This set of Life Sciences Multiple Choice Questions & Answers (MCQs) focuses on “Bacterial Genome”.
1. Name the area of a bacterial cell which contains a bacterial chromosome.
d) Cell wall
Explanation: Nucleoid is the region of the bacterial cell which lacks a limiting membrane and contains the bacterial chromosome. BacteriaI circular dsDNA molecule is associated with polyamines instead of histone proteins.
2. Which of the following is not the nucleotide associated protein?
Explanation: Nucleoid associated proteins are of four types which facilitates compaction of chromosomal DNA by bending, bridging, and wrapping i.e. HU is heat unstable protein, H-NS is histone-like nucleoid structuring, IHF stands for integration host factor, and SMC is structural maintenance protein.
3. Which nucleoid protein assisted in condensation of DNA?
Explanation: H-NS protein helps in condensation of DNA by first binding with the DNA and then these proteins bind with each other and form an aggregate of four or more H-NS units.
4. All bacteria have single circular DNA molecule.
Explanation: Prokaryotes like E.coli has only one single circular DNA molecule composed of entire genome while rest contains multiple linear or circular DNA. Like, vibrio cholerae contains two circular chromosomes.
5. Name the group of bacteria which uses histone to condense DNA molecule?
Explanation: Archaebacteria is a group of prokaryotes which resembles eukaryotes in some aspect and differs from the bacterial group. Archaeans uses eukaryotes like histones to condense their DNA molecules.
6. Extrachromosomal DNA present in prokaryotes is called_______
a) Cocci group of bacteria
b) Chainlike group of bacteria
d) Grapelike cluster of bacteria
Explanation: Plasmids are extrachromosomal, autonomous, and self-replicating DNA molecule that maintains discrete genetic element in bacteria. Most plasmids are negatively supercoiled, circular dsDNA molecules but linear plasmids have also been reported.
7. Name the plasmid which makes host cell resistance to the antibiotic.
c) Col plasmid
Explanation: R plasmid stands for resistance plasmid which makes cell resistant to antibiotics. They have genes which code for enzymes that are capable of destroying or modifying antibiotics.
8. Which of the following is NOT the property of plasmid?
a) Rolling circle replication
b) Narrow host range
c) Two closely related plasmids cannot coexist in the same cell
d) Encodes gene products that are essential for growth
Explanation: Plasmids can have narrow as well as broad host range as when it exists only in a limited number of closely related bacteria, it shows narrow host range while if it transferred to and maintained in a large number of bacteria, it shows broad host range.
9. Name the type of plasmid which has no identified function or phenotypic properties?
a) Cryptic plasmid
c) High-frequency recombination
d) Col plasmid
Explanation: Cryptic plasmids do not code for genes that contribute any phenotypic properties or identified functions. They have no clear use for organisms in which they were identified.
10. Which of the following plasmid found in eukaryotes?
a) Col plasmid
b) 2μ circle
Explanation: Plasmids are found not only in prokaryotes but also in eukaryotes. Yeast plasmid is a 2μ circle, which is 6.3kb circular, extrachromosomal in nature and found in the nucleus of the yeast strain.
Sanfoundry Global Education & Learning Series – Life Sciences.
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