Answer:
b
Explanation:
im not 100% sure the all have common symptom's.
Answer:
Okay
Explanation:
Human topoisomerase I plays an important role in removing positive DNA supercoils that accumulate ahead of replication forks. It also is the target for camptothecin-based anticancer drugs that act by increasing levels of topoisomerase I-mediated DNA scission. Evidence suggests that cleavage events most likely to generate permanent genomic damage are those that occur ahead of DNA tracking systems. Therefore, it is important to characterize the ability of topoisomerase I to cleave positively supercoiled DNA. Results confirm that the human enzyme maintains higher levels of cleavage with positively as opposed to negatively supercoiled substrates in the absence or presence of anticancer drugs. Enhanced drug efficacy on positively supercoiled DNA is due primarily to an increase in baseline levels of cleavage. Sites of topoisomerase I-mediated DNA cleavage do not appear to be affected by supercoil geometry. However, rates of ligation are slower with positively supercoiled substrates. Finally, intercalators enhance topoisomerase I-mediated cleavage of negatively supercoiled substrates but not positively supercoiled or linear DNA. We suggest that these compounds act by altering the perceived topological state of the double helix, making underwound DNA appear to be overwound to the enzyme, and propose that these compounds be referred to as ‘topological poisons of topoisomerase I’
Answer: d. Confounding
Explanation:
In the context of a scientific study such as this one, a confounding factor is one that has influence on both the exposure and event variable(s), which may lead to over- or underestimation of the direct relationship between them (if any).
For instance: In this example, researchers may have had reason to believe that male gender is associated with both higher risk of obesity (the exposure variable) and adult-onset asthma (the event variable). If gender is not taken into account, one may claim that the finding of an association between obesity and asthma is simply an artifact due to the high proportion of male patients (likely to present with both). <em>Controlling</em> for that variable (such as by matching, as in this example) allows researchers to test for this hypothesis.
