The two types of chromatin, heterochromatin and euchromatin, are functionally and structurally distinct regions of the genome. Heterochromatin is densely packed and inaccessible to transcription factors so it is rendered transcriptionally silent (Richards and Elgin 2002).
Why is euchromatin transcriptionally active?
In other words, because euchromatin is present in transcriptionally active cells because of the accessibility to the DNA, folding into heterochromatin may be a way to regulate transcription by preventing the access of RNA polymerases and other regulatory proteins to the DNA.
What does transcriptionally active mean?
Term: transcriptionally active chromatin. Definition: The ordered and organized complex of DNA and protein that forms regions of the chromosome that are being actively transcribed.
Which of the following is transcriptionally inactive?
Heterochromatin is transcriptionally inactive when compared to euchromatin.
What is the difference between chromatin and chromatid?
As mentioned above, chromatin is composed of DNA and histones that are packaged into thin, stringy fibers. The chromatin undergoes further condensation to form the chromosome. … A chromatid is either of the two strands of a replicated chromosome. Chromatids connected by a centromere are called sister chromatids.
What is true euchromatin?
Euchromatin is a lightly packed form of chromatin (DNA, RNA, and protein) that is enriched in genes, and is often (but not always) under active transcription. Euchromatin comprises the most active portion of the genome within the cell nucleus. 92% of the human genome is euchromatic.
Which portion of chromosome is transcriptionally active?
For example, all human chromosomes 1, 9, 16, and the Y-chromosome contain large regions of constitutive heterochromatin. In most organisms, constitutive heterochromatin occurs around the chromosome centromere and near telomeres.
What is the difference between heterochromatin and euchromatin?
Heterochromatin is defined as the area of the chromosome which is darkly stained with a DNA specific stain and is in comparatively condensed form. Euchromatin is defined as the area of the chromosome which is rich in gene concentration and actively participates in the transcription process.