Both are ways a cell divides its nucleus. The difference is the purpose: mitosis copies a cell exactly, meiosis makes gametes with half the chromosomes and a shuffled combination of genes. Everything in the table follows from that.
The comparison table
| Feature | Mitosis | Meiosis |
|---|---|---|
| Purpose | Growth, repair, asexual reproduction | Formation of gametes (sexual reproduction) |
| Where | Somatic (body) cells | Germ cells (testes, ovaries, anthers, ovules) |
| Number of divisions | One | Two (meiosis I and meiosis II) |
| Daughter cells | Two | Four |
| Chromosome number | Same as parent (2n → 2n) | Halved (2n → n) |
| Genetic makeup | Identical to parent | Different from parent and from each other |
| Pairing of homologous chromosomes | No | Yes, in prophase I (synapsis) |
| Crossing over | No | Yes, in prophase I |
| Duration of prophase | Short | Long (prophase I has five sub-stages) |
| Occurs in | All eukaryotes | Sexually reproducing organisms |
Mitosis in one paragraph
A cell that has copied its DNA in S phase enters mitosis: prophase (chromosomes condense, spindle forms), metaphase (chromosomes line up at the equator), anaphase (sister chromatids pulled to opposite poles), telophase (two nuclei re-form), then cytokinesis splits the cytoplasm. Result: two cells with exactly the parent's 46 chromosomes (in humans). Your skin, your gut lining, a healing cut — all mitosis.
Meiosis in one paragraph
Meiosis is two divisions after a single DNA replication. Meiosis I separates homologous pairs — this is the reduction division, 2n → n — and before that separation, in prophase I, homologues pair up and exchange segments (crossing over), which is where new gene combinations come from. Meiosis II looks like mitosis: it separates sister chromatids. Four haploid cells result, no two alike. In humans that is sperm and eggs with 23 chromosomes each, so that fertilisation restores 46.
Why the difference matters
- Constant chromosome number. If gametes were made by mitosis, every generation would double its chromosomes. Meiosis halves; fertilisation restores.
- Variation. Crossing over and the random way homologues line up in metaphase I mean siblings differ. That variation is the raw material of evolution.
- Errors. Non-disjunction in meiosis (a pair failing to separate) leads to gametes with an extra or missing chromosome — the basis of Down syndrome (trisomy 21).
How examiners ask it
- "Give three differences between mitosis and meiosis." — Pick number of divisions, daughter cells, chromosome number. Write them as a two-column table; one-word answers score.
- "Why is meiosis called reduction division?" — Because the chromosome number is halved in meiosis I.
- "Name the stage where crossing over occurs." — Pachytene of prophase I.
- "A cell with 24 chromosomes undergoes meiosis. How many chromosomes in each gamete?" — 12.
- NEET favourite: the difference between anaphase I (homologues separate, centromeres intact) and anaphase II (sister chromatids separate, centromeres split).
A memory hook
Mitosis makes mirror images. Meiosis makes mess — in the good sense: different cells, half the chromosomes, and it takes two goes to do it.