HIV, the virus that causes AIDS, depends on an enzyme called reverse transcriptase to multiply. Reverse transcriptase reads a molecule of RNA and creates a molecule of DNA from it. A molecule of AZT, an anti-AIDS drug, has a shape very similar to (but a bit different than) that of the DNA base thymine. Propose a model for how AZT inhibits HIV.

To answer this question, researchers studied populations of the dusky salamander (desmognathus ochrophaeus) living on different mountain ranges in the southern appalachian mountains. the researchers tested the reproductive isolation of pairs of salamander populations by leaving one male and one female together and later checking the females for the presence of sperm. four mating combinations were tested for each pair of populations (a and b)—two within the same population (female a with male a and female b with male b) and two between populations (female a with male b and female b with male a). the proportion of successful matings for each mating combination was measured. for example, when all the matings of a particular combination were successful, the researchers gave it a value of 1; when none of the matings were successful, they gave it a value of 0. then the researchers calculated an index of reproductive isolation that ranged from 0 (no isolation) to 2 (full isolation). the reproductive isolation value for two populations is the sum of the proportion of successful matings of each type within populations (aa + bb) minus the sum of the proportion of successful matings of each type between populations (ab + ba). the table provides data for the geographic distances and reproductive isolation values for 27 pairs of dusky salamander populations.

This question is only for applicants to scholars for medicine or scholars for dental medicine: what aspects about medicine (or dental medicine) intrigue you? describe how these aspects influence your life. (100-650 words)

How many chromosomes does each human cell contain? a. 23 chromosomes b. 26 chromosomes c. 43 chromosomes d. 46 chromosomes