{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

mitosis and meiosis - Lecture notes Mitosis cell division...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Lecture notes 9/16/09 Mitosis cell division in somatic cells original cells produce 2 identical daughter cells growth repair/replacement of tissue Steps in Mitosis 46 double stranded chromosomes line up at the center of the cell chromosome pairs split and move to opposite ends of the cell cell membrane pinches in and 2 new cells are formed Meiosis gamete production 2 divisions result in 4 haploid gametes Recombination (crossing over) the exchange of genetic material between homologous chromosomes during meiosis Evolutionary significance of meiosis natural selection acts on variation meiosis creates new genetic variation shuffling of chromosomes recombination (crossing over) creates new chromosomes Problems with meiosis Non-disjunction-the failure of homologous chromosomes or chromosome strands to separate during cell division. (trisomy and monosomy) Down syndrome (Trisomy 21) 1/800 to 1/1000 births affects mental development, wide skull, epicantheric fold, heart defects
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}