The Cell CycleThe Cell Cycle

The cell cycle. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com)

InterphaseInterphase

Not a part of cell division – consists of 3 stages:

-G1 (first growth stage) addition of biomass and size-S (synthesis) DNA replication-G2 (second growth stage) reproduction/manufacture of

enough organelles for 2 cells

MitosisMitosis

MitosisMitosis

The events of Prophase. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission.

ProphaseProphase

The events of Prophase. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com), used with permission.

Metaphase and AnaphaseMetaphase and Anaphase

The events of Metaphase and Anaphase. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com),

TelophaseTelophase

The events of Telophase. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com)

Results of each…Results of each…

Mitosis:2 genetically identical daughter cells that are

diploid (with pairs of chromosomes)

Meiosis:4 genetically diverse daughter cells that are

haploid (with half of each chromosome pair)

MeiosisMeiosis

Chromosomes Arranged in a Chromosomes Arranged in a KaryotypeKaryotype

Image from Access Excellence Graphics Gallery http://www.accessexcellence.com/AB/GG/mitosis.html

Chromosome Structure as related to Chromosome Structure as related to MeiosisMeiosis

Structure of a eukaryotic chromosome. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com)

Structure and main features of a spindle apparatus. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com)

Sister chromatids = copies of the chromosomes (DNA wound around proteins)

Meiosis 1Meiosis 1

Major events in Prophase I. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com)

Meiosis 1Meiosis 1

Events in prophase and metaphse I. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com)

The events of Telophase I. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com)

Meiosis 2Meiosis 2

The events of Prophase II. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com)

The events of Metaphase II and Anaphase II. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com),

Meiosis 2Meiosis 2

The events of Telophase II. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com)

Sources of VariationSources of VariationCrossing overCrossing over

Independent assortment of chromosomesIndependent assortment of chromosomesSegregation of allele pairs (genes)Segregation of allele pairs (genes)

Crossing-over between homologous chromosomes produces chromosomes with new associations of genes and alleles. Image from Purves et al., Life: The Science of Biology, 4th Edition, by Sinauer Associates (www.sinauer.com) and WH Freeman (www.whfreeman.com)

Image from Access Excellence Graphic Gallery http://www.accessexcellence.com/AB/GG/comparison.html

Comparison of Mitosis Comparison of Mitosis and Meiosisand Meiosis