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

Which of the following is not correctly matched for the organism and its cell wall

degrading enzyme?

1. Bacteria —Lysozyme

2. Plant cells — Cellulase

3. Algae —Methylase

4. Fungi — Chitinase

In order to make the host cell competent

Divalent cations such as calcium are used-

1.      The divalent ions have to be in a specific concentration

2.      They cause the DNA uptake by the cell

3.      They increase the efficiency with which DNA enters the bacterium through pores in its cell wall.

4.     All of the above

Which of the following step is last for isolating the desired DNA fragment?

1.      Running of gel

2.      Elution

3.      Staining

4.     Visualization

What does cloning mean?

1.      The ability to multiply the desired gene in the host

2.      The ability to multiply the vector in the host

3.      The ability to multiply the antibiotic resistance gene in the host

4.     The ability to multiple Ori in the host

Consider the following statements:

Which of the above statements are true?

A host cell normally does not take up a foreign DNA until it has been made competent to do so. This is because:

1. DNA is a hydrophilic molecule

2. DNA is a very large molecule

3. there are no receptors for DNA on the cell membrane

4. DNA is an inert molecule

The process of competent cell formation include

1.      CaCl2 treatment- ice incubation with r-DNA, heat shock at 42 degree Celsius, ice incubation

2.      Ice incubation - CaCl2 treatment - Heat shock-Ice incubation with r-DNA

3.      CaCl2 treatment - Heat shock -Ice incubation with r-DNA

4.     Ice incubation - CaCl2 treatment - Heat treatment at 45 degree Celsius, Ice incubation with r-DNA

Elution is:

1. Separating the restricted DNA fragments on agarose gel.

2. Staining the separate DNA fragments with ethidium bromide

3. cutting out of the separated band of DNA from the agarose gel and extracting them from the gel piece.

4. constructing rDNA by joining the purified DNA fragments to the cloning vector.

When isolating the pure DNA from a bacterial cell, the cell should not be treated with:

1. lysozyme

2. proteases

3. ribonuclease

4. deoxyribonuclease