Controlling the Cell Cycle

Controlling the Cell Cycle The controls on cell growth and division can be turned on and off. For example, when an injury such as a broken bone occurs, cells are stimulated to divide rapidly and start the healing process. The rate of cell division slows when the healing process nears completion.

Controlling the Cell Cycle Recall that proteins are made by ribosomes.  

Controlling the Cell Cycle Recall that proteins are made by ribosomes.   Certain class of proteins called cyclins help control different phases of the cell cycle. Ex. S-cyclin—helps stimulate DNA replication in S phase (interphase)

M-cyclin—triggers mitosis Cyclins are influenced by another protein called growth factors.

The Discovery of Cyclins Cyclins are a family of proteins that regulate the timing of the cell cycle in eukaryotic cells. This graph shows how cyclin levels change throughout the cell cycle in fertilized clam eggs.

Growth factors supervise and monitor cells progress through the place of the cell cycle. --may promote or prevent certain cycles

Cancer arises from a faulty cell cycle is a term to describe a disease characterized by uncontrolled cell division and growth without regulation of the cell cycle, cell will grow without restraint.  

Tumor —is a clump of cells that is not regulated Benign—harmless tumor Malignant—grows and invades other cells

Tumor A benign tumor is noncancerous. It does not spread to surrounding healthy tissue. A malignant tumor is cancerous. It invades and destroys surrounding healthy tissue and can spread to other parts of the body. The spread of cancer cells is called metastasis. Cancer cells absorb nutrients needed by other cells, block nerve connections, and prevent organs from functioning.

Picture from study.com:

Tumor sizes Vary

Examples of Tumor Size… Caution next slide may be disturbing for some people…

Example of Tumor sizes

--faulty cell can produce many changes in a cell, making them different from normal cell --cancer cell more round and mobile than normal

Cell cycle is regulated in several ways and all must be damaged for cancer to occur

Carcinogens —cancer causing to cells Ex. Smoking, UV rays, radiation, lead

Carcinogens —cancer causing to cells Ex. Smoking, UV rays, radiation, lead

A change in your genes, mutation, usually occurs in lungs or skin cells and usually not hereditary

If genes in either egg or the sperm are mutated, then there is a greater chance of cancer later in the life of the “new baby”

Prevention proper diet exercise avoid carcinogens (smoke, chemicals, radiation) UV protection not smoking

Treatment: 1. Radiation Therapy 2. Chemotherapy (“Smart Bomb”) 3. Both (with or without surgery) 4. Surgery