The Cell Cycle and Cancer

The Stages of the Cell Cycle 1. Click on picture for cell cycle animation – will go to www.cancerquest.org) 2. Use alt-tab keys to go between website and power point presentation. 3. Click on blank space to proceed to next slide.)

  SCI.9-12.B-2.7 - [Indicator] - Summarize how cell regulation controls and coordinates cell growth and division and allows cells to respond to the environment, and recognize the consequences of uncontrolled cell division.

There are several factors that regulate the cell cycle and assure a cell divides correctly. 1.Before a cell divides, the DNA is checked to make sure it has replicated correctly. (If DNA does not copy itself correctly, a gene mutation occurs. DNA replication animation:click on DNA picture

2. Chemical Signals tell a cell when to start and stop dividing. (Target cells animation: click on go sign)

3. Contact inhibition – Cells grow until they touch each other and then they stop growing and dividing. (Normal contact inhibition animation: click on petri dish)

Cancer is a disease of the cell cycle Cancer is a disease of the cell cycle. Some of the body’s cells divide uncontrollably and tumors form. Tumors in Liver Tumor in Colon

DNA mutations disrupt the cell cycle. Mutations may be caused by: 1. radiation 2. smoking 3. Pollutants 4. chemicals 5. viruses CARCINOGENS

While normal cells will stop dividing if there is a mutation in the DNA, cancer cells will continue to divide with mutation.

Due to DNA mutations, cancer cells ignore the chemical signals that start and stop the cell cycle. 2 animations of cancer cells dividing: click on picture

  SCI.9-12.B-2.7 - [Indicator] - Summarize how cell regulation controls and coordinates cell growth and division and allows cells to respond to the environment, and recognize the consequences of uncontrolled cell division.

Due to DNA mutations, cancer cells cannot communicate with neighboring cells. Cells continue to grow and form tumors. Skin cancer (cancer cells dividing: click on picture.)

SUMMARY Normal Cell Division DNA is replicated properly. 2. Chemical signals start and stop the cell cycle. 3. Cells communicate with each other so they don’t become overcrowded. Cancer Cells Mutations occur in the DNA when it is replicated. 2. Chemical signals that start and stop the cell cycle are ignored. 3. Cells do not communicate with each other and tumors form.

Benign tumours do not spread from their site of origin, but can crowd out (squash) surrounding cells eg brain tumors . Malignant tumours can spread from the original site and cause secondary tumours. This is called metastasis. They interfere with neighbouring cells and can block blood vessels, the gut, glands, lungs etc. Metastasis – when cancer cells spread from one part of the body to another part.

Treating Cancers Cancer treatments include drugs that can stop cancer cells from dividing.

Cancer is one of the most common diseases in the developed world: 1 in 4 deaths are due to cancer 1 in 17 deaths are due to lung cancer Lung cancer is the most common cancer in men Breast cancer is the most common cancer in women

  SCI.9-12.B-2.7 - [Indicator] - Summarize how cell regulation controls and coordinates cell growth and division and allows cells to respond to the environment, and recognize the consequences of uncontrolled cell division.