Coiling of chromatids during cell division?

Question

What is exactly coiling of chromosomes?I just heard about the names i.e paranemic, plectonemic, orthostichious, anorthospiral.I have ecaxtly no idea of what phenomenon is this.Also what type of coiling occurs during meiosis and mytosis type of cell division.Could it be explained in detail....?

Answer 1

In a basic sense, DNA in chromosomes is commonly referred either be in a heterochromatin or euchromatin state. Heterochromatin refers to sections of DNA that is tightly bundled together and thus does not easily allow other machinery (ie. polymerases) to come into contact with it. Thus, this "silences" or suppresses these genes. The increased tightness of the bundling is accomplished through histones, which create octomers that wrap DNA around themselves. These can be tightly connected in heterochromatin or loosely bundled in euchromatin. During cell division, after the chromosomes have been copied, they are coiled tightly and compressed (heterochromatin) in order to be brought to opposite sides of the cell in the dividing process. The density of the chromosomes makes them easier to move and less likely for error to occur.