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Gene cloning - class-XII

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Genetic engineering is possible because 

  1. DNA can be cut at specific sites by endo nucleases like DNAase

  2. Restriction endonucleases purified from bacteria can be used in vitro

  3. The phenomenon of transduction in bacteria is well understood

  4. DNA can be seen by electron microscope


Correct Option: A
Explanation:

Genetic engineering is the technique by which the genetic material of an organism is manipulated. The desired genes from any organism are isolated and are transferred into the organism where those genes are expressed and desired products are obtained. Manipulation of an organism's genome is not a simple process and involves a number of tools including restriction enzymes. 

Restriction enzymes are the most important tools in genetic engineering. They make cuts in the DNA at specific positions. They may be exonuclease if they make cut at the end of DNA or endonuclease if they make cut within the DNA. Restriction endonucleases cut the DNA into fragments like DNAsse. The fragments of DNA are then jouned by DNA ligases. 

So, the correct answer is 'DNA can be cut at specific sites by endo nucleases like DNAase'.

In recombinant DNA technology, a plasmid vector is cleaved by

  1. Modified DNA ligase

  2. A heated allkaline solution

  3. The same enzyme that cleaves the donor DNA

  4. The different enzyme than that cleaves the donor DNA


Correct Option: C
Explanation:

Answer is option C i.e. "The same enzyme that cleaves the donor DNA"
In rDNA technology, the plasmid vector must be cleaved by specific restriction enzyme. Plasmid vectors are cleaved by  same enzyme that cleaves the donor DNA leading to creation of sticky ends which further helps in recombination.

Which of the following is not a tool of genetic engineering?

  1. Cloning vector

  2. Restriction enzyme

  3. Foreign DNA

  4. GMO.


Correct Option: D
Explanation:

Answer is option D i.e. "GMO"
GMO are genetically modified organism. GMOs are every plant, animal, or microorganism that is transformed by genetic engineering. Tools of genetic engineering are the requirements to carry in-vitro genetic engineering process, this involves the use of laboratory tools to insert, alter, or cut out pieces of foreign DNA with help of restriction enzyme and cloning them through vector in respective host cell.

Genetic engineering aims at

  1. Destroying wild gene

  2. Preserving defective gene

  3. Curing human disease by introducing new gene

  4. All of the above


Correct Option: C
Explanation:

The non-mutated normal form of a gene which is naturally present in population is called as wild type allele. They impart natural genotype and natural phenotypes/traits to the organisms which is not a target for genetic engineering. Defective genes are the one that code for non-working or malfunctioning polypeptide and, thus, adversely affect the organisms. These genes should be eliminated, not preserved, from genome to fix the defects caused by them. Gene therapy is the process of introduction of DNA into living human beings in order to treat disease. It is used to replace a missing gene product or to correct mutant alleles. Gene therapy is a type of genetic engineering.

Maintenance of sterile ambience to enable growth of only desired cell in large quantities for manufacture of biotechnological product is

  1. Bio process engineering

  2. genetic engineering

  3. One of the core technique of modern biotechnology

  4. More than one options correct


Correct Option: D
Explanation:

  • Bioprocess engineering is a type of chemical engineering, it is responsible for the development of materials that are used in biotechnology like food, chemicals, tools etc.
  • Genetic engineering also involves chemical as well as biological engineering, This technique involves the manipulation of DNA, its constituents to make a desirable DNA.
  • Maintenance of ambiance means to maintain a microbial or disease-free culture for the process of biotechnological techniques so that only the desired gene or cell is amplified (multiplication of gene to form a large number of copies).
So, the correct option is 'Bioprocess engineering and Genetic engineering'

Which among the following genetically engineered microorganisms is used successfully in bioremediation of oil spills?

  1. Pseudomonas

  2. Trichoderma

  3. Xanthomonas

  4. Bacillus


Correct Option: A
Explanation:

Xanthomonas is used for bioproduction of xanthan gum which is a polysaccharide and is used as a food additive. Bacillus thuringiensis (Bt) produces Bt toxin during sporulation. The toxin bind to receptors on midgut epithelial cells of gallworm, become inserted into the plasma membrane where they form pores leading to cell death through osmotic lysis; thus serving as biopesticide. Trichoderma serve as very effective biocontrolling agent for soil borne plant disease management. It is a free-living fungus, and reduces pathogenic infections by different mechanisms like competition, antibiosis, hyphal interactions, mycoparasitism, , and enzyme secretion. Pseudomonas putida is used in bioremediation owing to its aerobic metabolism with ability to degrade organic pollutants such as toluene and to convert styrene oil to biodegradable plastic Polyhydroxyalkanoates (PHA). Correct answer is A.

Introduction of food plants developed by genetic engineering is not desirable because

  1. Economy of developing countries may suffer.

  2. These products are less tasty as compared to the already existing products.

  3. This method is costly.

  4. There is danger of coming viruses and toxins with introduced crop.


Correct Option: D
Explanation:

Gene synthesis is process to synthesize gene; the gene, for which nucleotide sequence is known, can be synthesized chemically and the genes for which sequencing has not been done, are synthesized by RNA dependent DNA polymerase. The synthesized gene is inserted into genome of selected crop plants which in turn produce the desired protein product; once cloned, genetically engineered crops are economic method of production modified crop plants. GM products are not tasteless; gene for additional taste can be cloned. To achieve desired level of protein products; introduced gene is expressed at higher level which in turn may introduce the antigens/toxins or even viruses in human. Presence of foreign DNA /gene or gene products in crop plants is sensed by immune system of human and can initiate allergic or immune responses in them. Correct option is D.

Biologically functional gene coding for tyrosine tRNA of E.coil, synthesized by Khorana in 1979, had

  1. 333 nucleotide pairs

  2. 312 nucleotide pairs

  3. 77 nucleotide pairs

  4. 207 nucleotide pairs


Correct Option: D
Explanation:

H. G. Khorana and co-workers synthesized the gene for $E$.$coli$ tyrosine tRNA precursor. The tyrosine tRNA precursor has 126 nucleotides. A complete sequence of dsDNA coding for tyrosine tRNA precursor of E. coli was synthesized. Twenty six small oligonucleotide DNA segments that produced a complete tRNA precursor were synthesized. These oligonucleotides were then arranged into six dsDNA segments. Each ds DNA segment had single stranded ends to facilitate their joining to produce complete gene of 126 base pairs for tyrosine tRNA precursor of E. coli. He then synthesized biologically functional gene coding for tyrosine t-RNA of E.coil. It was 207 base pairs long with 51 bp long promoter region, a 126 bp long precursor region of tRNA, a 25 bp long DNA in which 16 base pairs contained restriction site for EcoRI. Option D is the correct answer.

Which one of the following has found extensive use in genetic engineering work in plants?

  1. Bacillus coagulans

  2. Agrobacterium tumefaciens 

  3. Clostridium septicum

  4. Clostridium botulinum


Correct Option: B
Explanation:

Agrobacterium tumefaciens is a soil plant pathogenic bacterium that carries Ti plasmid. It can transfer a particular segment of the tumor-inducing (Ti) plasmid into the nucleus of infected cells. The transferred T-DNA is then integrated into the host genome and transcribed with it. This ability of Agrobacterium tumefaciens to transfer the T-DNA in host genome is explored in genetic engineering to transfer the desired DNA segment, carrying the gene of the interest, into genome of selected organisms. Bacillus coagulans is a lactic-acid producing, endospore forming soil bacteria that is used as probiotics. Clostridium septicum is gram positive, spore forming, obligate anaerobic bacteria that cause gas gangrene and is associated with malignancy. 

In genetic engineering a chimera is?

  1. An enzyme that links DNA molecules

  2. A plasmid that contains foreign DNA

  3. A virus that infects bacteria

  4. A fungi


Correct Option: A

Name the transgenic crop in which three genes for synthesis of vitamin A are introduced through the technique of genetic engineering.

  1. Kalyan Sona wheat

  2. Sweet sorghum

  3. Hybrid bajra

  4. Golden rice


Correct Option: D

In genetic engineering, which of the following is used?

  1. Plasmid

  2. Plastid

  3. Mitochondria

  4. Endoplasmic reticulum


Correct Option: A
Explanation:

Genetic engineering mainly aims at the transfer of genes of desired protein products between the organisms. Plastids are double membrane bound organelles that serve as the site for photosynthesis. Mitochondria are double membrane bound eukaryotic cell organelles that serve as the site for cellular respiration, produce an enormous amount of energy. ER is eukaryotic organelle with a network of tubules, vesicles, and cisternae within the cells. It serves to synthesis and transport of proteins and lipids. Plasmids are low molecular weight extrachromosomal DNA that carries origin of replication, restriction sites and selectable markers to confer readily selectable phenotypic traits on host cells. Plasmids require very few genes for their own replication and rest of it can be deleted and foreign sequences can be added to the plasmid which in turn makes them a suitable candidate to serve as a vector for gene transfer. Thus, the correct answer is option A.

Which of the following bacteria are used in study of 'genetics'?

  1. E. coli

  2. Bacillus

  3. Pseudomonas

  4. Rhizobium


Correct Option: A
Explanation:
E. coli is the most well-understood bacterium and is an extremely important model organism in many fields of research, particularly molecular biology, genetics, and biochemistry. It is easy to grow under laboratory conditions, and research strains are very safe to work with. As with many bacteria, E. coli grows quickly, which allows many generations to be studied in a short time. Under ideal conditions, E. coli cells can double in number after only 20 minutes. The genetics of E. coli are well-understood and can be readily manipulated.
Therefore, the correct answer is option A.

Which of the following is related with genetic engineering?

  1. Golgi apparatus

  2. Lysosomes

  3. Mitochondria

  4. Plasmid


Correct Option: D
Explanation:

Genetic engineering mainly aims at the transfer of genes of desired protein products between the organisms. Lysosomes are the suicidal bags of cell that digest and remove the wear and tear organelles and molecules from the cell. Golgi body consist of flattened sacs stacked on each other, that serve to processes secretory and synthetic products from the ER and then transport the finished products into cell part or secretes them to the outside of the cell. Mitochondria are double membrane bound eukaryotic cell organelles that serve as the site for cellular respiration, produce an enormous amount of energy and therefore are also known as a power house of cell. Plasmids are low molecular weight extrachromosomal DNA that carries origin of replication, restriction sites and selectable markers to confer readily selectable phenotypic traits on host cells. Plasmids require very few genes for their own replication and rest of it can be deleted and foreign sequences can be added to the plasmid which in turn makes them a suitable candidate to serve as a vector for gene transfer. Thus, the correct answer is option C.

What is the trade name of genetically engineered insulin?

  1. Anulin

  2. Beta insulin

  3. Humilin

  4. Gilbert's insulin


Correct Option: C
Explanation:

Genetically engineered insulin is sold with commercial name 'humulin'.

Radiology deals with the study of

  1. UV rays

  2. Gamma rays

  3. Cosmic rays

  4. X-rays


Correct Option: D
Explanation:

Radiology is a medical specialty that uses imaging to diagnose and treat disease seen within the body. Radiologists use a variety of imaging techniques such as X-ray radiography, ultrasound, computed tomography (CT), nuclear medicine, positron emission tomography (PET) and magnetic resonance imaging (MRI) to diagnose or treat diseases. 

Which is considered a superior method for identification of urine sugars?

  1. Endoscopy

  2. Thin layer chromatography

  3. Electrocardiogram

  4. Tomography


Correct Option: B
Explanation:
  • Thin-layer chromatography is a method that is used for the separation and identification of the amino acids and sugars. 
  • There are different substances that may be present in the urine which is excreted by an organism. 
  • Generally, the amount of sugar that is excreted by humans is less. 
  • In the case of diabetic patients, the sugar in the urine can be detected by this method of chromatography in which there is a thin layer of silica gel and the solvent is used with respect to the sugars. 
  • The solvent flows and allows the separation of the different molecules.
  • Thus, the correct answer is option B. 

Terminator seeds produced by giant seed companies using techniques of genetic engineering are in fact _________________.

  1. Hybrid seeds which germinate in the frame's field but do not produce seeds in the next generation

  2. Hybrid seeds which give a very high yield

  3. Seed which germinate and produce incompatible gametes

  4. Seeds that develop into fertile plants which produce flog-terminable seeds


Correct Option: A

Which one is being produced by genetically altered genes _________________.

  1. Calcitonin

  2. Platelet derived growth factor

  3. Erythropoietin

  4. All the above


Correct Option: D

Protein $\alpha$-1 antitrypsin is used to treat

  1. Cancer

  2. Rheumatoid arthritis

  3. Alzheimers disease

  4. Emphysema

  5. ADA deficiency disease in children


Correct Option: D

Transgenic hirudin is obtained from

  1. Ocimum sanctum

  2. Brassica napus

  3. Potato

  4. Tomato


Correct Option: B
Explanation:

Transgenic hirudin is obtained from Brassica napus.

Ti plasmid used in genetic engineering is obtained from _________________.

  1. Bacillus thuzingiensis

  2. Agrobacterium rhizogenes

  3. Agrobacterium tumefaciens

  4. Pseudomonas syringae


Correct Option: A

Which of the following statements is/are correct? 

  1. The current interest in the manipulation of microbes, plants and animals has raised serious ethical issues.

  2. One possible risk of genetic engineering is the accidental production of antibiotic resistant microorganisms.

  3. Although risks are possible, genetic engineering offers more of a contribution to human welfare than threats.

  4. All of these.


Correct Option: D
Explanation:

  • Several animal studies indicate serious health risks associated with genetically modified (GM) food including infertility, immune problems, accelerated aging, faulty insulin regulation, and changes in major organs and the gastrointestinal system.
  • One of the first cases of human benefit from genetic engineering was the production of human insulin in bacterial cells. Previous to this, diabetic patients were treated with pig insulin. Use of bacterially-derived human insulin has substantially reduced the number of animals used to produce insulin and also significantly reduces adverse reactions in diabetic patients as the molecule is identical to human insulin. Since the successful production of genetically engineered insulin, many other human proteins have been produced in this manner. This technology has improved millions of lives.

So, the correct option is 'All of these.'.

In genetic engineering, a DNA segment (gene) of interest, is transferred to the host cell through a vector. Consider the following four agents (i-iv) in this regard and select the correct option about which one or more of these can be used as a vector/ vectors.
(i) Bacterium (ii) Plasmid (iii) Plasmodium (iv) Bacteriophage

  1. (i), (ii) and (iv)

  2. (i) only

  3. (i) and (iii)

  4. (ii) and (iv)


Correct Option: A

Manipulation of DNA to change its structure is called genetic engineering.

  1. True

  2. False


Correct Option: A
Explanation:

Genetic engineering is a technique to alter the chemistry of genetic material (DNA and RNA), to introduce these into the host organisms and thus change the phenotype and genetic makeup of the organism.

So, the statement is 'True'.

Research projects: 

  1. cloning

  2. identical/ non identical twins

  3. triplets/ quadruplets

  4. surrogacy

  5. IVF


Correct Option: A
Explanation:

Cloning is the process of generating a genetically identical copy of a cell or an organism. Cloning happens all the time in nature for example, when a cell replicates itself asexually without any genetic alteration or recombination.

So, the correct option is 'Cloning'.

Genetic engineering has been successfuly used for producing

  1. Transgenic cow named Rosie which produces high fat milk for making ghee.

  2. Animals like bulls for farm work as they have super power.

  3. Transgenic mice for testing safety of polio vaccine before use in humans.

  4. Transgenic models for studying new treatments for certain cardiac diseases.


Correct Option: C,D
Explanation:

The first transgenic cow, Rosie was engineered for production of human protein-enriched more nutritional balanced milk (2.4 grams per litre). Rosie’s milk contains the human gene $\alpha$-lactalbumin; which makes statement A incorrect. Transgenic bull was produced for lactoferrin in their milk which has antimicrobial activity and is components of innate defence; statement B is incorrect. Animal rabbit models have been used to study pathophysiology and treatment of cardiovascular diseases which makes statement D correct. Transgenic mice for testing safety of polio vaccine before use in human; for the purpose, they are subject to GSK test which measures the safety of the vaccine; statement C is correct.

Transfer of any gene into a completely different organism can be done through 

  1. Genetic engineering

  2. Tissue culture

  3. Transformation

  4. RNA interference


Correct Option: A

Plasmids are

  1. Viruses

  2. Extra-chromosomal genetic element of bacteria

  3. New type of microorganism

  4. Genetic element of bacteria


Correct Option: B
Explanation:

A plasmid is a small DNA molecule within a cell that is physically separated from a chromosomal DNA and can replicate independently. They are most commonly found in bacteria as small, circular, double-stranded DNA molecules. Plasmids carry only a few genes and exist independently of chromosomes, the primary structures that contain DNA in cells. Able to self-replicate, plasmids can be picked up from the environment and transferred between bacteria. Plasmids are used by their host organism to cope with stress-related conditions.

Therefore, the correct answer is option B.

Introduction of one or more genes into an organism which are normally not possessed by them or their deletion by using artificial means (not by breeding) comes under 

  1. Molecular biology

  2. Genetic hybridisation

  3. Cytogenetics

  4. Genetic engineering


Correct Option: D
Explanation:

Genetic engineering is the process of manually adding new DNA to an organism. The goal is to add one or more new traits that are not already found in that organism. Examples of genetically engineered (transgenic) organisms currently on the market include plants with resistance to some insects, plants that can tolerate herbicides, and crops with modified oil content. New DNA may be inserted in the host genome by first isolating and copying the genetic material of interest using molecular cloning methods to generate a DNA sequence, or by synthesizing the DNA, and then inserting this construct into the host organism. 

Therefore, the correct answer is option D.

The first step in genetic engineering as

  1. Isolation of protein

  2. Purification of protein

  3. Isolation of genetic material

  4. Isolation of RNA


Correct Option: C
Explanation:
The first step in genetic engineering involves choosing and isolating the gene that will be inserted into/removed from the genetically modified organism. Then the gene must be combined with a promoter and terminator region as well as a selectable marker gene. Then the gene must be spliced into the target's DNA. For animals, the gene must be inserted into embryonic stem cells. The resulting organism must have the presence of the target gene confirmed. 
Therefore, the correct answer is option C.

Advancement in genetic engineering has been possible due to the discovery of 

  1. Exonucleases

  2. Endonucleases

  3. Transposons

  4. Oncogenes


Correct Option: B
Explanation:

A restriction enzyme or restriction endonuclease is an enzyme that cuts DNA at or near specific recognition nucleotide sequences known as restriction sites. These enzymes are found in bacteria and archaea and provide a defense mechanism against invading viruses. Inside a prokaryote, the restriction enzymes selectively cut up foreign DNA in a process called restriction; while host DNA is protected by a modification enzyme (a methyltransferase) that modifies the prokaryotic DNA and blocks cleavage. Together, these two processes form the restriction modification system. These enzymes are routinely used for DNA modification in laboratories, and are a vital tool in molecular cloning.

Therefore, the correct answer is option B.

The process of 'in vitro' manipulation of DNA is called as

  1. Tissue culture

  2. Genetic engineering

  3. Cloning

  4. DNA fingerprinting


Correct Option: B
Explanation:
Recombinant DNA technology is also referred to as gene cloning or in- vitro genetic manipulation. Genetic manipulation or engineering alters the genetic make-up of an organism using techniques that remove heritable material or that introduce DNA prepared outside the organism either directly into the host or into a cell that is then fused or hybridized with the host. This involves using recombinant nucleic acid (DNA or RNA) techniques to form new combinations of heritable genetic material followed by the incorporation of that material either indirectly through a vector system or directly through micro-injection, macro-injection and micro-encapsulation techniques.
Therefore, the correct answer is option B.

Genetic engineering is possible, because

  1. The phenomenon of transduction in bacteria is well understood

  2. We can see DNA by electron microscope

  3. We can cut DNA at specific sites by endonucleases such as DNAase I

  4. Restriction endonucleases purified from bacteria can be used in vitro


Correct Option: D
Explanation:

A restriction enzyme or restriction endonuclease is an enzyme that cuts DNA at or near specific recognition nucleotide sequences known as restriction sites. These enzymes are found in bacteria and archaea and provide a defense mechanism against invading viruses. Inside a prokaryote, the restriction enzymes selectively cut up foreign DNA in a process called restriction; while host DNA is protected by a modification enzyme (a methyltransferase) that modifies the prokaryotic DNA and blocks cleavage. Together, these two processes form the restriction-modification system. These enzymes are routinely used for DNA modification in laboratories and are a vital tool in molecular cloning.

Therefore, the correct answer is option D.

In genetic engineering, the term vector is applied for 

  1. Plasmids

  2. Active viruses

  3. Source of DNA

  4. Cell which receives DNA


Correct Option: A
Explanation:

In molecular cloning, a vector is a DNA molecule used as a vehicle to artificially carry foreign genetic material into another cell, where it can be replicated and/or expressed. A vector containing foreign DNA is termed recombinant DNA. The four major types of vectors are plasmids, viral vectors, cosmids, and artificial chromosomes. Of these, the most commonly used vectors are plasmids. 

Therefore, the correct answer is option A.

The technology that is used to make desired change on gene structure is

  1. Genetic engineering

  2. Recombinant DNA technology

  3. Gene cloning

  4. All of the above


Correct Option: D
Explanation:

Genetic engineering, also called as genetic modification, is the direct manipulation of an organism's genome using biotechnology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species to produce improved or novel organisms. 

Cloning is the process of producing similar populations of genetically identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. The term clone is used in horticulture to refer to descendants of a single plant which were produced by vegetative reproduction. 
Recombinant DNA technology is a series of procedures that are used to join together (recombine) DNA segments. A recombinant DNA molecule is constructed from segments of two or more different DNA molecules. 

The first step in genetic engineering is

  1. Isolation of protein

  2. Purification of protein

  3. Isolation of genetic material

  4. Isolation of RNA


Correct Option: C
Explanation:

Genetic engineering, also called as genetic modification, is the direct manipulation of an organism's genome using biotechnology. It is a set of technologies used to change the genetic makeup of cells, including the transfer of genes within and across species to produce improved or novel organisms. New DNA may be inserted in the host genome by first isolating and copying the genetic material of interest using molecular cloning methods to generate a DNA sequence, or by synthesizing the DNA, and then inserting this construct into the host organism. 

Genetic engineering is used in

  1. Gene therapy

  2. Vaccine production

  3. Obtaining transgenic plants

  4. All of the above


Correct Option: D
Explanation:
Genetic engineering has applications in medicine, research, industry and agriculture and can be used on a wide range of plants, animals and microorganisms. In medicine, genetic engineering has been used to mass-produce insulin, human growth hormones, human albumin, monoclonal antibodies, anti haemophilic factors, vaccines, and many other drugs. In research, organisms are genetically engineered to discover the functions of certain genes. Industrial applications include transforming microorganisms such as bacteria or yeast or insect mammalian cells with a gene coding for a useful protein. Mass quantities of the protein can be produced by growing the transformed organism in bioreactors using fermentation, then purifying the protein. Genetic engineering is also used in agriculture to create genetically-modified crops or genetically-modified organisms
So, the correct answer is 'All of the above'

Restriction enzymes are isolated chiefly from

  1. Algae

  2. Fungi

  3. Protozoa

  4. Prokaryotes 


Correct Option: D
Explanation:
Restriction endonucleases are enzymes, isolated chiefly from prokaryotes, that recognize specific nucleotide sequences within double stranded DNA and cleaves it at these sites. These restriction endonucleases facilitate the specific fragmentation of double stranded DNA and are very useful for DNA sequence analysis. These enzymes can be classified into three groups. Type I and type III enzymes carry a modification (methylation) and an ATP requiring restriction (cleavage) activity within the same protein. Both types of enzymes identify unmethylated sequences in substrate DNA, but type I enzymes cleave randomly, whereas type III enzymes cut DNA at specific sites. Type II restriction enzyme consist of a separate restriction endonuclease and a modification methylase. 

Various enzymes and hormones can be produced on a large scale by employing the recombinant __________ technique.

  1. DNA

  2. RNA

  3. Viral

  4. Bacterial


Correct Option: A
Explanation:

Recombinant DNA (or rDNA) is made by combining DNA from two or more sources. In practice, the process often involves combining the DNA of different organisms. The process depends on the ability to cut and re-join DNA molecules at points which are identified by specific sequences of nucleotide bases called restriction sites. DNA fragments are cut out of their normal position in the chromosome using restriction enzymes (also called restriction endonucleases) and then inserted into other chromosomes or DNA molecules using enzymes called ligases.

Therefore, the correct answer is option A.

The recent techniques used for separating fragments of DNA is

  1. Northern blotting

  2. Southern blotting

  3. Eastern blotting

  4. Western blotting


Correct Option: B
Explanation:
Southern blotting is a common technique used in molecular biology to separate and characterize DNA. Southern blotting is a technique used to determine the presence of a specific DNA sequence within a mixture via agarose gel electrophoresis. The Northern blot is a technique used in molecular biology research to study gene expression by detection of RNA (or isolated mRNA) in a sample. The Eastern blot is a biochemical technique used to analyze protein post translational modifications such as lipids, phospho-moieties and glycoconjugates. Western blotting is an adaptation of the Southern blot procedure, used to identify specific amino-acid sequences in proteins.

DNA sequence comparison is a powerful tool in studying evolution. However, there are limitations to what it can tell us about the history of life on Earth.
What is a limitation of this technology?

  1. It is only possible to obtain DNA samples from extant or recently extinct species.

  2. It is possible that an organism will have genes for non-functional proteins.

  3. Mutations can occur randomly in genomes.

  4. There is greater variation in DNA sequences that in amino acid sequences.


Correct Option: C
Explanation:
DNA sequence comparison tools like BLAST, CLUSTAL W etc are some of the powerful tools used in understanding the similarity, relatedness and other phylogenetic studies between two or more sequences at the same time. Mutations act as the limitation of DNA sequence comparison technology as they can occur randomly throughout the genome with time and hence could distort the sequence comparison results and hamper the assessment for statistical significance.
so, the correct answer is 'Mutations can occur randomly in genomes'

Which one of the following is related with genetic engineering?

  1. Plasmids

  2. Mitochondria

  3. Mutations

  4. Ribosomes


Correct Option: A
Explanation:

In molecular cloning, a vector is a DNA molecule used as a vehicle or carrier which carries the desired gene from donor to recipient cell, where it can be replicated and/or expressed. The plasmid is extrachromosomal circular DNA which acts as vector DNA. The plasmid is the most important vector as it possesses multiple cloning sites, an origin of replication and a selectable marker.

Using recombinant DNA technology, genes from a donor cell can be inserted into a bacterium for DNA replication and protein synthesis. The kind of cells that can be used as gene donors in this technology are

  1. Bacteria only

  2. Either yeast or bacteria

  3. Eukaryotic cells only

  4. Any of these


Correct Option: D
Explanation:

The production of a recombined bacterium using a gene from a foreign donor and the synthesis of a protein encoded by the recombinant DNA molecule. The genes used as a donor in recombinant DNA technology are commonly obtained from bacteria, yeast or any eukaryotic host organism. 

So, the correct option is 'Option D' .

In genetic engineering, a DNA segment (gene) of interest is transferred to the host cell through a vector. Consider the following four agents in this regard and select the correct option about which one or more of these can be used as a vector/vectors?
(i) Bacterium
(ii) Plasmid
(iii) Plasmodium
(iv) Enzyme

  1. (ii) only

  2. (i) and (ii) only

  3. (i), (iii) and (iv)

  4. (iv) only


Correct Option: A
Explanation:

In molecular cloning, a vector is a DNA molecule used as a transport to artificially carry foreign genetic material into another cell, where it can be replicated and expressed. A vector containing foreign DNA is termed recombinant DNA. The four major types of vectors are plasmids, viral vectors, cosmids, and artificial chromosomes. Of these, the most commonly used vectors are plasmids.

Therefore, the correct answer is option A.

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