Processes of recombinant DNA technology
- Given below are two statements :Statement I : The DNA fragments extracted from gel electrophoresis can be used in construction of recombinant DNA.Statement II : Smaller size DNA fragments are observed near anode while larger fragments are found near… Answer: 1. Both statement I and statement II are correct Key idea: Gel electrophoresis separates DNA by size, and the separated bands can be... 1
- Identify the part of a bio-reactor which is used as a foam braker from the given figure. Answer: 4. C Key idea: In a stirred-tank bioreactor the foam breaker is a blade on the shaft near the top, in the headspace above the cultur... 1
- Polymerase chain reaction (PCR) amplifies DNA following the equation. Answer: 2. 2ⁿ Key idea: In each PCR cycle every DNA molecule is copied once, so the number of copies doubles. Starting from one DNA molecule... 1
- Which of the following statements is incorrect? Answer: 4. Bio-reactors are used to produce small scale bacterial cultures. Bioreactors are large vessels (hundreds to thousands of litres)... 1
- What is the fate of a piece of DNA carrying only gene of interest which is transferred into an alien organism?A. The piece of DNA would be able to multiply itself independently in the progeny cells of the organism.B. It may get integrated into the ge… Answer: 4. B and C only Key idea: a piece of alien DNA without an origin of replication cannot multiply on its own. It either integrates int... 1
- In gene gun method used to introduce alien DNA into host cells, microparticles of ________ metal are used. Answer: 4. Tungsten or gold Key idea: In the biolistic (gene gun) method, DNA is coated on microscopic particles of tungsten or gold, which... 1
- Main steps in the formation of Recombinant DNA are given below. Arrange these steps in a correct sequence.A. Insertion of recombinant DNA into the host cell.B. Cutting of DNA at specific location by restriction enzyme.C. Isolation of desired DNA frag… Answer: 2. B, C, D, A or 4. C, B, D, A Key idea: A recombinant DNA is made by cutting the DNA, getting the desired fragment, amplifying it,... 1
- Upon exposure to UV radiation, DNA stained with ethidium bromide will show Answer: 1. Bright orange colour Key idea: DNA stained with ethidium bromide and exposed to UV light fluoresces as bright orange bands. This... 1
- Which one of the following statement is not true regarding gel electrophoresis technique ? Answer: 4. The presence of chromogenic substrate gives blue coloured DNA bands on the gel. In gel electrophoresis, DNA fragments are stained... 1
- Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).Assertion (A) :Polymerase chain reaction is used in DNA amplificationReason (R) :The ampicillin resistant gene is used as a selectable marker to… Answer: 3. Both (A) and (R) are correct but (R) is not the correct explanation of (A) Check each statement and then the link between them. A... 1
- For effective treatment of the disease, early diagnosis and understanding its pathophysiology is very important. Which of the following molecular diagnostic techniques is very useful for early detection ? Answer: 3. ELISA Technique ELISA detects antigens or antibodies and can reveal infection (e.g. HIV) before symptoms appear, so it is the tec... 1
- 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 ? Answer: 3. Denaturation PCR starts with denaturation at about 94°C, which separates the double-stranded DNA into single strands. Without thi... 1
- Now a days it is possible to detect the mutated gene causing cancer by allowing radioactive probe to hybridise its complimentary DNA in a clone of cells, followed by its detection using autoradiography because : Answer: 3. mutated gene does not appear on a photographic film as the probe has no complimentarity with it. The radioactive probe is a singl... 1
- Which of the following is not an application of PCR (Polymerase Chain Reaction) ? Answer: 3. Purification of isolated protein PCR amplifies a chosen DNA segment from small amounts of DNA. It is used for gene amplification,... 1
- During the purification process for recombinant DNA technology, addition of chilled ethanol precipitates out : Answer: 2. DNA DNA is insoluble in ethanol. When chilled ethanol is added to the purified lysate, DNA precipitates and appears as fine threa... 1
- Which of the following is a correct sequence of steps in a PCR (Polymerase Chain Reaction) ? Answer: 1. Denaturation, Annealing, Extension Each PCR cycle has three steps in order: denaturation (double strand separated at about 94 °C)... 1
- In gel electrophoresis, separated DNA fragments can be visualized with the help of : Answer: 2. Ethidium bromide in UV radiation Key idea: DNA in agarose gels is stained with ethidium bromide and viewed under UV light. Ethidi... 1
- DNA precipitation out of a mixture of biomolecules can be achieved by treatment with : Answer: 2. Chilled ethanol DNA is precipitated by adding chilled ethanol, and it then appears as fine threads that can be spooled out. Optio... 1
- Which one of the following equipments is essentially required for growing microbes on a large scale, for industrial production of enzymes ? Answer: 4. Bioreactor Large-scale culture of microbes for products such as enzymes needs a bioreactor, which gives controlled temperature, p... 1
- The correct order of steps in Polymerase Chain Reaction (PCR) is Answer: 4. Denaturation, Annealing, Extension PCR is a cycle of three steps in a fixed order: denaturation, annealing, extension. Heat (abou... 1
- What is the criterion for DNA fragments movement on agarose gel during gel electrophoresis ? Answer: 1. The smaller the fragment size, the farther it moves Key idea: The gel acts as a sieve. All DNA fragments are negatively charged a... 1
- DNA fragments are : Answer: 1. Negatively charged Key idea: DNA has a phosphate group on each nucleotide. The phosphate groups carry a negative charge, so every... 1
- The process of separation and purification of expressed protein before marketing is called : Answer: 1. Downstream processing Key idea: Making a product has two stages. Upstream processing covers growing the cells in a bioreactor. Do... 1
- The DNA fragments separated on an agarose gel can be visualised after staining with : Answer: 3. Ethidium bromide Key idea: DNA bands on agarose are seen with a dye that binds DNA and fluoresces. Ethidium bromide intercalates... 1