Q. No.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
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