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Biology – The Building Blocks of Life Objectives: – Describe normal cell growth and its limits – Define the causes and effects of cancer Limits for Cell Growth – A cell has one set of DNA TRUE – One set of DNA can regulate a cell that is any size FALSE – one set of blueprints is NOT enough to build the biggest building Limits for Cell Growth – All nutrients & waste pass through the cell membrane TRUE – When a cell’s inside volume double, so too does the outside surface area FALSE The internal volume of a cell grows faster than the outside boundary (membrane) Surface to Volume Ratio Break apart Grow Radius Surface 4pr2 Volume 4/3pr3 S/V Ratio 1.0 3.0 1.0 12.6 113.1 339.4 4.2 113.1 113.1 3 1 3 Limits for Cell Growth (continued) – A larger cell has a hard time getting nutrient in and waste out of the cell TRUE – A cell undergoes division to solve its size problems TRUE Controls of Cell Growth Muscle and Nerve cells do not divide…EVER! – TRUE Cells stop dividing when they touch another cell – TRUE Controls of Cell Growth Mitochondria dictate when a cell will divide – FALSE – the nucleus (DNA, chromosomes) dictates when a cell will divide Cell division can speed up & slow down under certain conditions – TRUE - (Injury, change in genetics, chemicals) Cell Cycle Regulators The protein that controls cell division is called Dividein – FALSE…the name of the protein is CYCLIN Injury can speed up the timing of the cell cycle. – TRUE Uncontrolled Cell Growth Cancer = the cell’s inability to control its own growth – TRUE, by definition Tumors take up space & nutrients that normal cells need to survive – TRUE It is normal for a cell to uncontrollably divide every now and then – FALSE – that would be CANCER Causes of Cancer Cancer MUST come from a change in genetics!!! – Radiation Sun’s UV rays, X-rays, nuclear – Chemicals Nicotine, toxic waste, other chemicals – Viruses ONLY IF it changes your DNA – Genetic mutations (inherited) In the spot that regulates cell division Treatments for Cancer Radiation – “zap” the uncontrolled cells. You better kill them all. Miss one, it will start uncontrollablly dividing again! Surgery – Cut out the bad cells. You better get them all…or… Chemotherapy – Use chemicals to slow down all cell division in your body. Leads to hair loss, stomach problems, weakness, etc.