CELL STRUCTURES AND FUNCTION
CELL DIVISION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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absence of cyclins in the DNA
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Multiple gene mutations on a chromosome of DNA
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Uncontrolled cell growth caused by mutations in genes that control the cell cycle.
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Presence of genetic defects caused by hereditary disorders.
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Detailed explanation-1: -The overactive (cancer-promoting) forms of these genes are called oncogenes, while the normal, not-yet-mutated forms are called proto-oncogenes. This naming system reflects that a normal proto-oncogene can turn into an oncogene if it mutates in a way that increases its activity.
Detailed explanation-2: -Unlike normal genes, oncogenes cannot be turned off, so they cause uncontrolled cell growth. In normal cells, tumor suppressor genes prevent cancer by slowing or stopping cell growth. DNA changes that inactivate tumor suppressor genes can lead to uncontrolled cell growth and cancer.
Detailed explanation-3: -Cancer is a disease in which some of the body’s cells grow uncontrollably. There are many different types of cancer, and each begins when a single cell acquires a genomic change (or mutation) that allows the cell to divide and multiply unchecked.
Detailed explanation-4: -Oncogenes. These turn a healthy cell into a cancerous cell. Mutations in these genes are not known to be inherited.
Detailed explanation-5: -With increasing cell growth, cancer cells spread or infiltrate to involve other organs, displacing normal tissue and severely depleting nutrient and metabolic resources, which results in death either from cancer cachexia or from mechanical disruption of normal organ function.