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Understanding Cell Reproduction and Chromosome Anatomy

This overview explores the intricate processes of cell reproduction, focusing on chromosome anatomy, types, and functions in the cell cycle. It covers DNA's role as the fundamental carrier of genetic information, the distinction between diploid and haploid cells, and highlights key reproductive processes such as mitosis and meiosis. Learn about chromosome types, including autosomes and sex chromosomes, and the significance of karyotype analysis. The mechanisms of genetic diversity through crossover in meiosis and the basics of sexual and asexual reproduction are also discussed.

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Understanding Cell Reproduction and Chromosome Anatomy

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Presentation Transcript

  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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