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Cell Reproduction

Cell Reproduction. Chromosomes: made of DNA. DNA : stores all genetic information. - genes: a hereditary unit of DNA -4 bases: -Adenine -Thymine -Guanine -cytosine. DNA in the Cell. Chromosome Supercoil Subcoil One coil DNA with histine protein DNA. Chromosome Anatomy.

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Cell Reproduction

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  1. Cell Reproduction

  2. Chromosomes: made of DNA

  3. DNA: stores all genetic information -genes:a hereditary unit of DNA -4 bases: -Adenine -Thymine -Guanine -cytosine

  4. DNA in the Cell • Chromosome • Supercoil • Subcoil • One coil • DNA with histine protein • DNA

  5. Chromosome Anatomy

  6. Chromosome Types • Sex Chromosomes: determines the sex of an organism -XY: male -XX: female • Autosomes: All other chromosomes of an organism

  7. Chromosome Duplication

  8. Homologous Chromosomes: two copies of each autosome – same size, shape, and genes

  9. Karyotype: photomicrograph of chromosomes Humans have 22 pairs of autosomes and 1 pair of sex chromosomes

  10. Diploid Cells (2n): cells with both sets of chromosomes (both homologous pairs) 46 chromosomes/23 pairs in humans

  11. Haploid cells (1n): cells with one set of chromosomes

  12. “C” words of Cytology 1. Chromosome: condensed genetic material • Chromatid: one of two identical copies of DNA • Centromere: region that joins the chromatids

  13. “C” words of Cytology • Centrioles: cylindrical structures that assist in cell division • Centrosome: dark regions in the cytoplasm that create spindle fibers

  14. Cell Division: all cells come from pre-existing cells

  15. 2 Types of Division

  16. 1. Mitosis: cell division which produces 2 diploid, identical cells

  17. 2. Meiosis: cell division which produces 4 haploid cells

  18. Cell Life Cycle Interphase: G1, S, and G2 G = growth S = Synthesis M phase: mitosis – nuclear division Cytokinesis: cytoplasm division

  19. Interphase 1. Interphase: DNA not visible -nucleus still intact

  20. Phases of Mitosis • Prophase: chromosomes become visible -nucleus disintegrates

  21. Phases of Mitosis • Metaphase: chromosomes connect at the centromere to spindle fibers -line up at the equatorial plate

  22. Phases of Mitosis • Anaphase: spindle fibers recede -pull chromosomes apart -chromosomes retreat to opposite ends

  23. Phases of Mitosis • Telophase: nucleus reforms Cytokinesis splitting the cell -2 daughter cells are formed

  24. 21 22 23 24

  25. Meiosis: cell division which produces 4 haploid cells

  26. Haploid: a cell with half the number of chromosomes (1n)

  27. Fertilization: the fusion of two gametes (sperm/eggs)

  28. Review terms:

  29. Karyotype

  30. Homologous Chromosomes: same chromosomes – one from each parent

  31. Chromatid: one of two identical copies of the same DNA

  32. Meiosis Meiosis -produces four offspring cells of 1n -two cell division cycles (meiosis I & 2) -produces gametes -chromosomes cross over

  33. 8 Stages of Meiosis Prophase I Metaphase I Anaphase I Telophase I Prophase II Metaphase II Anaphase II Telophase II Meiosis I Meiosis II

  34. Prophase I -Tetrads form

  35. Metaphase I -Crossing over: exchange of genetic info between homologous chromosomes

  36. Anaphase I -tetrads are pulled apart

  37. Telophase I -cytokinesis occurs

  38. Prophase II

  39. Metphase II

  40. Anaphase II

  41. Telophase II

  42. Spermatogenesis: meiosis that produces sperm Produces 4 fertile cells; in humans @ 400 billion

  43. Oogenesis: meiosis that produces egg cells Produces 1 fertile cell; about 400 in a lifetime

  44. Types of Reproduction • Sexual reproduction: offspring are the result of combination of parental genetics • Asexual reproduction: no exchange of genetic information – genetically identical to parent

  45. Nature protects the female

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