b. conversion of the beads on a string to the 30 nM fiber
Explanation:
Histone acetylation process adds an acetyl group to lysine amino acid in histone protein. Lysine is usually positively charged and thus is able to make strong bond with negatively charged DNA molecule. When acetyl group is added to lysine, its positive charge is removed. The bond between histone and DNA weakens and the whole structure becomes more open, loose and transcriptionally active.
Beads on a string is formed by wrapping of DNA around histone proteins. This structure further condenses into 30nm fiber leading to more compact and tightly packed chromatin structure. Since histone acetylation loosens up the chromatin, this process does not take place here.
The answer is the origin
of replication. This is where the replication bubble is formed. Two opposite replication
forks (Y-shaped regions) of DNA are formed when
the double helix is unzipped by DNA helicases. Transcription factors, polymerase III and primer then bind to the region
to begin transcription.
