In the screening process during rDNA experiments, clones that metabolize $\beta$-gal turn:

1. Colorless

2. Blue

3. Yellow

4. Green

The plasmid pBR322 does not contain:

1. An origin of replication site

2. A gene that encodes for restrictor of plasmid copy number

3. Gene for Ampicillin and Streptomycin resistance

4. Sites for many restriction enzymes

Restriction enzymes are synthesized by:

1. Bacteria only

2. Yeast and bacteria only

3. Eukaryotic cells only

4. All kinds of cells

The process of separation and purification of expressed protein before marketing is called

(1) upstream processing

(2) downstream processing

(3) bioprocessing

(4) postproduction processing

What is the criterion for DNA fragments movement on agarose gel during gel electrophoresis ?

(1) The larger the fragment size, the farther it moves

(2) The smaller the fragment size, the farther it moves

(3) Positively charged fragments move to farther end

(4) Negatively charged fragments do not move

A gene, whose expression helps to identify transformed cells is known as

1. selectable marker                 

2. vector

3. plasmid                                 

4. structural gene

The DNA fragments separated on an agarose gel can be visualised after staining with

(1) bromophenol blue

(2) acetocarmine

(3) aniline blue 

(4) ethidium bromide

Stirred-tank bioreactors have been designed for:

1. purification of product

2. addition of preservatives to the product

3. availability of oxygen throughout the process

4. ensuring anaerobic conditions in the culture vessel

A foreign DNA and plasmid cut by the same restriction endonuclease can be joined to form a recombinant plasmid using

(1) Eco RI                       

(2) taq polymerase

(3) polymerase III           

(4) ligase

Which of the following is not a component of downstream processing?

1. Separation

2. Purification

3. Preservation

4. Expression