1. Prokaryotic cells (only one correct answer)

a) Are unicellular, have a nucleus

b) Are multicellular, have a nucleoid

c) Have no DNA - just RNA

d) Are bacteria, have a circular DNA 

 

2. A complex of a DNA molecule and histone octamer is called?

a) Nucleosome

b) Nucleoplasm

c) Chromatid

d) Euchromatin

8. Which of the options below indicates the correct decreasing density of packing DNA?

a. DNA > Chromatin > Nucleosome > Chromosome b. DNA > Chromatin > Chromosome > Nucleosome c. DNA > Nucleosome > Chromatin > Chromosome d. Chromosome > Chromatin > Nucleosome > DNA e. Chromatin > Chromosome > Nucleosome > DNA
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Nucleosomes form the basis of chromatin structure. They are capable of being packaged tightly through the use of linker proteins, providing increasingly condensed chromatin. How might nucleosomes be arranged to increase chromatin compaction?

A. Binding of histone H1 to the nucleosome.

B. Binding of histone CENP-A to the nucleosome.

C. Incorporation of a histone - chromodomain protein complex into the nucleosome.

D. Incorporation of a histone - bromodomain protein complex into the nucleosome.

E. None of the above.

Duplex DNA composed entirely of CTG/CAG trinucleotide (5’-CTG in one strand and 5’-CAG in the other strand) is unusually flexible. If 75 CTG/CAG repeats are incorporated into a much longer DNA molecule and mixed with histone octamers, the first nucleosome that assembles nearly always includes the CTG/CAG repeat region. Suggest a reason why CTG/CAG repeats might be such effective elements for positioning nucleosomes? Consider what the energy of the binding interaction between histone octamers and the DNA must accomplish.