IGCSE · Practice questions · Meiosis

Half the set, new combinations.

Six original Cambridge-style questions on where meiosis happens, chromosome numbers in gametes and zygotes, and the differences between mitosis and meiosis.

Original questions All questions on this page are original work, written in the Cambridge IGCSE style. They are not from past papers. They test the same concepts and skills the syllabus rewards.

Keep these straight

Gametes come from meiosis.

Meiosis is involved in producing gametes (sperm, eggs, pollen nuclei).
Extended: reduction division, diploid → haploid (46 → 23 in humans).
Extended: the gametes are genetically different; mitosis gives identical cells.
Fertilisation restores the diploid number: haploid + haploid = diploid zygote.

Recall

[2 marks]

State where meiosis happens in a human male and in a flowering plant.

In the testes (where sperm are made). ✓
In the anthers (to make pollen) and in the ovules (to make egg cells). ✓

Recall

[3 marks]

Extended. Describe what is meant by a reduction division, using the terms diploid and haploid.

A nuclear division (meiosis) in which the chromosome number is halved. ✓
From diploid, two sets of chromosomes (46 in humans), ✓
to haploid, a single set of chromosomes (23 in humans). ✓

Analysis

[4 marks]

Extended. Give four differences between mitosis and meiosis.

Mitosis gives genetically identical cells; meiosis gives genetically different cells. ✓
Mitosis keeps the chromosome number the same; meiosis halves it (diploid to haploid). ✓
Mitosis is used for growth, repair, replacement and asexual reproduction; meiosis is used to make gametes. ✓
Mitosis gives two cells from each division; meiosis gives four cells from one parent cell. ✓

Calculation

[3 marks]

Extended. A species of fruit fly has 8 chromosomes in each body cell. State the number of chromosomes in (a) a sperm cell, (b) a zygote, (c) a cell in the gut lining after mitosis.

(a) 4 (haploid, 8 ÷ 2). ✓
(b) 8 (diploid: a 4-chromosome sperm fuses with a 4-chromosome egg). ✓
(c) 8 (mitosis keeps the chromosome number the same). ✓

Explain

[3 marks]

Extended. Explain why gametes need to be haploid.

At fertilisation two gametes fuse to form a zygote. ✓
If gametes are haploid, the zygote has two sets of chromosomes, so it is diploid (46 in humans). ✓
So the chromosome number stays the same in every generation instead of doubling. ✓

Explain

[2 marks]

Extended. Brothers and sisters with the same parents are not genetically identical (unless they are identical twins). Use your knowledge of meiosis to explain why.

Meiosis produces gametes that are genetically different from each other. ✓
Each child develops from a different egg and a different sperm, fused at random, so each child has a different combination of alleles. ✓

Mark this once you have attempted all six and checked your working. It records a Practiced badge on the topic and adds a one-time bonus. Revealing the solutions alone does not count.