Chromosomes seen in metaphase of mitosis are the ‘highest order’, most condensed form of chromatin. The 10 nm filament of nucleosome ‘beads-on-a-string’ remaining after a low salt extraction can be seen in an electron microscope as shown below.
What is the most condensed state of chromatin?
Heterochromatin is more condensed than euchromatin. Typically, the more condensed chromatin is, the less accessible it is by transcription factors and polymerases. The dynamic nature of chromatin is regulated by enzymes.
What is the condensed form of chromatin?
Chromatin exists in two forms. One form, called euchromatin, is less condensed and can be transcribed. The second form, called heterochromatin, is highly condensed and is typically not transcribed. Under the microscope in its extended form, chromatin looks like beads on a string.
Is heterochromatin or euchromatin more condensed?
Euchromatin has a less compact structure, whereas heterochromatin is more compact and composed of an array of nucleosomes condensed into a fiber. These levels of chromatin compaction are illustrated here in two chromosomes (orange and blue).
What is the most highly condensed form of interphase chromatin?
In contrast to euchromatin, about 10% of interphase chromatin (called heterochromatin) is in a very highly condensed state that resembles the chromatin of cells undergoing mitosis.
Why are chromosome condensed?
Chromatin, a substance that contains genetic material such as DNA, is normally found in a loose bundle inside a cell’s nucleus. During the prophase of mitosis, the chromatin in a cell compacts to form condensed chromosomes; this condensation is required in order for the cell to divide properly.
Why chromosomes are condensed Mcq?
Why are chromosomes condensed? Explanation: As the cells enter mitosis, there chromosomes become highly condensed so that they can be distributed to daughter cells.
What is the more darkly staining form of chromatin?
The more darkly-staining form of chromatin is heterochromatin. Since heterochromatin is very condense, it stains more easily than euchromatin.
Is the lightly condensed region of the chromatin network?
Euchromatin is the lightly packed form of chromatin, whereas heterochromatin refers to the condensed form.
What does acetylation of histones do?
Acetylation of histones alters accessibility of chromatin and allows DNA binding proteins to interact with exposed sites to activate gene transcription and downstream cellular functions.
What is chromatin differentiate between euchromatin and heterochromatin?
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.
What is chromatin heterochromatin and euchromatin?
Heterochromatin and euchromatin are two major categories of chromatin higher order structure. Heterochromatin has condensed chromatin structure and is inactive for transcription, while euchromatin has loose chromatin structure and active for transcription.
What is Heteropycnosis?
Heteropycnosis is a phenomenon shown by chromosomes in which certain regions of chromosomes stain more intensely than others.
What is Euchromatic nucleus?
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. … In eukaryotes, euchromatin comprises the most active portion of the genome within the cell nucleus.
How do Condesins condense chromatin?
Chromatin condensation is driven by condensins and interactions between histones. … Although already significantly compacted during interphase, upon entry into mitosis chromatin further condenses and individualizes to discrete chromosomes that are captured and moved independently by the mitotic spindle apparatus.
What is the major type of chromatin in the nucleus during interphase?
The predominant type of chromatin found in cells during interphase, euchromatin is more diffuse than the other kind of chromatin, which is termed heterochromatin.