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Biology 1

Biology 1. Cell Cycle. Cell Review. Cell Theory:. * All living things composed of cells. * Cells are the basic units of structure and function in living things. * New cells are produced from existing cells. Cell Review. Nucleus of the Cell:

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Biology 1

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  1. Biology 1 Cell Cycle

  2. Cell Review Cell Theory: * All living things composed of cells * Cells are the basic units of structure and function in living things. * New cells are produced from existing cells

  3. Cell Review Nucleus of the Cell: Controls most cell processes and contains the hereditary information. This is found as Deoxyribonucleic Acid (DNA) DNA: Coded instructions for making proteins. Chromatin: DNA bound to protein – granular and visible in the nucleus. Chromosomes: Chromatin that condenses in preparation for cell division.

  4. Cell Review Microtubules: They aide in cell division, separating chromosomes (known as centriolesin animal cells).

  5. Cell Division PROKARYOTE CELL DIVISION Eukaryote cell division Asexual Reproduction Growth and replacement of old and/or dying cells Cell Division called Binary Fission Cell Division called the Cell Cycle DNA = One Circular Chromosome and Plasmids DNA = 10-50 chromosomes per cell Humans = 46 (23 identical pairs)

  6. Cell Replication Cell Cycle: Phase 1: Interphase • G1 - primary growth phase • S – synthesis; DNA replicated • G2 - secondary growth phase Phase 2: Mitosis Phase 3: Cytokinesis

  7. Cell Replication (Cell Cycle) Phase 1: Interphase • G1 - primary growth phase • S – synthesis; DNA replicated • G2 - secondary growth phase Cell Matures: Growth and Organelles DNA copied/replicated Cell Structures needed for division made Centrioles

  8. Mitosis: Prophase • Chromatin condenses into chromosomes • Mitotic spindle forms and attaches to centromeres • Nuclear membrane/nucleolus broken down.

  9. Mitosis: Prophase Centrioles dissolving

  10. Mitosis: Metaphase • Chromosomes line up at the equator of the cell

  11. Mitosis: Metaphase Centriole Equator Centromere Centriole

  12. Mitosis: Anaphase • Sister Chromatids pulled apart to opposite poles of the cell.

  13. Anaphase Equator

  14. Review

  15. Mitosis: Telophase • Sister Chromatids completely at opposite poles • Nuclear envelope forms • Nucleolus appears • Cytokinesis occurs

  16. Mitosis: Telophase Equator

  17. Cell Replication (Cell Cycle) Phase 3: Cytokinesis Division of cell into two – Division of the cytoplasm by a cleavage furrow Cleavage Furrow

  18. Cell Cycle Drawing Draw and Label the Following: • Interphase • Nuclear Membrane • Chromatin • Prophase • Centrioles • Nuclear Membrane • (disappearing) • Chromosomes • Metaphase • Centrioles • Chromosomes • Mitotic spindle • Anaphase • Centrioles • Chromosomes • Mitotic spindle • Telophase/Cytokinesis • Chromosomes returning • to chromatin • Nuclear Envelope forming • Cleavage Furrow

  19. What Phase?

  20. What phase?

  21. Name the Stages of Mitosis: Early Anaphase Metaphase Early prophase Interphase Early Telophase, Begin cytokinesis Late Prophase Late telophase, Advanced cytokinesis Mid-Prophase Late Anaphase

  22. http://www.youtube.com/watch?v=ZEwddr9ho-4&feature=related

  23. Cell Chromosomes Karyotype • A picture of the chromosomes from a human cell arranged in pairs by size • First 22 pairs are called autosomes • Last pair are the sex chromosomes • XX female or XY male

  24. Boy or Girl? The Y Chromosome Decides Y - Chromosome X - Chromosome

  25. Meiosis – Formation of Gametes (Eggs and Sperm) Males: Spermatogenesis (formation of sperm) Females: Oogenesis (formation of eggs) Two Stages: Meiosis I and Meiosis II During Meiosis I – Homologs form Tetrads and crossing over occurs, all resulting cells are still diploid (2N) 46 chromosomes During Meiosis II – Chromosomes are split and all cells become haploid (1N) 23 chromosomes Entire process called reduction division Why is this important?

  26. Homologs form Tetrads Homologous chromosomes(compare to sister chromatids) Join to form a tetrad Called Synapsis (compare to a centromere)

  27. Crossing-Over • Homologous chromosomes in a tetrad cross over each other • Pieces of chromosomes or genes are exchanged • Produces Genetic recombination in the offspring

  28. Crossing-Over Crossing-over multiplies the already huge number of different gamete types

  29. Cell Cycle and Meiosis Lets compare Mitosis and Meiosis – What do you know?

  30. 46 chromatids (92 chromosomes, paired after replication – held by a synapsis/centromere) 46 chromosomes each side Mitosis: 46 chromosomes Meiosis: 23 chromosomes

  31. Comparison of Divisions

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