1. Chromatin exists in two forms: heteroChromatin (condensed) and euChromatin (extended).

2. One form, called euChromatin, is less condensed and can be

3. Traditionally, Chromatin is classified as either euChromatin or heteroChromatin, depending on its level of compaction

4. Specialized Chromatin structures that maintain barriers at the ends of euChromatin and prevent the heteroChromatin from spreading into inappropriate regions

5. EuChromatin has a less compact structure, and is often described as a 11 nm fiber that has the appearance of ‘beads on a string’ where the beads …

6. In previous observations of the frequency of chromosome aberrations in anaphase cells ofAllium cepa irradiated with fast electrons in different depths the varying radiosensitivity in different stages of the cell cycle could be interpreted by assuming a different effect in euchromatin and heterochromatin synthesized at different times.

7. The basic structure of Chromatin—either heteroChromatin or euChromatin—is called the nucleosome.The nucleosome is a complex of 146 base pairs of DNA, wound in two turns around the outside of a disk‐like complex of eight proteins (called histones).The histone core contains two copies each of four histones, H2A, H2B, H3, and H4.