Gel electrophoresis is used for

1. cutting of DNA into fragments

2. separation of DNA fragments according to their size

3. construction of recombinant DNA by joining with cloning vectors

4. isolation of DNA molecule

The linking of antibiotic resistance gene with the plasmid vector became possible with

1. DNA ligase               

2. endonucleases

3. DNA polymerase       

4. exonucleases

Microbes found to be very useful in genetic engineering are:

1. Escherichia coli and Agrobacterium tumefaciens

2. Vibrio cholerae and a tailed bacteriophage

3. Diplococcus sp. and Pseudomonas sp.

4. Crown gall bacterium and Caenorhabditis elegans

Restriction endonuclease :

1. cuts the DNA molecule-randomly

2. cuts the DNA molecule at specific sites

3. restricts the synthesis of DNA inside the nucleus,

4. synthesizes DNA

Which of these are most widely used in genetic engineering?

1. Plastid

2. Plasmid

3. Mitochondrion

4. Ribosome

Introduction of  foreign genes for improving genotype is

1. biotechnology 

2. vernalization

3. tissue culture

4. genetic engineering

Restriction enzymes:

1. are endonucleases which cleave DNA at specific sites

2. make DNA complementary to an existing DNA or RNA

3. cut or join DNA fragments

4. are required in vectorless direct gene transfer

A tumor inducing plasmid widely used in the production of transgenic plants is that of

1. Escherichia coli

2. Bacillus thuringiensis

3. Staphylococcus aureus

4. Agrobacterium tumefaciens.

Electroporation procedure involves

1. fast passage of food through sieve pores in phloem elements with the help of electric stimulation

2. opening of stomatal pores during night by artificial light

3. making transient pores in the cell membrane to introduce gene constructs

4. purification of saline water with the help of a membrane system.

cDNA probes are copied from the messenger RNA molecules with the help of

1. restriction enzymes

2. reverse transcriptase

3. DNA polymerase

4. adenosine deaminase.