Mitosis & Cancer: When Making New Cells Goes Terribly Wrong!. When is mitosis a good thing?. When you have to add or replace cells growth & development repair replacement. Controls on Growth. - PowerPoint PPT Presentation
Mitosis & Cancer:When Making New Cells Goes Terribly Wrong!
1When is mitosis a good thing?When you have to add or replace cellsgrowth & developmentrepairreplacement
Controls on GrowthThe cell cycle is very carefully regulated, and there are two general ways that the growth of cell is limited:External FactorsInternal FactorsExternal FactorsThings that originate from outside the cell environment that regulate the cell cycleContact- cells in contact with other cells usually stop dividing.Growth factors- hormones and proteins that stimulate or repress the growth of cellsInternal FactorsSignals that originate from inside a cell to regulate the cell cycleCyclins- proteins that regulate the division of cellsMay be involved with the timing of events in mitosisGenetic Controls- genes regulate when and how cells divideNormal Control of the Cell Cycle
Proteins and enzymes control the cell cycleThe cell cycle is controlled by proteins called cyclins and a set of enzymes that attach to the cyclin and become activated.Occasionally, cells lose control of the cell cycle.
Normal Control of the Cell Cycle
uncontrolled dividing of cells can result from the failure to produce certain enzymes, the overproduction of enzymes, or the production of other enzymes at the wrong time.Cancer is a malignant growth resulting from uncontrolled cell division.Cancer cells no longer respond to normal signals that regulate division.
Cancer: A mistake in the Cell Cycle
Currently, scientists consider cancer to be a result of changes in one or more of the genes that produce substances that are involved in controlling the cell cycle.Cancerous cells form masses of tissue called tumors that deprive normal cells of nutrients
When is mitosis a BAD thingUncontrolled cell division is not good.When cells reproduce & they are not needed they can take over organs, but no longer function properlythey just keep making copiesThis is cancerdamages organsGrowth of cancers
The causes of cancerThe causes of cancer are difficult to pinpoint because both genetic and environmental factors are involved.Environmental factors, such as cigarette smoke, air and water pollution, and exposure to ultraviolet radiation from the sun, are all known to damage the genes that control the cell cycle. The factors are called carcinogens.Cancer may also be caused by viral infections that damage the genes.
Why would cells just make copies? Mutations: DNA gets damaged, cells stop listening to correct instructions, or lose the correct instructions.Causes of mutations (carcinogens):UV radiationchemical exposureradiation exposureheatcigarette smokepollutionagegenetics12Cancer: A mistake in the Cell Cycle
In later stages, cancer cells enter the circulatory system and spread throughout the body, a process called metastasis, forming new tumors that disrupt the function of organs, organ systems, and ultimately, the organism.
Cancer preventionPhysicians and dietary experts agree that diets low in fat and high in fiber content can reduce the risk of many kinds of cancer.Vitamins and minerals may also help prevent cancer.In addition to diet, other healthy choices such as daily exercise and not using tobacco also are known to reduce the risk of cancer.