The Living World 8th Edition by George Johnson

تمرين 15

Eukaryotic chromosomes are composed of
A) DNA.
B) proteins.
C) histones.
D) All of the above.
Why does the DNA in a cell need to change periodically from a long, double-helix chromatin molecule into a tightly wound-up chromosome? What does it do in one configuration that it cannot do in the other?
What is a nucleosome?
A) a region in the cell's nucleus that contains euchromatin
B) a region of DNA wound around histone proteins
C) a region of a chromosome made up of multiple loops of chromatin
D) a 30-nm fiber found in chromatin