Unit 5: Heredity

One diploid (2n) cell produces four haploid (n) cells, each with one set of chromosomes; it makes gametes (or spores in plants and fungi).

Fertilization combines two gametes; if each carries one set (n), the zygote restores the diploid number (2n) and chromosome number stays constant across generations.

Homologous chromosomes separate and move to opposite poles; sister chromatids stay joined at their centromeres.

Sister chromatids separate, much like in mitosis, producing single-chromatid chromosomes in each of four haploid cells.

A pair of chromosomes, one from each parent, with the same genes at the same loci and similar size and centromere position, though they may carry different alleles.

4 chromosomes after meiosis I (each still two chromatids) and 4 chromosomes after meiosis II (each a single chromatid).