Restriction endonucleases are enzymes which

1. make cuts at specific positions within the DNA molecule

2. recognize a specific nucleotide sequence for binding of DNA ligase

3. restrict the action of the enzyme DNA polymerase

4. remove nucleotides from the ends of the DNA molecule

Which one of the following is commonly used in transfer of foreign DNA into crop plants?

1. Trichoderma harzianum

2. Meloidogyne incognita

3. Agrobacterium tumefaciens

4. Penicillium expansum

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

Human insulin is being commercially produced from a transgenic species of

1. Escherichia

2. Mycobacterium

3. Rhizobium

4. Saccharomyces

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