Meiosis & Sexual Reproduction — Drills · Grade 10 Science

Chapter: Cell Division, Reproduction & Development

What these drills covers

By the end of Meiosis & Sexual Reproduction you should be able to:

6 questions, multiple choice, numeric and written answer, each with a worked explanation.

Vocabulary used: meiosis, gamete, diploid, haploid, homologous chromosomes, crossing over, fertilization, ploidy, nondisjunction.

Problem 1

Meiosis produces
  1. two diploid cells
  2. four haploid cells
  3. two haploid cells
  4. four diploid cells
Answer and explanation

four haploid cells

Two successive divisions produce four cells, each with half the parent's chromosome number.

Problem 2

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

23

Meiosis halves the number, so a gamete carries 23 — one from each homologous pair.

Problem 3

An organism has 4 pairs of homologous chromosomes. How many different gamete chromosome combinations can independent assortment alone produce?
Answer and explanation

16

Each pair separates independently, giving 2⁴ = 16 combinations, before crossing over adds further variation.

Problem 4

Crossing over occurs between
  1. two identical copies of one chromosome
  2. homologous chromosomes paired during meiosis
  3. chromosomes and ribosomes
  4. gametes after fertilization
Answer and explanation

homologous chromosomes paired during meiosis

Paired homologous chromosomes exchange corresponding segments, producing chromosomes with new combinations of alleles.

Problem 5

A cell with 12 chromosomes completes meiosis I. How many chromosomes are in each resulting cell?
Answer and explanation

6

Meiosis I separates homologous pairs, so each cell receives one member of each pair: 12 / 2 = 6.

Problem 6

Explain why sexual reproduction produces more variation among offspring than asexual reproduction, naming two sources of that variation.
Answer and explanation

Asexual reproduction copies one parent's genome, so offspring differ only through mutation. Sexual reproduction combines chromosomes from two parents and shuffles them twice before that: independent assortment distributes each homologous pair into gametes independently, and crossing over exchanges segments between paired chromosomes, creating combinations neither parent had. Fertilization then pairs one of many possible gametes with another, multiplying the possibilities.

Response criteria

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

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