1. Ch. 8 – Cellular reproduction As a comparative / overview, organisms reproduce sexually and/or asexually asexual reproduction –Offspring are produced by a single parent, without the participation of sperm or the transfer of genetic information sexual reproduction –Transfer and integration of genetic information; i.e. fertilization of sperm and egg produces variety of offspring In regards to Eukaryotic cells – unicellular organisms or cells of multicellular organisms… –asexual reproduction = ? Mitosis –sexual reproduction = ? Meiosis

2. Cellular reproduction or division Asexual reproduction –Genetic copies of single parent cell –“like begets like” –“clones”

3. Prokaryotic asexual cellular division Binary fission Cell divides into two –Asexually relatively simple

4. …as simple as “one, two, three” Cell replicates its genetic material –Single chromosome of DNA Copies move apart Growing membrane divides the cell

5. Eukaryotic cellular division Cells are larger …more complex Have more genes than prokaryotes –Grouped into multiple chromosomes in nucleus before division begins –DNA condenses into thin loosely packed chromatin fibers which bind to histones (proteins) to form chromosomes

6. …before division –Chromosomes replicate into… –Sister chromatids joined at centromere Two genetic copies Eventually divides into two identical chromosomes

8. Cell cycle multiplies cells Most of the cycle is preparing for division –Interphase Growth and replication –Cellular division process starts with mitosis Prophase, Metaphse, Anaphase, Telophase

9. Interphase Cell growth –Doubling most of its contents –Addition of two centrosomes in cytoplasm Contain two centrioles Microtubule organizing centers

10. Prophase of Mitosis Chromatin fibers coil forming discrete chromosomes –Joined at waist –Sister chromatids Mitotic spindle forms –Microtubules extending from centrosomes Centrosomes start to migrate to opposite poles

11. Late Prophase Nuclear membrane breaks down Spindle fibers reach the condensed chromosomes –One end originating at centrosome, other attached to each sister chromatid

13. Metaphase Mitotic spindle fully formed Centrosomes at poles Chromosomes line up at equator

14. Anaphase Centromeres split, separating sister chromatids Attatched spindle fibers shorten Unattached spindle fibers lengthen –Push or elongate cell Copied chromosomes migrate to poles

15. Telophase Reverse of prophase Nuclear membranes begin to form around chromosomes Mitotic spindle disappears Cytoplasm prepares to divide = cytokinesis …two daughter cells

17. http://www.youtube.com/watch?v=VlN7K1-9QB0 http://www.youtube.com/watch?v=eFuCE22agyM

18. Cytokinesis Differs in animals and plants Animal: –Ring of microfilaments contract Pinching the cell Like pulling a purse-string closed

19. Plant cytokinesis Cell wall material forms in center Cell plate extends Cell membrane follows Cell plate fuses with cell walls