What is true for the plasmids used as cloning vectors in recombinant procedures?
1. | Ori is responsible for controlling the copy number of linked DNA |
2. | The bacteria lacking R plasmids are resistant to antibiotics |
3. | The vector must have many sites for the same restriction enzyme |
4. | They can carry largest inserts amongst the available cloning vectors |
The enzyme used in the polymerase chain reaction is a:
1. DNA dependent RNA polymerase
2. RNA dependent DNA polymerase
3. DNA dependent DNA polymerase
4. RNA dependent RNA polymerase
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 |
How does the bacterium protects its own DNA from the action of restriction endonucleases present in its cytoplasm?
1. | its DNA lacks active sites for the restriction endonucleases |
2. | its DNA is protected within a nuclear envelope |
3. | it adds methyl groups to the active sites of restriction endonucleases on its DNA |
4. | the DNA gets heterochromatised to prevent the action of restriction enzymes |
When “sticky ends” are paired, they can be joined by:
1. | restriction enzymes | 2. | polymerases |
3. | methylase | 4. | DNA ligase |
Which of the following is normally not used as a method of introduction of foreign DNA into an animal cell?
1. | Microinjection | 2. | Liposomes |
3. | Biolistics | 4. | Transfection |
Which of the given statements is correct in the context of visualizing DNA molecules separated by agarose gel electrophoresis?
1. | DNA can be seen in visible light |
2. | DNA can be seen without staining in visible light |
3. | Ethidium bromide stained DNA can be seen in visible light |
4. | Ethidium bromide stained DNA can be seen under exposure to UV light |
'Restriction' in Restriction enzyme refers to:
1. | Cleaving of the phosphodiester bonds in DNA by the enzyme |
2. | Cutting of DNA at a specific position only |
3. | Prevention of the multiplication of bacteriophage by the host bacteria |
4. | All of the above |
The most important feature in a plasmid to serve as a vector in gene cloning experiment is:
1. Origin of replication (ori)
2. Presence of a selectable marker
3. Presence of sites for restriction endonuclease
4. Its size
Which of the following steps are catalysed by Taq DNA polymerase in a PCR reaction?
1. Denaturation of template DNA
2. Annealing of primers to template DNA
3. Extension of primer end on the template DNA
4. All of the above