Thermococcus, Methanococcus and Methanobacterium exemplify:

Options

A. bacteria whose DNA is relaxed or positively supercoiled but which have a cytoskeleton as well as mitochondria
B. bacteria that contains protein homologous to eukaytic core histones
C. archaebateria that contains protein homologus to ekaryotic core histones
D. archaenacteria that lack any histones resembing those found in eukaryotes but whose DNA is negatively supercoiled.

Answer

D

Explanation

Thermococcus, Methanococcus and Methanobucterium exemplify archaebacteria that lack any histones resembling those found in eukaryotes but whose DNA is negatively supercoiled. Archaebacteria do not have a nucleus, the genetic material floats freely in the cytoplasm. They consist of ribosomal RNA. DNA contains a single, circular molecule, which is compact and tightly wound. No protein is associated with DNA. The archaebacterial cell may contain plasmids, which are small, circular pieces of DNA and have a highly negatively supercoiled DNA.