THE CELL
CELL COMMUNICATION
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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a receptor molecule that is always turned off
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a target protein that is always activated
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a gene for cell division that is expressed when it should not be
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a receptor molecule that is always activated
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a transduction pathway that is always turned on
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Detailed explanation-1: -In certain cancerous cells, the cell divides continuously even in the absence of a growth factor (signaling molecule) that indicates the cell should divide. Which of the following could NOT explain this? Radioactive isotopes are used to tag proteins in the cell membranes of mouse cells.
Detailed explanation-2: -Overexpression of growth factors or a lack of suppressor proteins can lead to rapid uncontrolled cell division. As cells proliferate without regulation, tumors occur that can become deadly if not treated.
Detailed explanation-3: -Cancer cells behave differently than normal cells in the body. Many of these differences are related to cell division behavior. For example, cancer cells can multiply in culture (outside of the body in a dish) without any growth factors, or growth-stimulating protein signals, being added.
Detailed explanation-4: -While normal cells will stop division in the presence of genetic (DNA) damage, cancer cells will continue to divide. The results of this are ‘daughter’ cells that contain abnormal DNA or even abnormal numbers of chromosomes. These mutant cells are even more abnormal than the ‘parent’ cell.