16 Mitosis and Meiosis key p. 139

Plant mitosis and interphase in Allium (onion) root-tip cells

Calculations to determine stage length:
See p. 135: typical plant cell cycle is about 800 (not 80) minutes.
If interphase comprises 80% of cells: 800 min. * .8 = 640 min. = 10 hours, 40 min.

Rank the stages from longest to shortest:
Interphase usually longest, followed by prophase and telophase; metaphase/anaphase usually shortest.

Animal mitosis and interphase in whitefish (Coregonus clupeaformis) blastula cells p. 140


  1. Compare mitosis as it occurs in plant and animal cells. What are the similarities and differences? (See p. 135)
    Plant cells: chromosomes appear bigger, cell plate during cytokinesis.
    Animal cells: centrosomes visible as asters, more distinct microtubules, cleavage furrow during cytokinesis.

  2. In mammals, how is meiosis similar and different between the male and the female? p. 141
    Male: 1 primary spermatocyte produces 4 equal-sized, small sperm.
    Female: 1 primary oocyte produces 1 large ovum (unfertilized egg) + 2/3 polar bodies.

  3. Contrast mitosis and meiosis. How do the processes differ? In what ways are the processes similar? How do the processes differ in function to an organism?
                             mitosis        meiosis
            divisions        1              2
            daughter cells   2 diploid      4 haploid
            function         growth/repair  gametes, genetic variation
    Similarities: DNA replication before first cell division, stages of cell division, cytokinesis.

Lab notes made Jul 12, 2010 by Peter Chen