Which of the following statements is incorrect? [2024]
A bio-reactor provides optimal growth conditions for achieving the desired product.
Most commonly used bio-reactors are of stirring type.
Bio-reactors are used to produce small scale bacterial cultures.
Bio-reactors have an agitator system, an oxygen delivery system and foam control system.
(3)
In bioreactors, large volumes (100–1000 litres) of bacterial culture can be processed.
Thermostable DNA polymerase used in PCR was isolated from [2023]
Thermus aquaticus
Escherichia coli
Agrobacterium tumefaciens
Bacillus thuringiensis
(1)
In PCR, the repeated amplification is achieved by the use of a thermostable DNA polymerase enzyme Taq polymerase which is obtained from bacterium Thermus aquaticus. This enzyme remains active during the high temperature induced for denaturation of double stranded DNA.
During the purification process for recombinant DNA technology, addition of chilled ethanol precipitates out [2023]
histones
polysaccharides
RNA
DNA
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). [2022]
Assertion (A): Polymerase chain reaction is used in DNA amplification.
Reason (R): The ampicillin resistant gene is used as a selectable marker to check transformation.
In the light of the above statements, choose the correct answer from the options given below:
Both (A) and (R) are correct and (R) is the correct explanation of (A).
Both (A) and (R) are correct but (R) is not the correct explanation of (A).
(A) is correct but (R) is not correct.
(A) is not correct but (R) is correct.
Which of the following is a correct sequence of steps in a PCR (Polymerase Chain Reaction)? [2021]
Annealing, Denaturation, Extension
Denaturation, Annealing, Extension
Denaturation, Extension, Annealing
Extension, Denaturation, Annealing
(2)
A single PCR cycle involves three basic steps.
(i) Denaturation (DNA is heated to high temperature, usually 94°–96°C)
(ii) Primer annealing (two oligonucleotide primers anneal to each of the single stranded template DNA, temperature usually 40°–60°C) and
(iii) Extension (Taq DNA polymerase synthesises the DNA region between primers, optimum temperature 72°C).
During the purification process for recombinant DNA technology, addition of chilled ethanol precipitates out [2021]
polysaccharides
RNA
DNA
histones
Which of the following is not an application of PCR (Polymerase Chain Reaction)? [2021]
Detection of gene mutation
Molecular diagnosis
Gene amplification
Purification of isolated protein
(4)
Purification of isolated protein is one of the steps used in downstream processing of recombinant DNA technology.
During the process of gene amplification using PCR, if very high temperature is not maintained in the beginning, then which of the following steps of PCR will be affected first? [2021]
Ligation
Annealing
Extension
Denaturation
(4)
In PCR, the repeated amplification is achieved by the use of a thermostable DNA polymerase, which remains active during the high temperature induced denaturation of double stranded DNA. So, if high temperature is not maintained, denaturation will be affected first as it is carried out at a higher temperature 94° to 96°C.
Match the organism with its use in biotechnology: [2020]
(A) Bacillus thuringiensis — (i) Cloning vector
(B) Thermus aquaticus — (ii) Construction of first rDNA molecule
(C) Agrobacterium tumefaciens — (iii) DNA polymerase
(D) Salmonella typhimurium — (iv) Cry proteins
Select the correct option from the following.
A–(ii), B–(iv), C–(iii), D–(i)
A–(iv), B–(iii), C–(i), D–(ii)
A–(iii), B–(ii), C–(iv), D–(i)
A–(iii), B–(iv), C–(i), D–(ii)
DNA precipitation out of a mixture of biomolecules can be achieved by treatment with: [2019]
chilled chloroform
isopropanol
chilled ethanol
methanol at room temperature
(3)
In order to cut the DNA with restriction enzymes, it needs to be in pure form, free from other macromolecules. Since the DNA is enclosed by the membranes, we have to break the cell open to release DNA and other macromolecules like RNA, proteins, polysaccharides and lipids. It is obtained by treating the bacterial cells/plant or animal tissue with enzymes. Other molecules are removed by appropriate treatments and purified DNA ultimately precipitates out after the addition of chilled ethanol.
