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MitosisWhat is it?Why is it Important?
What do I need to know?
Why more cells? Populations of
single-cell critters Multicellularity? We all start out as
a single cell…? The zygote… & become/remain
multicellular
Binary Fission…Monera
Binary Fission..DNA duplicates…why?
DNA separates & new cell wall divides cell in two
2 ‘new’ cells…identical?
Binary Fission
quiz What happens to the size of bacteria
after binary fission? What has to happen before fission
occurs? What benefit(s) do bacteria derive
from binary fission (as opposed to sexual reproduction)?
Eukaryotic cells?? The nucleus? Nuclear membrane Chromosomes…
not chromosome…?
All that ‘stuff’ in the cytoplasm?
Eukaryotic cell cycle Cell is ‘born’ Duplicates DNA?? Grows to…size? Prepares to divide Divides=mitosis
Control of mitosis:CYCLIN
The nuclelus must first divide before the cell can
Why? How? How much time of
the cell cycle/life can be spent in mitosis?
Chromosomes duplicate
Kinetochore (centromere)
Mitosis produces identical offspring (2N---2N)
Why some cells stop mitosis…differentiation
Muscle cells… Nerve cells… Critical functions
might be disrupted Adaptations to this
condition
Importance??? Growth Replacement Cancer Regeneration of…
Cancer? Unregulated
mitosis Benign Malignant/
metastasis How does it begin?
Normal cycle controls Internal signals External signals:
growth factorsfibronectin,etccarcinogens
Apoptosis Immune functions And…
Cell immortilization!! Hayflick limit?? Hela cells Contact inhibition Increased
telomerase activity = immortalization!
Immortalization??? If you replaced… Why not??…look at
your shoestrings? Telomerase &
telomeres & …? Recently… Implications???
Mitosis quiz Use two words to describe the
importance of mitosis Draw and label the cell cycle…
include G1, S, G2, M and cytokinesis…what happens at each stage?
Why might telomerase be important? What disease is associated with
mitosis? Are all organisms limited to 50 mitotic
divisions?
Name stage of mitosis
Name stage of mitosis
Name stage of mitosis
Name stage of mitosis
Name stage of mitosis
Name stage of mitosis
Name stage of mitosis
Name stage of mitosis
These are bacteria Watch the clip What kind of
reproduction is shown here?
What advantage does this confer on the organism?