Stages of Mitosis

Mitosis (M Phase)

The M Phase consists of:• Mitosis and Cytokinesis

Four Stages of Mitosis:Prophase MetaphaseAnaphaseTelophase

Late InterphaseCentrosome (with centriole pair)

Nuclear membrane

Nucleolus

Chromatin

Late Interphase

• Cell is preparing for division.

• Chromatin (relaxed form of DNA) has been replicated.

• Nuclear membrane and nucleolus are still visible.

Early & Late ProphaseSpindle apparatus

Centromere (where sister chromatids attach)

Nuclear membrane (disappearing)

Chromosomes made of two sister chromatids

Early & Late Prophase

• Chromatin condenses into chromosomes. • Nuclear membrane & nucleolus disappear. • Spindle apparatus forms.

MetaphaseCentrosome

Centromere

Equator or metaphase plate

Metaphase

• Chromosomes line up at imaginary line in the middle of the cell.

• Spindle apparatus is attached to the centromeres.

AnaphaseCentrosome

Shortening spindle apparatus

Anaphase

• Spindle apparatus shortens and chromatids are pulled apart.

Telophase & Cytokinesis

Animal cell “cleavage furrow”ORPlant cell “cell plate”

Chromosomes relaxing

Nuclear membrane reforming

Telophase & Cytokinesis

• Chromosomes arrive at opposite ends of the cell and begin to relax.

• Nuclear membranes reform and nucleoli reappear.

• Spindle apparatus disassembles.

Telophase & Cytokinesis

• Begins towards the end of mitosis.

• Microtubules help organelles and cytoplasm divide.

What’s the end product?

• Two identical daughter cells ready to start the cycle again… or not.

• Some cells (like your nerve and muscle cells) do not undergo division.

• For those that do (your skin and the lining of your intestinal tract) how would you know how quickly division takes place?

RE-identify the stages of Mitosis