MitosisWhat is it?Why is it Important?

What do I need to know?

What is Mitosis?MITOSIS: division of the nucleus into two identical daughter cells

http://fairmanstudios.com/als.htm

Why is mitosis important? Eukaryotes use

cell division to create new cells

Growth, Maintenance and Repair of body cells

Asexual cell division

What makes up the cell cycle?

MITOSIS isaboutorganizing anddistributing

CHROMOSOMES

≠ Chromosome made of a DNA and protein complex: chromatinFollowing DNA replication, a chromosome contains two sister chromatids attached by a centromere

Sister

Chromatids

Centromere

Chromosome

What happens in INTERPHASE? Cells are in interphase

90% of the time G1 = Gap 1 (cell

growth) S =chromosome

synthesis (duplication) G2 = Gap 2 (cell

growth) M = Mitosis

INTERPHASE:

nuclear envelope

clearly visible

chromatin, NOchromosomes,yet

nucleolus (if any) still visible

PROPHASE

PROPHASE

chromosomesbecome visible

nuclear envelopedisappears

nucleolusdisappears

PROPHASE

Centrioles migrate & form spindle.

Centrioles

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?