details of euchromatin and heterochromatin?

Question

chromosome

Answer 1

Chromatin: Uncoiled, non-condensed piece of DNA (unlike chromosome which are highly condensed) along with the associated histone and non-histone proteins.
There are two types:
1. Euchromatin: which is a partially or fully uncoiled piece of
DNA which is genetically active, other-words active in transcription. Found in BOTH eukarytoes and prokaryotes. In this state they stain little with dyes
2. Heterochromatin: is a state where the chromatin is tightly coiled, hence it stain darker with dyes. It is not available for the RNA polymerase to transcribe it. Generally these are genes that are not expressed in that cell type or inactive satellite sequences, telomers, etc. Heterochromatin is usually localized to the periphery of the nucleus.
This is ONLY found in eukaryotes!

Answer 2

Chromatin is found in two varieties: euchromatin and heterochromatin. Originally, the two forms were distinguished cytologically by how darkly they stained - the former is lighter, while the latter stains darkly, indicating tighter packing. Heterochromatin is usually localized to the periphery of the nucleus.
Euchromatin is a lightly packed form of chromatin that is rich in gene concentration, and is often (but not always) under active transcription. Unlike heterochromatin, it is found in both eukaryotes and prokaryotes.
Heterochromatin mainly consists of genetically inactive satellite sequences,and any genes are repressed to various extents, although some cannot be expressed in euchromatin at all.Heterochromatin also replicates later in S phase of the cell cycle than euchromatin, and is found only in eukaryotes. Both centromeres and telomeres are heterochromatic, as is the Barr body of the second inactivated X chromosome in a female.

Answer 3

Heterochromatin is darkly staining because it is more condensed and more tightly packed than euchromatin. In general, heterochromatin is inactive in that it is not being transcribed into RNA. Euchromatin is the active part of chromatin, it is more lightly staining and is less tightly packed.

Chromatin is just the combination of DNA with large numbers of proteins. All eukaryotic chromosomes consist of chromatin.

Answer 4

highly condensed portions of the chromatin are called heterochromatin. Some of these portions remain permanently condensed so that their DNA is never expressed. The remainder of the chromosome called euchromatin is condensed only durin cell division, when compact packaging facilitates the movement of chromosomes. At all other times, euchromatin is present in open configuration and its genes can be expressed.

Answer 5

Euchromatin