Control of the Cell Cycle

Cancer

Objectives Why do some types of cells divide rapidly,

while others divide slowly?

What tells a cell when it is time to leave one part of the cell cycle and begin the next?

Proteins and enzymes control cell cycle

What controls the cell cycle: Cyclins (protein) and a set of enzymes that

attach to the cyclin and become activated The interaction of these molecules based on the

conditions in and out of the cell, control the cell cycle

Enzyme Production Directed by genes on the chromosomes

What is a gene? Segment of DNA that controls the production of

protein

Many studies point to the portion of interphase just before DNA replication as the key control period in the cell cycle

What causes cancer? Occasionally, cells lose control of the cell

cycle What causes them to lose control?

Failure of cell to produce certain enzymes Overproduction of enzymes Production of enzymes at the wrong time Environmental factors

Cancer – malignant growth resulting from uncontrolled cell division

Lung Cancer

Cancer Is caused by 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 involved in controlling the cell cycle. Changes are expressed as cancer when

something prompts the damaged genes into action

Cancer Cancerous cells form masses of tissue called

tumors that deprive normal cells of nutrients. In later stages, cancer cells enter the

circulatory system and spread throughout the body (metastasis) Form new tumors that disrupt the function of

organs, organ systems and ultimately the organism

Cancer 2nd leading cause of death in the US,

exceeded only by heart disease

Can affect any tissue in the body

Most prevalent cancers in the US: lung, colon, breast and prostate

Causes of Cancer Involve both genetic and environmental factors Different cancers are more prevalent in different

parts of the world Environmental

Cigarette smoke, air and water pollution, exposure to UV rays from the sun

Genetic Viral infections that damage the genes Carrier of gene that makes you at higher risk (breast

cancer: BRCA1, BRCA2 gene)

Cancer Prevention Scientists have established a clear link between a healthy lifestyle

and the incidence of cancer Diets low in fat and high in fiber

Diets high in fat are linked to increased risk of breast, colon and prostate cancers

People who limit fat intake reduce their risk and also maintain a healthy body weight

High fiber diets linked to a reduced risk of colon cancer Fruits, vegetables and grains = high fiber content

Vitamins and minerals may also help to prevent cancer Keys in this category: caratenoids, Vit A, C & E, calcium

Caratenoids and Vit A yellow & orange vegetables, and green leafy vegetables

Vitamin C citrus fruits Vitamin E SUN Calcium dairy products

Making healthy choices, exercising and avoiding carcinogens help to reduce your risk for cancer