meiosis: 10 th grade

Meiosis: 10th Grade

Resources

Are all on the Blog!

Homework for Monday

Create a document which outlines the process of meiosis AND explains one disease that is caused by an error during meiosis• Your document must be accurate, must demonstrate

knowledge, and must be creative• Label AT LEAST: gene; chromosome; DNA, crossing

over and all the steps of meiosis• Provide a summary of ONE disease that results from

an error during meiosis (a non-disjunction disorder)

What is the biological purpose

of sex?

Meiosis is a two step process

• Meiosis 1 separates the homologous pairs of chromosomes: this is the reduction division

• Meiosis 2 separates the sister chromatids (resembles mitosis)

• One single diploid cell produces 4 non-identical haploid cells

Essential definitions: homologous chromosomes

• Human somatic cells have 22 homologous chromosome pairs (autosomes) and one non-homologous pair (sex chromosomes)

• One maternal/ one paternal• Same size and structure• Same genes at same loci• Alleles may differ

Essential definitions: (sister) chromatids

• Chromatid: one of two identical halves (sister chromatids) of a replicated chromosome

• NB: following crossing over, sister chromatids are no longer identical!

Essential definitions: Bivalent (tetrad)

• One pair of homologous (duplicated) chromosomes which associate during prophase 1 of meiosis

• The process of pairing is called synapsis

Getting to grips with meiosis

• Meiosis – the movie• Short summary• Fabulous website based tutorial• Step through from Sumanas

Diploid germ cell chromosomes duplicate during S phase BEFORE meiosis

Homework for Monday

Create a document which outlines the process of meiosis AND explains one disease that is caused by an error during meiosis• Your document must be accurate, must demonstrate

knowledge, and must be creative• Label AT LEAST: gene; chromosome; DNA, crossing

over and all the steps of meiosis• Provide a summary of ONE disease that results from

an error during meiosis (a non-disjunction disorder)