OBJECTIVE LIFE SCIENCE
CELL BIOLOGY
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Divide about 40-60 times before they “grow old” and die
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Respond to cell cycle regulator signals to stop dividing
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When cell has damaged DNA the cell dies
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Ignore signals to stop dividing, respond to positive and negative factors
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Divide many more times than normal cells
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Detailed explanation-1: -The engulfed dead cells will enter lysosomes, and their DNA is degraded by a lysosomal enzyme(s). On the other hand, if massive cell death is induced by -rays, the capacity of phagocytes to engulf the cells is exceeded, and the corpses with their TUNEL-positive nuclei are left unengulfed.
Detailed explanation-2: -Normally, human cells grow and multiply (through a process called cell division) to form new cells as the body needs them. When cells grow old or become damaged, they die, and new cells take their place. Sometimes this orderly process breaks down, and abnormal or damaged cells grow and multiply when they shouldn’t.
Detailed explanation-3: -Apoptosis is the process of programmed cell death. It is used during early development to eliminate unwanted cells; for example, those between the fingers of a developing hand. In adults, apoptosis is used to rid the body of cells that have been damaged beyond repair. Apoptosis also plays a role in preventing cancer.