Unusual eukaryotic-like (possessing a defined nucleus)cells were obtained from a sample of water from a subglacial antarctic lake.To investigate the properties of the new organism's genome,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 DNA fragments obtained after digestion with micrococcal nuclease and protein removal are multiples of 280 base pairs in length, indicating the length of DNA wrapped around the histone core plus the linker DNA. Longer incubation results in 200 base pair fragments, which suggests that this is the length of DNA directly associated with the histone core, as the linker DNA is digested away.

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