1 - Question
Introduction of DNA molecules into the recipient organism is termed as ____________
Explanation: Introduction of DNA molecules into the recipient organism is termed as transformation. It is done with the help of endonucleases and ligases and the recipient organism is termed as host.
2 - Question
Many bacterial species are having a natural ability to take up the exogenous DNA material. Which of the statement is not correct in regard to it?
a) This ability is termed as competence
b) It is not limited to particular growth phases
c) The bacteria may develop new biochemical abilities under special conditions such as nutrient deprivation
d) Induction of specific set of bacterial proteins may take place
Explanation: This ability is termed as competence and it is limited to particular growth phases. It may lead to developing new biochemical abilities under special conditions such as nutrient deprivation. If the bacterial cells are naturally competent, they may take the foreign DNA by simply incubating them with foreign DNA.
3 - Question
Which of the statements hold true for conjugation?
a) Conjugation is the natural process of transferring DNA from one species to another
b) It is the artificial process in case the cells are not able to take them up naturally
c) The plasmids are transferred from one cell to another by physical contact
d) The plasmids are transferred from one cell to another by chemical means
Explanation: Conjugation is the process used for transferring plasmids from one cell to another in case they are not able to take up naturally. It is done via physical contact and the plasmid being transferred encodes the machinery.
4 - Question
F plasmid is often used in conjugation. The correct statement is?
a) The F plasmid encodes the factor which is transferred from one cell to another
b) The factor encoded by the F plasmid is called as Filamentous (F) factor
c) It is transferred from one cell to another by filament
d) The bacteria must belong to same species to carry out the conjugation
Explanation: F plasmid encodes the factor called Fertility or F factor. It is transferred from one cell to another by the sex pilus. It is present in E. coli and for the conjugation to take place; bacteria can also belong to different species.
5 - Question
Plasmids can be classified into how many types depending on the genes present for their transformation?
Explanation: Plasmids can be said as self-mobilizable and mobilizable. They are self mobilizable in the case they contain all the genes necessary to direct its own transfer. Mobilizable are those plasmids which don’t carry all the genes necessary for their transfer but they can be transferred if the genes are present somewhere in the host.
6 - Question
Viral infection can also be used to take up the DNA by the cells
Explanation: Viral infection can be used to take up the DNA by the cells. It is all because of the viral coat and the nucleic acid contained within has no role to play.
7 - Question
Chemical transformation refers to the methods which use chemicals in order to carry out transformation. Which of the following statements is true with respect to it?
a) Chemical transformation decreases the efficiency of transformation as compared to natural transformation
b) Ice cold calcium solution followed by heat shock is responsible for affecting the efficiency of DNA uptake
c) The mechanism responsible for it named as ‘the heat shock model’
d) Other complex mixtures such as those containing Manganese and hexamine cobalt can’t be used to affect the efficiency
Explanation: Chemical transformation methods increase the DNA uptake efficiency as in comparison to natural methods. The treatment by ice cold calcium solution which is followed by heat shock is responsible for increasing efficiency. But the exact mechanism behind it is not known till now. Other complex mixtures which comprise of cobalt, manganese etc. can be used to increase the efficiency.
8 - Question
Electroporation is also used for taking up the DNA by the cells. It constitutes of ____________
a) inserting the DNA into the cells via an electric shock
b) increased efficiency than both natural and chemical methods
c) causing the least amount of damage in comparison to other methods
d) decreased efficiency than both natural and chemical methods
Explanation: Electroporation is the method of DNA uptake via an electric shock. It is provided by varying the potential difference across the electrodes. It is having increased efficiency as compared to other methods. But also if prolonged treatment is given, it can cause destruction. It is so because the electric shock can be at times fatal to the cell wall.
9 - Question
Transformation carried out using a particle gun is known as biolistic transformation. It falls under which category of transformation?
Explanation: The transformation carried out using a particle gun falls under the physical transformation category. The physical transformation uses some physical methods in order to carry out the transformation.
10 - Question
The particle gun method consists of which of the following steps?
a) The DNA of interest is absorbed onto microprojectile beads
b) These beads are often made of aluminium
c) The explosion in a gun propels a macroprojectile forward which in turn propels microprojectile beads
d) The macroprojectiles and microprojectiles both cross the perforated plate and hit the target tissue behind it
Explanation: The DNA of interest is adsorbed on the microprojectile beads and these are made of gold and tungsten often. The explosion in the gun propels a macroprojectile forward and in turn propels microprojectile beads. These microprojectile beads cross the perforated plate but macroprojectiles don’t. The target tissue is behind the perforated plate and the microprojectiles hit it.