Mitosis and Cytokinesis

Putting it Together: Mitosis LT5: I can demonstrate the processes that cells go through to divide.

Mitosis Somatic (body) cell division 5 step process Growth Repair 5 step process Outcome: Production of an identical cell (Diploid) Why is mitosis easy to see in specimens such as this root tip?

Interphase Cells spend most of their time here Carrying out life processes Growth Metabolism Protein Production Etc. DNA is replicated

Homologous Chromosomes The Genetic Material The genetic material is packaged in the nucleus of the cell Packaged unit is called a Chromosome Homologous Chromosomes Chromosome

Prophase Chromosomes begin to condense Spindle fibers form Tightly coil Makes it harder to break Spindle fibers form Centromeres form Spindle fibers form

Metaphase Sister chromatids line up at the middle of the cell Mitotic plate Spindle fibers attach to centromeres

Anaphase Spindle fibers shorten Sister chromatids are separated One of each chromosome goes to each side

Telophase Contractile ring begins to form Cells double check to make sure they have correct number of chromosomes Nuclear envelope forms Contractile Ring

Cytokinesis Division of cytoplasm and cell organelles

Review

Putting it Together: Meiosis LT5: I can differentiate between the division of somatic cells and sex cells

Meiosis Sex cell division 2 step process Gamete formation i.e. Sperm and Egg 2 step process Meiosis I and II Outcome: Production sex cells (haploid)

Meiosis I

Homologous Chromosomes Tetrads form Chromosomes with same sequence of genes Pair and exchange segments of DNA Ensures genetic diversity (survival) Called a tetrad (4) 15

Meiosis II

The Results

Quick Write Identify as many differences between meiosis and mitosis as you can in 1 min.

For Extra Help For more help: http://www.phschool.com/science/biology_place/labbench/lab3/intro.html For more help: http://www.pbs.org/wgbh/nova/body/how-cells-divide.html