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
- Compare mitosis as it occurs in plant and animal cells. What are the similarities and differences? (See p. 135)
chromosomes appear bigger, cell plate during cytokinesis.
centrosomes visible as asters, more distinct microtubules, cleavage furrow during cytokinesis.
- 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.
- 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?
divisions 1 2
daughter cells 2 diploid 4 haploid
function growth/repair gametes, genetic variation
DNA replication before first cell division, stages of cell division, cytokinesis.