Bio3400 Chapter 2 Mitosis and Meiosis
  1. In prokaryotes such as Escherichia coli, the genetic material      is organized as a long circular molecule located in a           area.

  2. In eukaryotes, DNA is transmitted from one generation of cells to the next by mitosis, which produces diploid          cells, and meiosis, which produces haploid          or spores.

  3. Fusion of two gametes at fertilization results in a diploid         .
  4. In somatic cells, chromosomes exist in             pairs. Such cells are          (2n) and contain two copies, or          , of each gene.

  5. Somatic cells undergo a cell        : an actively dividing stage called          alternates with an             .

  6. In             the cell may become nondividing or engage in duplication of      , organelles, and other cell components in preparation for the next division.
  7. Mitosis consists of          division (karyokinesis), which can be broken into five discrete stages, followed by              division (cytokinesis).
    • In           , the centrioles divide and move apart, the nuclear envelope breaks down, and the chromatin condense and become visible              .

    • In               , the chromosomes move to the equatorial plane of the cell.

    • In            , the chromosomes are aligned at the equatorial plane.

    • In           , sister chromatids separate from each other and migrate to opposite poles.

    • In            , the separated daughter              complete migration to opposite poles of the cell, and              divides the cell in two.

  8. Mitosis produces two diploid daughter cells that are genetically identical. Mitosis review.
  9. Meiosis produces haploid          and requires two rounds of cell division.
    • Meiosis I is the chromosome            division and produces two          cells with two             still attached to the chromosomes.

    • Meiosis II is an             division and each cell from Meiosis I produces two more          cells each with one            .

    Meiosis review and comparison with mitosis.

  10. Sexual reproduction produces genetic            by several mechanisms.
    • In independent             , each pair of chromosomes sorts its             into daughter cells independently, giving 223 (about        million) combinations in humans.
    • The random fusion of gametes during                produces a zygote with 223 x 223, or over     trillion, combinations of chromosomes.
    • Crossing over produces              chromosomes that carry genes derived from different parents, increasing genetic variation even more.
  11. In animals, sexual reproduction involves the                of haploid          to produce diploid reproductive individuals.
    • Male gametes are produced by                  in the         .

    • Female gametes are produced by            in the        .

  12. In plants, sexual reproduction alternates between a multicellular diploid             generation with a multicellular haploid              generation.