BIOL180 Unit Test 4 Cell Division,
Mitosis, and Meiosis Questions And
Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
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1. What is the primary purpose of cell division in multicellular
organisms?
A. To eliminate all genetic variation
B. To produce ATP for cellular respiration
C. To allow growth, development, and tissue repair
D. To prevent DNA replication
Answer: C. To allow growth, development, and tissue repair
Rationale: Cell division allows multicellular organisms to increase
their number of cells during growth and development and replace
damaged or aging cells. Mitosis produces genetically similar daughter
cells that maintain the chromosome number of the parent cell. Cell
division is therefore essential for growth, maintenance, and repair.
ATP production is primarily associated with metabolic pathways rather
than being the central purpose of cell division, and DNA replication is
required before division rather than prevented by it.
2. Which sequence correctly represents the major stages of the cell
cycle?
A. G1 → S → G2 → M
B. S → G2 → G1 → M
,C. M → G2 → S → G1
D. G2 → M → S → G1
Answer: A. G1 → S → G2 → M
Rationale: The cell cycle is commonly divided into G1, S, G2, and M
phases. During G1, the cell grows and performs normal functions.
During S phase, DNA is replicated. G2 provides additional growth and
preparation for division. M phase includes mitosis and cytokinesis.
The order is therefore G1, S, G2, and M.
3. During which phase of the cell cycle is DNA replicated?
A. G1 phase
B. S phase
C. G2 phase
D. M phase
Answer: B. S phase
Rationale: The S phase, or synthesis phase, is the portion of interphase
during which the cell duplicates its DNA. Each chromosome is copied
to produce two genetically identical sister chromatids joined at the
centromere. G1 occurs before DNA replication, while G2 occurs after
replication and prepares the cell for division. M phase involves
chromosome separation and cell division rather than DNA synthesis.
4. Which structure holds sister chromatids together before they
separate?
A. Nucleolus
B. Ribosome
C. Lysosome
D. Centromere
Answer: D. Centromere
,Rationale: The centromere is the chromosomal region where sister
chromatids remain associated before their separation. It is also
associated with the kinetochore, a protein structure that interacts with
spindle microtubules. The nucleolus produces ribosomal components,
ribosomes participate in protein synthesis, and lysosomes digest
cellular materials.
5. A chromosome immediately after DNA replication consists of:
A. Two sister chromatids
B. Four homologous chromosomes
C. One chromatid with no DNA
D. Two unrelated chromosomes
Answer: A. Two sister chromatids
Rationale: After DNA replication, each chromosome consists of two
nearly identical DNA molecules called sister chromatids. They remain
attached at the centromere until they separate during cell division.
Replication doubles the amount of DNA but does not immediately
double the chromosome number because the sister chromatids are still
considered part of the same chromosome.
6. Which event occurs during G1 phase?
A. Homologous chromosomes pair
B. Sister chromatids separate
C. Cell growth and normal cellular activity occur
D. Crossing over occurs
Answer: C. Cell growth and normal cellular activity occur
Rationale: During G1, the cell grows, carries out normal metabolic
activities, produces proteins and organelles, and prepares for DNA
synthesis. Homologous chromosome pairing and crossing over occur
, during meiosis I, while sister chromatid separation occurs during
mitosis or meiosis II.
7. What is the main purpose of the G2 checkpoint?
A. To initiate crossing over
B. To verify that DNA replication and cellular preparation are adequate
C. To separate homologous chromosomes
D. To duplicate the chromosome number
Answer: B. To verify that DNA replication and cellular preparation
are adequate
Rationale: The G2 checkpoint helps determine whether DNA
replication has been completed correctly and whether the cell is
sufficiently prepared to enter mitosis. If DNA damage or replication
problems are detected, progression can be delayed while repair occurs.
This checkpoint contributes to genomic stability.
8. Which statement best describes chromatin?
A. It is composed only of RNA
B. It is found exclusively outside the nucleus
C. It exists only during cytokinesis
D. It consists of DNA associated with proteins
Answer: D. It consists of DNA associated with proteins
Rationale: Chromatin is the combination of DNA and associated
proteins, particularly histones, within the nucleus of eukaryotic cells.
When a cell prepares to divide, chromatin becomes more condensed
and forms visible chromosomes. Chromatin organization allows long
DNA molecules to be packaged efficiently while still permitting access
for processes such as transcription and replication.
Mitosis, and Meiosis Questions And
Correct Answers (Verified Answers)
Plus Rationales 2026 Q&A | Instant
Download Pdf
1. What is the primary purpose of cell division in multicellular
organisms?
A. To eliminate all genetic variation
B. To produce ATP for cellular respiration
C. To allow growth, development, and tissue repair
D. To prevent DNA replication
Answer: C. To allow growth, development, and tissue repair
Rationale: Cell division allows multicellular organisms to increase
their number of cells during growth and development and replace
damaged or aging cells. Mitosis produces genetically similar daughter
cells that maintain the chromosome number of the parent cell. Cell
division is therefore essential for growth, maintenance, and repair.
ATP production is primarily associated with metabolic pathways rather
than being the central purpose of cell division, and DNA replication is
required before division rather than prevented by it.
2. Which sequence correctly represents the major stages of the cell
cycle?
A. G1 → S → G2 → M
B. S → G2 → G1 → M
,C. M → G2 → S → G1
D. G2 → M → S → G1
Answer: A. G1 → S → G2 → M
Rationale: The cell cycle is commonly divided into G1, S, G2, and M
phases. During G1, the cell grows and performs normal functions.
During S phase, DNA is replicated. G2 provides additional growth and
preparation for division. M phase includes mitosis and cytokinesis.
The order is therefore G1, S, G2, and M.
3. During which phase of the cell cycle is DNA replicated?
A. G1 phase
B. S phase
C. G2 phase
D. M phase
Answer: B. S phase
Rationale: The S phase, or synthesis phase, is the portion of interphase
during which the cell duplicates its DNA. Each chromosome is copied
to produce two genetically identical sister chromatids joined at the
centromere. G1 occurs before DNA replication, while G2 occurs after
replication and prepares the cell for division. M phase involves
chromosome separation and cell division rather than DNA synthesis.
4. Which structure holds sister chromatids together before they
separate?
A. Nucleolus
B. Ribosome
C. Lysosome
D. Centromere
Answer: D. Centromere
,Rationale: The centromere is the chromosomal region where sister
chromatids remain associated before their separation. It is also
associated with the kinetochore, a protein structure that interacts with
spindle microtubules. The nucleolus produces ribosomal components,
ribosomes participate in protein synthesis, and lysosomes digest
cellular materials.
5. A chromosome immediately after DNA replication consists of:
A. Two sister chromatids
B. Four homologous chromosomes
C. One chromatid with no DNA
D. Two unrelated chromosomes
Answer: A. Two sister chromatids
Rationale: After DNA replication, each chromosome consists of two
nearly identical DNA molecules called sister chromatids. They remain
attached at the centromere until they separate during cell division.
Replication doubles the amount of DNA but does not immediately
double the chromosome number because the sister chromatids are still
considered part of the same chromosome.
6. Which event occurs during G1 phase?
A. Homologous chromosomes pair
B. Sister chromatids separate
C. Cell growth and normal cellular activity occur
D. Crossing over occurs
Answer: C. Cell growth and normal cellular activity occur
Rationale: During G1, the cell grows, carries out normal metabolic
activities, produces proteins and organelles, and prepares for DNA
synthesis. Homologous chromosome pairing and crossing over occur
, during meiosis I, while sister chromatid separation occurs during
mitosis or meiosis II.
7. What is the main purpose of the G2 checkpoint?
A. To initiate crossing over
B. To verify that DNA replication and cellular preparation are adequate
C. To separate homologous chromosomes
D. To duplicate the chromosome number
Answer: B. To verify that DNA replication and cellular preparation
are adequate
Rationale: The G2 checkpoint helps determine whether DNA
replication has been completed correctly and whether the cell is
sufficiently prepared to enter mitosis. If DNA damage or replication
problems are detected, progression can be delayed while repair occurs.
This checkpoint contributes to genomic stability.
8. Which statement best describes chromatin?
A. It is composed only of RNA
B. It is found exclusively outside the nucleus
C. It exists only during cytokinesis
D. It consists of DNA associated with proteins
Answer: D. It consists of DNA associated with proteins
Rationale: Chromatin is the combination of DNA and associated
proteins, particularly histones, within the nucleus of eukaryotic cells.
When a cell prepares to divide, chromatin becomes more condensed
and forms visible chromosomes. Chromatin organization allows long
DNA molecules to be packaged efficiently while still permitting access
for processes such as transcription and replication.
