Some genes associated with cancer Cell cycle Those 2 cells then also replicated

Some genes associated with cancer cell cycle those 2

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Some genes associated with cancer
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Cell cycle Those 2 cells then also replicated and divided, so the two cells became four cells. The four cells replicated as well and divided into eight cells, and so on. Cells specialize to perform particular tasks. Some cells will cluster together to form a finger, for example. Others create skin and heal the skin when it is wounded. Cells get old and die after a certain amount of time (“programmed cell death ,” or apoptosis ), and replication ensures that new cells are made to take their place. When they are acting normally, cells “know” which other cells to join up with and stick to – and they also know when to stop replicating and die. Each type of cell has a particular role and set of knowledge or instructions in their DNA (genes ). Our cells know how to make the right number of fingers on our hand for us (and they know that fingers should only grow on our hands ). Each finger is covered with skin and each finger has a fingernail. If we cut our finger, the skin cells will start replicating and create new skin to heal the wound . If we lose a fingernail, our cells can grow a new one. But the cells will not create extra fingers , even if we lose one. The rules are clear for those cells, and they keep to the rules. A cancer cell can have thousands of mutations, but only a certain number of these genetic changes in cancer cells cause the cancer to divide and grow. Mutations which result in the growth of the cancer cells are referred to as "driver mutations," whereas other mutations are considered "passenger mutations." The term "oncogenes" refers to genes that drive the growth of the cancer, and give cancer its immortality. Tumor suppressor genes , in contrast, are genes within the cell which tell cells to slow down and stop growing, repair damaged DNA, or tell cells when to die. Most cancer cells have mutations in both oncogenes and tumor suppressor genes which lead to their behavior.
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Cancer cells do not stop dividing, so what stops a normal cell from dividing? In terms of cell division, normal cells differ from cancer cells in at least four ways. • Normal cells require external growth factors to divide. When synthesis of these growth factors is inhibited by normal cell regulation, the cells stop dividing. Cancer cells have lost the need for positive growth factors, so they divide whether or not these factors are present. Consequently, they do not behave as part of the tissue — they have become independent cells. • Normal cells show contact inhibition; that is, they respond to contact with other cells by ceasing cell division. Therefore, cells can divide to fill in a gap, but they stop dividing as soon as there are enough cells to fill the gap. This characteristic is lost in cancer cells, which continue to grow after they touch other cells, causing a large mass of cells to form.
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  • Fall '17
  • DR. MOSLEY

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