Meiosis

4.2.1 State that meiosis is a reduction division of a diploid nucleus to form haploid nuclei.

4.2.2 Define //homologous chromosomes //.

4.2.3 Outline the process of meiosis, including pairing of homologous chromosomes and crossing over, followed by two divisions, which results in four haploid cells.

4.2.4 Explain that non-disjunction can lead to changes in chromosome number, illustrated by reference to Down syndrome (trisomy 21).

4.2.5 State that, in karyotyping, chromosomes are arranged in pairs according to their size and structure.

4.2.6 State that karyotyping is performed using cells collected by chorionic villus sampling or amniocentesis, for pre-natal diagnosis of chromosome abnormalities.

4.2.7 Analyse a human karyotype to determine gender and whether non-disjunction has occurred.