po
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In an experiment, it is observed that chronic, increased exposure to ionizing radiation results in damage to cellular DNA. As a consequence, a protein is now absent that would arrest the cell in the G1 phase of the cell cycle. Subsequent to this, the cell is transformed to acquire the property of unregulated growth. The absent protein is most likely the product of which of the following genes?
A k-ras
B p53
C c-myc
D c-abl
E Bcl-2
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| SmokyWaters
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p53
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| SmokyWaters
Forum Elite
Topics: 6
Posts: 447
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that wud be B
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| po
Forum Elite
Topics: 39
Posts: 356
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(B) CORRECT. Abnormal p53 has been identified in many carcinomas. This loss of normal tumor suppression leads to development of carcinomas.
(A) Incorrect. The k-ras oncogene 'turns on' cells to promote carcinogenesis.
(C) Incorrect. The c-myc oncogene 'turns on' cells to promote carcinogenesis.
(D) Incorrect. The c-abl fusion gene results from a 9:22 translocation (Philadelphia chromosome of chronic myelogenous leukemia) that promotes cellular transformation via protein kinases.
(E) Incorrect. The Bcl-2 gene acts by decreasing apoptosis (cell death) to cause accumulation of cells with follicular lymphomas.
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