Eukaryotic-like (possessing a defined nucleus)cells were obtained from a Martian soil sample.The nucleus was carefully isolated and the chromatin obtained.The fibers had a "beads on a string" appearance,suggesting some type of "histones." Following digestion with micrococcal nuclease,protein removal,and gel electrophoresis,DNA fragments were obtained that are multiples of 280 base pairs in length.Longer incubation with micrococcal nuclease prior to protein removal results in fragments 200 base pairs in length.The amount of DNA that is wrapped around the "core histones" is therefore
A)80 base pairs in length.
B)200 base pairs in length.
C)360 base pairs in length.
D)480 base pairs in length.
E)Not enough information is given to determine the answer.

Question

Quizplus · Accepted Answer

The fact that the DNA fragments obtained after digestion with micrococcal nuclease and protein removal are multiples of 280 base pairs in length indicates that each nucleosome consists of approximately 147 base pairs of DNA wrapped around a core of histone proteins. Therefore, the amount of DNA wrapped around the "core histones" is likely to be around 200 base pairs in length, which is the length of the DNA fragments that are obtained after longer incubation with micrococcal nuclease.

Eukaryotic-Like (Possessing a Defined Nucleus)cells Were Obtained from a Martian