separate at anaphase. Ribosomes synthesize proteins, lysosomes digest cellular material,
and gap junctions mediate communication between adjacent animal cells.
3. Which event defines metaphase of mitosis?
A) Nuclear envelopes reform
B) DNA replication begins
C) Chromosomes align at the metaphase plate
D) Homologous chromosomes pair
BIOL 101 Module 4 Practice Examination | 2026/2027 Edition Page 1
, Correct Answer: C) Chromosomes align at the metaphase plate
Rationale: In metaphase, duplicated chromosomes align at the cell equator with sister kinetochores attached to
opposite spindle poles. Nuclear-envelope reformation occurs in telophase, homologous pairing is characteristic of
meiotic prophase I, and DNA replication precedes mitosis.
4. At the end of mitotic anaphase, what has happened to sister chromatids?
A) They have decondensed completely
B) They have paired with homologs
C) They have separated and moved toward opposite poles
D) They have replicated again
Correct Answer: C) They have separated and moved toward opposite poles
Rationale: Anaphase begins when sister chromatid cohesion is released, allowing spindle forces to move the
chromatids toward opposite poles. Homolog pairing is meiotic, DNA replication occurs before mitosis, and full
chromosome decondensation is associated with telophase.
5. Loss of a functional tumor-suppressor protein is most likely to have which effect?
A) Reduced restraint on cell-cycle progression
B) Guaranteed activation of meiosis
C) Permanent prevention of mutation
D) Immediate chromosome replication arrest in all cells
Correct Answer: A) Reduced restraint on cell-cycle progression
Rationale: Tumor-suppressor proteins normally restrain proliferation, promote repair, or trigger cell death when
damage is severe. Loss of that restraint can permit abnormal cell-cycle progression. It does not automatically
initiate meiosis or guarantee either replication arrest or mutation prevention.
6. In animal cells, the contractile ring that drives cytokinesis is composed primarily of which
cytoskeletal components?
A) Keratin and laminin
B) Tubulin and dynein only
C) Collagen and elastin
D) Actin and myosin
Correct Answer: D) Actin and myosin
Rationale: Animal-cell cytokinesis is driven by an actin-myosin contractile ring that constricts the plasma
membrane to form a cleavage furrow. Tubulin is central to the spindle, while collagen, elastin, keratin, and laminin
are not the primary machinery of the contractile ring.
7. What is the principal purpose of chromosome condensation during mitosis?
A) To translate more proteins
B) To facilitate safe and efficient chromosome movement
C) To dissolve spindle fibers
D) To increase the amount of DNA
BIOL 101 Module 4 Practice Examination | 2026/2027 Edition Page 2
Essential Biology I w/Lab
Portage Learning
100-Question Practice Examination
2026/2027 Edition
BIOL 101 Module 4 Exam | Essential Biology I w/Lab | Portage Learning | Q & A | 2026/2027
Edition (PDF)
Directions: Select the best answer for each question. This original study assessment is aligned to Module 4 topics
including the cell cycle, mitosis, meiosis, heredity, inheritance, genetic crosses, genetic disorders, and cell-cycle
dysregulation.
1. A diploid somatic cell contains 12 chromosomes. How many chromosomes should each daughter
cell contain after a normal mitotic division?
A) 12
B) 24
C) 48
D) 6
Correct Answer: A) 12
Rationale: Mitosis preserves chromosome number. After DNA replication, sister chromatids separate so that
each daughter cell receives one complete copy of every chromosome, restoring the original diploid count of 12
rather than halving or doubling it.
2. A cell enters mitosis with replicated chromosomes. What holds the two sister chromatids together
most directly before their separation?
A) Ribosomes
B) Lysosomes
C) Cohesin proteins
D) Gap junctions
Correct Answer: C) Cohesin proteins
Rationale: Cohesin complexes physically link sister chromatids after DNA replication. Their regulated removal
allows chromatids to separate at anaphase. Ribosomes synthesize proteins, lysosomes digest cellular material,
and gap junctions mediate communication between adjacent animal cells.
3. Which event defines metaphase of mitosis?
A) Nuclear envelopes reform
B) DNA replication begins
C) Chromosomes align at the metaphase plate
D) Homologous chromosomes pair
BIOL 101 Module 4 Practice Examination | 2026/2027 Edition Page 1
, Correct Answer: C) Chromosomes align at the metaphase plate
Rationale: In metaphase, duplicated chromosomes align at the cell equator with sister kinetochores attached to
opposite spindle poles. Nuclear-envelope reformation occurs in telophase, homologous pairing is characteristic of
meiotic prophase I, and DNA replication precedes mitosis.
4. At the end of mitotic anaphase, what has happened to sister chromatids?
A) They have decondensed completely
B) They have paired with homologs
C) They have separated and moved toward opposite poles
D) They have replicated again
Correct Answer: C) They have separated and moved toward opposite poles
Rationale: Anaphase begins when sister chromatid cohesion is released, allowing spindle forces to move the
chromatids toward opposite poles. Homolog pairing is meiotic, DNA replication occurs before mitosis, and full
chromosome decondensation is associated with telophase.
5. Loss of a functional tumor-suppressor protein is most likely to have which effect?
A) Reduced restraint on cell-cycle progression
B) Guaranteed activation of meiosis
C) Permanent prevention of mutation
D) Immediate chromosome replication arrest in all cells
Correct Answer: A) Reduced restraint on cell-cycle progression
Rationale: Tumor-suppressor proteins normally restrain proliferation, promote repair, or trigger cell death when
damage is severe. Loss of that restraint can permit abnormal cell-cycle progression. It does not automatically
initiate meiosis or guarantee either replication arrest or mutation prevention.
6. In animal cells, the contractile ring that drives cytokinesis is composed primarily of which
cytoskeletal components?
A) Keratin and laminin
B) Tubulin and dynein only
C) Collagen and elastin
D) Actin and myosin
Correct Answer: D) Actin and myosin
Rationale: Animal-cell cytokinesis is driven by an actin-myosin contractile ring that constricts the plasma
membrane to form a cleavage furrow. Tubulin is central to the spindle, while collagen, elastin, keratin, and laminin
are not the primary machinery of the contractile ring.
7. What is the principal purpose of chromosome condensation during mitosis?
A) To translate more proteins
B) To facilitate safe and efficient chromosome movement
C) To dissolve spindle fibers
D) To increase the amount of DNA
BIOL 101 Module 4 Practice Examination | 2026/2027 Edition Page 2
