The Cell Cycle Mitosis

The Cell Cycle The regular sequence of growth and division that cells undergo.

The Cell Cycle 6 Parts Interphase Prophase* Metaphase Anaphase Telophase Cytokinesis *When mitosis begins.

Stage 1: Interphase During interphase the cell grows, makes a copy of its DNA, and prepares to divide into 2 cells. Cell grows - The cell grows to full size and produces structures it needs. Copies DNA -Cell makes a full copy of the DNA. This process is known as replication. DNA is found in the chromatin.

Stage 1: Interphase Preparing for Division - After replication has occurred, the cell copies its centrioles. Centrioles - Cylindrical structures that produce microtubules used in mitosis.

Stage 2: Mitosis Mitosis - The stage during which the cell’s nucleus divides into two new nuclei. During mitosis, one copy of the DNA is distributed into each of the two daughter cells. Daughter cells - The cells that are produced following cell division.

Stage 2: Mitosis Part 1 Prophase - Chromatin condenses in the nucleus to form chromosomes. Chromosomes are made of chromatin. The two chromatids that make up a chromosome is held together in the center by a centromere. (make a diagram.) The centrioles move to opposite sides of the nucleus. The nuclear envelope breaks down.

Stage 2: Mitosis Part2 Metaphase - Chromosomes line up across the center of the cell. Each chromosome attaches to a spindle fiber at its centromere. The spindle fibers are connected to the centrioles.

Stage 2: Mitosis Part 3 Anaphase - The centromeres split, and the chromatids separate. Each chromatid becomes a new chromosome. New chromosomes move to opposite ends of the cell. Cell begins to stretch out as the opposite ends are pushed apart.

Stage 2: Mitosis Part 4 Telophase - Chromosomes lose their rod-like appearance New nuclear envelope forms around the bundle of chromosomes. Two halves separate even farther.

Stage 3: Cytokinesis Cytokinesis is the division of cytoplasm and organelles into each of the 2 new cells.

Stage 3: Cytokinesis During cytokinesis: Cell membrane pinches in around the middle of the cell. Cell splits in two and divides the cytoplasm. Each daughter cell has an identical set of chromosomes and about 1/2 the organelles. Cytokinesis leads back into interphase.

Stage 3: Cytokinesis Cytokinesis in PLANTS is different. A cell plate forms across the middle of the cell, which gradually develops into the new cell membranes. The new cell walls form around the cell membranes.

DNA Structure Double helix - Twisted ladder shape The sides of the ladder are made up of sugar molecules called deoxyribose, and alternate with a phosphate molecule. The rungs are made up of a pair of nitrogen bases. 4 nitrogen bases: adenine (A), thymine (T), guanine (G), and cytosine (C).

DNA Replication Process The DNA “ladder” unwinds and unzips, leaving 1 of the 2 nitrogen bases on either side of the “ladder”. Bases that are floating in the nucleus pair up with its appropriate partner. Adenine pairs with Thymine Guanine pairs with Cytosine