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?