Bio NOTES: Regulation of the Cell Cycle Factors that regulate cell division: 1. internal factors 2. external factors 3. apoptosis Internal Factors - come from inside the cell and are triggered by external factors Cell growth and division must be controlled and regulated within the cell or serious problems can occur, like cancer. cyclins - proteins that activate kinases - rapidly made and destroyed at certain points of cell cycle
External Factors External factors – come from outside the cell, from nearby cells and distant parts of body 2. growth factors - growth factors are proteins that stimulate cell division - these come from other cells - cells grow and divide in response to a combination of different growth factors, not just one Include physical and chemical signals: 1. cell-to-cell contact - once a cell touches other cells, it stops dividing 3. hormones - may stimulate the growth of certain cell types - one growth hormone results in bone growth
webbed fingers Uses of apoptosis: - embryonic and infant development - cell death of old cells Apoptosis Apoptosis – programmed cell death (cell suicide) - caused by a cell’s production of self-destructive enzymes - it is a normal feature of healthy organisms In early stages of development, human embryos have webbing between fingers and toes. These cells typically go through apoptosis before a baby is born. - the nucleus will shrink and break apart, and cells from the immune system will gobble up the cell and recycle its parts
Cancer is caused by changes in the genes that control normal cell growth and death Cancer occurs when cells continue to grow and divide and do not die when they should What is Cancer? Cancer Basics cancer cell bloodstream normal cell - Benign tumors remain clustered and can be removed. - Malignant tumors metastasize, or break away, and can form more tumors. Cancer cells form disorganized clumps called tumors.
The changes that cause cancer may be inherited, or may result from environmental or lifestyle factors. Causes of Cancer: external factors – tobacco, chemicals, radiation, and infectious organisms internal factors – inherited mutations, hormones, disease Treatments for Cancer: surgery, radiation, chemotherapy, hormones, and immunotherapy carcinogen – any substance known to produce or promote the development of cancer * radiation – uses radiation to kill cancer cells in a specific region * chemotherapy – uses drugs to kill actively dividing cells - both of these also kill healthy cells
Tumors are present during 2 nd stage metastisis = when cancer spreads to other parts of body
Carcinogen Group Study Review list of carcinogen Research 10 carcinogens Summarize and prepare a brochure to inform your peers about them