November 7, 2007 Set up a new assignment sheet on Page 18. Copy the daily objective from the main board and the assignment from the homework board. Set up a new Table of Contents on Page 19

Set Up Page 21: Cell Reproduction Notes (Eukaryotes) Chromosome long strand of DNA that has many genes located on it Chromatids two identical pieces of DNA connected to one another at a centromere Mitosis process cells use for reproduction, growth and repair Inter-phase Pro-phase Meta-phase Ana-phase Telo-phase Description Diagram

Mitosis and Cancer Today you will learn about the process of mitosis(normal cell division) and what can happen if the cell cycle becomes mutated (abnormal cell division).

Abnormal Cell Growth

Abnormal Cell Growth

Abnormal Cell Growth-Nerve Tumors

A Large Abdominal Tumor

Surgical Removal of Tumor

Body without Tumor

MITOSIS

Why do cells divide? Reproduction Growth Repair

MITOSIS nuclear division number of chromosomes remains the same

Interphase technically not part of mitosis, but it is included in the cell cycle cell is in a resting phase performing cell functions DNA replicates (copies) organelles double in number, to prepare for division

Interphase G1 - (Growth 1) S - (Synthesis) - DNA copies G2 - (Growth 2) - cell prepares for division

Interphase (inter = between) The "holding" stage or the stage between two successive cell divisions. ~90 percent of a cell's time in the normal cellular cycle may be spent in interphase.

Prophase (pro=primary,first) In prophase, the chromatin condenses into discrete chromosomes. The nuclear envelope breaks down and spindles form at opposite "poles" of the cell.

What is chromatin? When a cell is "resting" i.e. not dividing, the chromosomes are organized into an entangled structure called chromatin

Prophase Key Events Chromatin coils to form visible chromosomes In animals, centrioles begin to migrate to opposite poles Spindle forms

Metaphase (meta is like middle) In metaphase, the chromosomes are aligned at the metaphase plate (the middle of the cell).

Anaphase ana=upward,back The centromeres divide and the paired chromosomes (sister chromatids) move to opposite ends of the cell.

Telophase (telo=end) In this last stage, two distinct daughter cells are formed after the chomatids have migrated to the opposite poles. Cytokinesis is also occurring at this time.

Cytyokinesis Cyto =cell Kinesis=movement The cell’s cytoplasm divides at the end of telophase Animals - cell pinches inward Plants - a new cell wall forms between the new cells

Results of Mitosis The cell is the most basic unit of organization In animals… cells-->tissue-->organs-->organ systems -->organisms

The Cell Cycle Proteins called cyclins and enzymes that attach to the cyclins and become activated control the cell cycle

Cancer Occasionally, cells lose control of the cell cycle This results from: failure to produce certain enzymes, the overproduction of enzymes Or the production of enzymes at the wrong time.

Cancer Cancer is a malignant growth resulting from uncontrolled cell division Malignant =dangerous to health; marked by uncontrolled growth

Tumors Tumors are abnormal growth of cells Benign tumors are non cancerous and and only grow locally Malignant tumors are cancerous and spread to other areas of the body

Cancer Cancer is the second leading cause of death in the U.S. Lung, colon, breast, and prostate cancers are the most prevalent types

Causes of cancer Genetics Environmental Factors Cigarette smoke Air and water pollution Exposure to UV radiation However, there are still unknown causes and researchers are working to discover these factors.

Cancer prevention Healthy Lifestyle Low fat, high fiber diet Exercise Not smoking Taking daily vitamins and minerals Carotenoids, Vitamins A, C, E, and calcium

Cancer Cancer is difficult to treat in later stages because the cancer may have spread to vital organs and damaged them beyond repair. Today we will see a short video that shows how widespread cancer can affect the body.