Transcript Mitosis and Meiosis

Mitosis and Meiosis
Year 10 Biology
Mitosis and Meiosis
• Mitosis:
-division of somatic (body) cells
• Meiosis
-division of gametes (sex cells –
sperm and eggs)
Mitosis
• 2 identical daughter cells produced
• Each daughter cell has the same
number of chromosomes as the
parent cell
• 1 set of cell division involved
• End result – 2 diploid (or 2n) cells
with 46 chromosomes in each
Mitosis
• Interphase
• Prophase
• Metaphase
• Anaphase
• Telophase
Interphase
• Interesting things happen!
1. Cell preparing to divide
2. Genetic material doubles (46 to 92)
Prophase
•
1.
Chromosome pair up!
Chromosomes thicken and shorten
-become visible
-2 chromatids joined by a centromere
2. Nuclear membrane disintegrate
3. Spindle fibres form
Metaphase
• Chromosomes meet in the middle!
1. Chromosomes arrange at equator of
cell
2. Become attached to spindle fibres
by centromeres
Anaphase
• Chromosomes get pulled apart
1. Spindle fibres contract pulling
chromatids to the opposite poles of
the cell
Telophase
•
1.
2.
3.
4.
Now there are two!
Chromosomes uncoil
Spindle fibres disintegrate
Nucleur membrane forms
Cell divides
Meiosis
• 4 daughter cells produced
• Each daughter cell has half the
chromosomes of the parent (halpoid
or ‘n’)
• 2 sets of cell division involved
• End result – 4 cells with 23
chromosomes in each
Meiosis
• Interphase
Prophase II
• Prophase
Metaphase II
• Metaphase
Anaphase II
• Anaphase
Telophase II
• Telophase