Was bedeutet die DNA kondensiert sich?
Als Kondensation bzw. DNA-Kondensation bezeichnet man in der Genetik einen biochemischen Prozess, bei dem die DNA zu Chromatin bzw. Chromosomen verdichtet wird.
Warum wird die DNA verdichtet?
Während der Zellteilung (Mitose) wird die normalerweise lockere DNA so stark verdichtet, dass sich die Chromosomen mit Farbstoffen wie Fuchsin/Schweflige Säure spezifisch anfärben lassen. Aus dieser Eigenschaft heraus entstand auch der Name, der zunächst nichts anderes bedeutet als „anfärbbarer Zellbaustein“.
What is constitutive heterochromatin?
Constitutive heterochromatin is the stable form of heterochromatin, i.e. it does not loosen up to form euchromatin, and contains repeated sequences of DNA called satellite DNA. It can be found in centromeres and telomeres, and is usually involved in structural functions.
What is the difference between euchromatin and heterochromatin?
Chromatin is found in two varieties: euchromatin and heterochromatin. Originally, the two forms were distinguished cytologically by how intensely they get stained – the euchromatin is less intense, while heterochromatin stains intensely, indicating tighter packing. Heterochromatin is usually localized to the periphery of the nucleus.
What is euchromatin used for?
Euchromatin is available in transcriptionally active cells because of its accessibility to DNA, folding into heterochromatin to regulate the transcription by preventing the access of RNA polymerases and other regulatory proteins to the DNA. 2. What is Heterochromatin Used for?
What is an example of facultative heterochromatin?
Facultative heterochromatin. An example of facultative heterochromatin is X chromosome inactivation in female mammals: one X chromosome is packaged as facultative heterochromatin and silenced, while the other X chromosome is packaged as euchromatin and expressed.