Question

2.5 pts D Question 27 Which of the following statements is FALSE? o In Archaea there is only one turn of DNA around a nucleosome comprised of the histone H3-H4 tetramer Modifications of histone H3 tails at the K9 position can result in either repression or gene activation, depending of the type of modification. O There are 4 copies of each histone, including H1, in the eukaryotic nucleosome. Archaea have no histone tails since there are no higher orders of stable chromatin structure beyond the 10 nm fiber to regulate

Answer 1

27. Option 3 is false.

In the nucleosome of eukaryotic cells DNA is wraped around an octameric structure composed of 4 histone subunits.

There are 2 copies of each histone subunit named as: H2A, H2B, H3 and H4 . Two copies of each unit make an octameric structure and DNA would around this structure and then H1 unit comes and lock this structure by binding on it.

All histone units have tail except H1 so total eight tails are present in the octameric nucleosome structure.

Archea have hitones but not as that much developed and complex system as in eukaryotes.

All the remaining options are true.

28.

Option D is correct

These proteins are known as insulators.

These are transcriptional regulators which regulates the transcription or activation and inactivation of genes.

They flank heat shock protein genes which ultimately regulates various processes.

Basal factors: general transcription factor are also known as basal factors.

Shelterin complex: these are proteins which protects telomere in DNA repair step and regulates the activity of telomerase.

Balbiani puffing factors: structures formed on chromosome involved in various functions of regulation.