AIIMS 2008
- Exam
- AIIMS
- Year
- 2008
- Subject
- Botany
- Chapter
- Biological Classification
AIIMS 2008 · Botany · Biological Classification
Thermococcus, Methanococcus and Methanobacterium exemplify
Thermococcus, Methanococcus and Methanobacterium exemplify
Options
- Abacteria whose DNA is relaxed or positively supercoiled but which have a cytoskeleton as well as mitochondria
- Bbacteria that contain a cytoskeleton and ribosomes
- Carchaebacteria that contains protein homologous to eukaryotic core histones
- Darchaebacteria that lack any histones resembling those found in eukaryotes but whose DNA is negatively supercoiled.
Correct answer
D. archaebacteria that lack any histones resembling those found in eukaryotes but whose DNA is negatively supercoiled.
Step-by-step solution
Thermococcus, Methanococcus and Methanobacterium 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.