Transcript mitosis notes

Cell Reproduction and
Growth
Pages 207 - 216
Limits on Cell Size
• Diffusion is more efficient over short distances
• DNA limitations (has to be able to make proteins
for whole cell)
• Surface area – to – volume ratio
Cell Reproduction
• 1 somatic cell (parent cell) reproduces to make
2 identical somatic cells (daughter cells)…
The Cell Cycle
(phases in the life cycle of a cell)
Interphase (G1, S, G2)
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
What happens in each of
these phases of the cell
cycle?
Interphase
• Cell grows in size and metabolizes
• Chromosomes duplicated
•G1-growth phase 1
•S-synthesis
•G2-growth phase 2
1. Prophase
• Chromatin coils up into chromosomes
(Chromosomes are made up of 2 sister chromatids
attached by a centromere)
• Nucleus disappears
• Centrioles move to poles
• Spindle forms
2. Metaphase
• Chromosomes attach to the spindle
and line up on the equator of the cell.
• Spindle fibers attach to each sister
chromatid at the centromere.
3. Anaphase
• Sister chromatids separate and move
to opposite poles as spindle fibers
shorten
4. Telophase
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Chromatids reach poles
Chromosomes unwind
Nuclei reform
Spindle fibers break down
5. Cytokinesis
• Division of the cytoplasm…separation
of the 2 new cells
Cytokinesis:
Animal vs.
Plant
• Plasma membrane
pinches in (cleavage
furrow)
• Cell is pinched in
two
• Cell plate laid down
along equator
• Plasma membrane
forms around each
cell
• New cell walls form
on each side of cell
plate
Summary
Mitosis
Check your BRAIN!
1.
Describe how a cell’s surface area-tovolume ratio limits its size.
2. Why is it necessary for a cell’s
chromosomes to be distributed to its
daughter cells in such a precise manner?
3. How is the division of cytoplasm different
in plants and in animals?
4. List the 5 phases of mitosis.
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Key Terms
Chromosomes
Chromatin
Sister chromatids
Centromere
Spindle (spindle fibers)
Centrioles
Cleavage furrow
Cell plate
Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis