Biochemistry Basics – 21505

Which statements are true about E. coli chromosomal DNA in relation with eukaryotic chromosomal DNA:

B. Packed into nucleolus

C. Negatively supercoiled

D. All of the above

Correct Answer » D Explanation

Long circular bacterial chromosomal DNA may be folded by an unknown mechanism to form a compact ring structure, in which the DNA segments are arranged according to their chromosome map positions
The bacterial chromosome, 1000 times the length of the bacterium, is folded by an unknown mechanism and organized in a compact form called the nucleoid.
The nucleoid is a closed duplex structure with a series of loops. The DNA loops are negatively supercoiled, resulting in further compaction. Moreover, several DNA-binding proteins, including HU, IHF, and H-NS, may promote a compact state of DNA in nucleoids.