How are transformants selected from nontransformants?

1. Presence of more than one recognition site in the vector DNA.

2. Presence of alien DNA into the vector DNA results into insertional inactivation of selectable marker.

3. Antibiotic resistance gene gets inactivated due to insertion of alien DNA.

4. Both 2 and 3.

Which of the following is not a characteristic of pBR322 vector? 

(1) It is the first artificial cloning vector constructed in 1977 by Boliver and Rodriguez.

(2) It is the most widely used, versatile and easily manipulated vector.

(3) It has two antibiotic resistance genes, tet^R and amp^R.

(4) It does not have restriction site for Sal I.

Plasmid vector in DNA recombinant technology means

1. a virus that transfers gene to bacteria

2. extra-chromosomal autonomously replicating circular DNA

3. sticky end of DNA

4. any fragment of DNA carrying desirable gene

Biolistic (gene gun) is suitable for

1. disarming pathogen vectors

2. transformation of plant cell

3. constructing recombinant DNA by joining with vectors

4. DNA fingerprinting

Which of the following DNA sequences qualifies to be designated as a palindrome?

(1) 5 - GACCAG - 3’ in one strand

(2) 3’- GACCAG - 5’ in one strand

(3) 5’- GACGAG- 3’ 3’- CTGGTC - 5’

(4) 5’- AGCGCT - 3’ 3’- TCGCGA - 5’

The source of taq polymerase used in PCR is a

(1) thermophilic fungus

(2) mesophilic fungus

(3) thermophilic bacterium

(4) halophilic bacterium

Which of the following statement is not true: 

(1) Transformation is a procedure through which a piece of DNA is introduced in a host bacterium

(2) Normally, the genes encoding resistance to antibiotics are considered useful selectable markers for E.coli

(3)  The normal E.coli cells do not carry resistance against antibiotics such as ampicillin, chloramphenicol, tetracycline or kanamycin

(4) Presence of one recognition sites within the vector will generate several fragments, which will complicate the gene cloning

To be useful in genetic engineering a vector must have

1. An origin for replication
2. Low copy number
3. Low rates of multiplication
4. Many cloning sites for the same enzyme

In 1960’s two enzymes were discovered in bacteria that were responsible for providing immunity against bacteriophages. One was Restriction Endonuclease and the other was

1. Methylase

2. Exonuclease

3. Aminotransferase

4. Terminal Transferase

 E.coli is  a commonly used host for gene cloning because

1. It is free from elements that interfere with replication and recombination of DNA

2. It is easy to transform

3. It supports replication of inserted DNA.

4. All of these