Cell Division The Cell Cycle

Cell Cycle Cell Cycle: regular sequence of growth and division that cells undergo. Stage 1: INTERPHASE Period before cell division. The cell is growing and copying its DNA. It is preparing to divide into two cells.

Interphase growing– the cell is grows to full size and produces structures it needs. Copying DNA– the next part of interphase, the cell is copying DNA, this is called replication. The cell contains 2 sets of DNA at the end of replication. Preparing for Division: the cell produces structures that it will use to divide into 2 new cells.

Stage 2: Mitosis Mitosis: the stage in which the cell’s nucleus divides into 2 new nuclei. During Mitosis, one copy of the DNA is distributed into each of the two daughter cells.

Mitosis A: Prophase: Chromatin in the nucleus condenses to form chromosomes. – double rod like structures. The pairs of centrioles move to opposite sides of the nucleus. Spindle fibers from a bridge between ends of the cell. The nuclear envelope breaks down.

Mitosis B: Metaphase The chromsomes line up across the centremere of the cell. Each chromosomes attaches to a spindle fiber at its centromere.

Mitosis C: Anaphase The centromeres split. The two chromatids split. One chromatid is drawn by its spindle fiber to one end of the cell. The other chromatid moves to the opposite end. The cell stretches out as the opposite ends are pushed apart.

Mitosis D: Telephase The Chromosomes begin to stretch out and lose their rod-like appearance. A new nuclear envelope forms around each region of chromosomes.

Cytokinesis The cell membrane pinches in around the middle of the cell. The cell splits in two. Each daughter cell ends up with an identical set of chromosomes and about half the organelles.

Cell Cycle