MITOSIS

10X Magnification of Stained Human Cheek Cells

Parts of the Human Cheek Cell at 40X Magnification

Can you name these parts of the Human Cheek Cell?

CELL CYCLE

During Interphase DNA replicates which must occur before Mitosis can begin .

Centrioles : Nuclear division

View of onion root tip under low power

MITOSIS – ONION ROOT TIP Interphase Prophase Later Prophase Metaphase Early Anaphase Anaphase Telophase Later Telophase

STAGES OF MITOSIS IN WHITEFISH BLASTULA

Interphase This cell is shown, as this is how all cells look before mitosis. Please be aware that Interphase is a phase of the cell cycle, but NOT a stage of mitosis.

Mitosis - Early Prophase To begin mitosis, the nuclear membrane breaks down, while the chromosomes shorten and thicken (here, a chromosome is two chromatids, bound at a point called the centromere, making an "X" shape). The other structures important for mitosis are also forming (i.e. the centrioles).

Mitosis - Metaphase The spindle has now formed and the nuclear membrane has broken down. The chromosomes are lined up along the cell's center and are attached to the spindle fibers. When the individual chromatids (½ of the "X") are separated from the chromosome (the "X"), they are now each referred to as a chromosome (i.e. In metaphase, the chromosome, composed of two chromatids, separates into the individual chromatids, which are then renamed chromosomes).

Mitosis - Anaphase The newly formed chromosomes are pulled along the spindle toward opposite poles of the cell.

Mitosis - Telophase The chromosomes have finished their migration to the poles. The spindle has broken down and disappeared. The cell membrane pinches in (forms a cleavage furrow) along the center creating two separate cells . At this time, the chromosomes uncoil and become less visible (as they are during Interphase), the nuclear membrane reforms. The division of the cytoplasm is called cytokinesis. The division of the nucleus is Mitosis. At the end of Telophase, the cell reenters Interphase.

The X is pointing to what structure?

Stay tuned for another activity. What is this???? Stay tuned for another activity.

Alabama State University, Math, Science Partnership, Winter,2013 Prepared by: Dr. Debbie Payne, Ruth H. Liddell, Shirley K. Scarbrough Alabama State University, Math, Science Partnership, Winter,2013