What do telomeres and telomerase have to do with cellular theories of aging?
ANSWER:
Some theories of aging propose that the number of times cells can divide is directly related to the length of life span of an organism. The tips of chromosomes, called telomeres, help regulate cell division. Evidence suggests that telomeres adjust a cell's response to stress and growth stimulation based upon cell divisions and DNA damage. The enzyme, telomerase, is needed in DNA replication to fully reproduce telomeres when cells divide. But telomerase is usually not present in somatic cells when they divide. The result is that with each cell division, the telomeres become shorter.
Eventually, chromosomes can't replicate because the telomeres have become too short.
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One in eight U.S. prisoners is incarcerated in:
a. California b. Florida c. New York d. Texas
Since 1950, the number of physicians in the United States has
a. declined slightly. b. declined sharply. c. risen slightly. d. risen sharply. e. remained stable.
One suggested consequence of modernization is movement toward a "symmetrical society." This means:
a. a higher average level of education b. greater economic equality among all groups in society c. greater equality between men and women d. greater political equality
An emphasis on concerns such as ethnic food or political issues rather than on deeper ties to one's ethnic heritage is referred to as
A. ethnocentrism. B. assimilation. C. White privilege. D. symbolic ethnicity.