Astudent is working in a dna analysis laboratory and performs numerous dna isolations from eukaryotic cells. however, the student realizes at the end of the day that he forgot to label whether or not the dna samples he isolated were from nuclei or mitochondria. which of the following would not be a strategy the student could use to determine the origin of his dna isolates? a) the student could determine whether histones were present or not in each sample. b) the student could determine if the sample absorbed light of 260 nm. c) the student could compare whether the dna in each sample was circular or linear. d) the student could measure the average size of the dna isolated in each sample.

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.

Multicellular organisms use cell division, mitosis, for growth and the maintenance and repair of cells and tissues. single-celled organisms may use cell division as their method of reproduction. regardless of the reason for mitosis, the process ensures genetic continuity. what is the step in the cell cycle that ensure genetic continuity?

What is the role of the phospholipid belayer in cellular transport in living cells