Cell Division, Reproduction & Development — Chapter quiz · Life Science: Biology, Grade 10

Connect chromosome continuity, variation, regulated growth, and specialization.

Problem 1

Which is the correct order of the phases of mitosis?
  1. Metaphase, Prophase, Telophase, Anaphase
  2. Telophase, Anaphase, Metaphase, Prophase
  3. Anaphase, Prophase, Metaphase, Telophase
  4. Prophase, Metaphase, Anaphase, Telophase
Answer and explanation

Prophase, Metaphase, Anaphase, Telophase

The phases run Prophase, Metaphase, Anaphase, Telophase — remembered as PMAT.

Problem 2

Starting from a single cell, how many cells result after 4 rounds of mitosis?
Answer and explanation

16 cells

Each round doubles the count: 2^4 = 16 cells.

Problem 3

A human body cell has 46 chromosomes. How many chromosomes are in a human sperm or egg cell?
Answer and explanation

23 chromosomes

Gametes are haploid, carrying half the diploid number: 46 / 2 = 23.

Problem 4

Crossing over during meiosis increases genetic variation by
  1. exchanging matching segments between homologous chromosomes
  2. copying the whole cell exactly
  3. removing half of the organism's genes
  4. building new proteins at the ribosome
Answer and explanation

exchanging matching segments between homologous chromosomes

Homologous chromosomes swap segments, producing chromosomes with new combinations of alleles.

Problem 5

A cell is observed with chromosomes aligned along the centre of the cell. This is
  1. prophase
  2. metaphase
  3. telophase
  4. the S phase
Answer and explanation

metaphase

Alignment at the cell's midline is the defining feature of metaphase, immediately before the copies separate in anaphase.

Problem 6

Explain why DNA replication must precede chromosome separation, and what would result if a cell entered mitosis with replication incomplete.
Answer and explanation

Separation divides already-duplicated chromosomes between two cells, so each copy must exist before the division occurs. If a cell entered mitosis with replication incomplete, the chromosomes would be divided unevenly: some regions would be present in only one daughter cell and absent from the other, so one cell would lack genes it needs. A checkpoint at the end of interphase normally halts the cycle until replication is finished, which is why its failure is serious.

Response criteria

  • State a biologically accurate conclusion.
  • Show the data, mechanism, or calculation that supports it.
  • Include units, conditions, or limits where relevant.

Problem 7

Independent chapter check: A diploid model starts with 10 chromosomes. Track chromosomes, chromatids and daughter-cell chromosome number through replication and normal mitosis/cytokinesis.
Answer and explanation

After S phase there are 10 replicated chromosomes and 20 chromatids; during separation each former chromatid becomes a chromosome. Each daughter receives 10 chromosomes, preserving diploidy in the model.

After S phase there are 10 replicated chromosomes and 20 chromatids; during separation each former chromatid becomes a chromosome. Each daughter receives 10 chromosomes, preserving diploidy in the model.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the biological mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

Problem 8

The key difference between meiosis I and mitosis is that in meiosis I
  1. chromosomes do not replicate beforehand
  2. homologous pairs separate rather than individual duplicated chromosomes
  3. no cytokinesis occurs
  4. the cell gains chromosomes
Answer and explanation

homologous pairs separate rather than individual duplicated chromosomes

Mitosis separates the two copies of each duplicated chromosome; meiosis I separates the members of each homologous pair, which is what halves the chromosome number.

Problem 9

Explain why an organism's chromosome number stays constant across generations even though two parents each contribute genetic material.
Answer and explanation

Meiosis halves the chromosome number when gametes form, so each gamete carries one member of each homologous pair rather than a full set. Fertilization combines two such gametes, restoring the full number in the zygote. Halving before combining is what keeps the number constant; without meiosis the number would double each generation.

Response criteria

  • State a biologically accurate conclusion.
  • Show the data, mechanism, or calculation that supports it.
  • Include units, conditions, or limits where relevant.

Problem 10

Independent chapter check: A diploid model has 2n=6. Give chromosome and chromatid counts after S phase, after meiosis I per nucleus and after meiosis II per nucleus.
Answer and explanation

After S: 6 chromosomes and 12 chromatids. After I: 3 replicated chromosomes and 6 chromatids per nucleus. After II: 3 unreplicated chromosomes per nucleus. The standard model includes one replication before two divisions.

After S: 6 chromosomes and 12 chromatids. After I: 3 replicated chromosomes and 6 chromatids per nucleus. After II: 3 unreplicated chromosomes per nucleus. The standard model includes one replication before two divisions.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the biological mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

Problem 11

What does differentiation usually change?
  1. Patterns of expression and cell function
  2. The need for all membranes
  3. The identity of every inherited base by design
  4. All cells into identical cells
Answer and explanation

Patterns of expression and cell function

Specialization depends strongly on regulated expression.

Problem 12

Why does a tissue need both division and differentiation?
Answer and explanation

Division supplies cells; differentiation provides the specialized functions and organization needed for the tissue.

Problem 13

Independent chapter check: Two samples share the same DNA sequence at a tested gene but show different RNA amounts and cell functions. Explain a possible mechanism and one limit of the evidence.
Answer and explanation

Different regulation can change expression without changing that tested sequence. Other genes, processing and cellular conditions can contribute; matching one gene does not establish complete genome identity or a unique cause.

Different regulation can change expression without changing that tested sequence. Other genes, processing and cellular conditions can contribute; matching one gene does not establish complete genome identity or a unique cause.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the biological mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

Problem 14

A diploid animal has 32 chromosomes. How many are in a normal gamete?
Answer and explanation

16 chromosomes

32 ÷ 2 = 16.

Problem 15

Why does mitosis alone not explain the formation of several different organs?
Answer and explanation

Differentiation, signals, spatial organization, and interactions produce different tissues and structures.

Problem 16

Independent chapter check: A supplied embryo model divides from 1 to 8 cells while total material is initially comparable. Explain cell number versus size, and how different cell fates could arise without new mutations.
Answer and explanation

Cleavage partitions material among more, smaller cells rather than requiring eightfold growth. Positional signals and gene regulation can change cell fate without new DNA-sequence changes; structure/function evidence must test those outcomes.

Cleavage partitions material among more, smaller cells rather than requiring eightfold growth. Positional signals and gene regulation can change cell fate without new DNA-sequence changes; structure/function evidence must test those outcomes.

Response criteria

  • Use the stated measurements or conditions, with correct units.
  • Connect the result to the biological mechanism or evidence relationship.
  • Identify the assumption, model limit or further evidence requested.

Browse all courses