Cell Cycle Essay

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The cell cycle is the process by which cells progress and divide. In normal cells, the cell cycle is controlled by a complex series of signaling pathways by which a cell grows, replicates it’s DNA and divides, these are called proto-oncogenes. A proto-oncogene is a normal gene that could become an oncogene due to mutations. This process has mechanisms to ensure that errors are corrected, if they are not, the cells commit suicide (apoptosis). This process is tightly regulated by the genes within a cell’s nucleus. In cancer, as a result of genetic mutations, this process malfunctions, resulting in uncontrolled cell proliferation. Mutations in proto-oncogene or in a tumour suppressor gene allow a cancerous cell to grow and divide without the normal control imposed by the cell cycle. A change in the DNA sequence of the proto-oncogene gives rise to an oncogene, which …show more content…

However, tumours can spread into some tissues more easily than others. For example, large blood vessels that have very strong walls and dense tissues such as cartilage are hard for tumours to grow into.
Pressure from the growing tumour, means that it takes up more space, it begins to press on the normal body tissue nearby. The tumour growth will force itself through the normal tissue. Cancers may grow between sheets of muscle tissue rather than straight through one particular muscle. As the cancer grows, it will squeeze and block small blood vessels in the area. Due to low blood and oxygen levels, some of the normal tissue will begin to die off. This makes it easier for the cancer to continue to push its way through.
Some normal cells produce chemicals called enzymes that break down cells and tissues. The cells use the enzymes to attack invading bacteria and viruses. They also use them to break down and clear up damaged areas in the body. The damaged cells are cleared away so the body can replace them with new ones.

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