FREE NEET Biology Practice MCQ Test: Biotechnology Principles And Processes Exercise 4 Questions Answers With Detailed Explanations [PDF]

Answer: (b)

Answer: (d)

Plasmid is a small circular double stranded DNA molecule present in the cytoplasm of the bacterial cell. It can replicate independently of bacterial chromosome. Due to this characteristic of plasmid, it is used as the vector (vectors are for the transferring of a piece of DNA to target gene) in gene cloning.

Answer: (b)

The enzyme used in PCR is Taq polymerase. Taq polymerase (isolated from bacterium thermus aquaticus) which remains active during the high temperature, usually amplifies DNA segments of upto 2 kb.

Answer: (a)

Interferons are antiviral proteins produced by recombinant DNA technology in E.coli.

Answer: (a)

Answer: (c)

Answer: (a)

The construction of the first recombinant DNA emerged from the possibility of linking a gene encoding antibiotic resistance with a native plasmid. The cutting of DNA at specific locations became possible with the discovery of the so called 'molecular scissors' – restriction enzymes. The cut piece of DNA was then linked with the plasmid DNA. This plasmid DNA acts as vector to transfer the piece of DNA attached to it. The linking of antibiotic resistance gene with the plasmid vector became possible with the enzyme DNA ligase, which acts on cut DNA molecules and joins their ends. This makes a new combination of circular autonomously replicating DNA created in vitro and is known as recombinant DNA.

Answer: (c)

DNA fragments migrate toward the positive end of the electrical field with the smallest fragments migrating the fastest.

Answer: (a)

Answer: (b)

Bacterial artificial chromosome (BAC) vectors are based on natural, extra-chromosomal plasmid of E. coli. BAC vector contains genes for replication and maintenance of the F-factor, a selectable marker and cloning site. These vectors can accommodate upto 300-350 kb of foreign DNA and are also being used in genome sequencing project. Yeast artificial chromosome (YAC) vectors are used to clone DNA fragments of more than 1Mb in size. Therefore, they have been exploited extensively in mapping the large genomes, e.g., in the Human Genome Project. These vectors contain the telomeric sequence, the centromere and the autonomously replicating sequence from yeast chromosomes.

Answer: (d)

A single strand DNA or RNA tagged with radioactive molecule that is used in of hybridization of DNA or RNA is called probe.

Answer: (c)

Answer: (d)

Answer: (d)

A stirred-tank bioreactors is usually cylindrical or with a curved base to facilitate the mixing of the reaction contents. The stirrer facilitates even mixing and oxygen availability throughout the bioreactor. Alternatively air can be bubbled through the reactor.

Answer: (b)

Answer: (d)

A stirred-tank bioreactor is usually cylindrical or with a curved base to facilitate the mixing of the reaction contents. The stirrer facilitates even mixing and oxygen availability throughout the bioreactor. Alternatively air can be bubbled through the reactor.

Answer: (d)

In gel electrophoresis, agarose extracted from seaweed is used as gel agarose which is made up of 0.7% gel which shows good resolution of large DNA and 2% gel will show good resolution of small fragments.

Answer: (a)

Answer: (a)

The separated DNA fragments can be seen only after staining them with a compound known as ethidium bromide (EtBr) followed by exposure to UV radiation as bright orange coloured bands.

Answer: (d)