MicroBiology MCQs with Answer and Explnation | Chapter 36

Answer: Molecular scissors

Restriction endonucleases are enzymes that recognize specific DNA sequences and cleave the DNA at or near these sequences. They are commonly referred to as “molecular scissors” because of their ability to precisely cut DNA at specific sites, resembling the action of scissors cutting a molecular thread.

The other options are incorrect:

• Molecular stichers: Restriction endonucleases do not stitch or join DNA; their primary function is to cleave or cut DNA.
• DNA synthesis: DNA synthesis involves the creation of new DNA strands, often catalyzed by enzymes called polymerases. Restriction endonucleases do not participate in DNA synthesis.
• Polymerases: Polymerases are enzymes involved in DNA synthesis, not the cleavage of DNA. Restriction endonucleases are distinct enzymes with a different function.

Answer: The first letter of the genus in which it is present

In the restriction endonuclease EcoRI, the “E” stands for the first letter of the genus (Escherichia) in which it is naturally present. EcoRI is derived from Escherichia coli, the bacterium from which this particular restriction endonuclease was originally isolated.

The other options are incorrect:

• Extraction: “E” in EcoRI does not stand for extraction. It refers to the genus name of the bacterium.
• Endonuclease: While EcoRI is an endonuclease, the “E” specifically denotes the genus from which it was isolated.
• Endangered: “E” in EcoRI does not stand for endangered. It refers to the genus name of the bacterium.

Answer: Variable number tandem repeats

VNTR stands for Variable Number Tandem Repeats. These are sections of DNA where short sequences of nucleotides are repeated one after another, and the number of repeats can vary between individuals. The other options have incorrect components:

The other options are incorrect:

• Variable nucleotide triplet repeat: While “triplet” refers to three nucleotides, VNTRs can have repeats of longer sequences.
• Variable nucleoside tandem repeat: “Nucleoside” refers to individual sugars and bases, while VNTRs focus on repeating sequences of nucleotides (bases linked to a sugar).
• Variable nucleoside triplet repeat: Combines incorrect elements of the previous options.

Answer: Palindromes with rotational symmetry

Restriction endonucleases recognize and cut specific short sequences on DNA called palindromes with rotational symmetry. These sequences read the same forward and backward (like “madam”) and exhibit symmetry when rotated 180 degrees (like a four-leaf clover). This unique characteristic allows the enzyme to bind efficiently and precisely to the DNA regardless of its orientation.

The other options are incorrect:

• Non-coding sequences: While restriction sites can be found in non-coding regions, they are not specific to them and can also occur in coding regions.
• Satellites: These are repetitive DNA sequences, but not all satellites are recognized by restriction enzymes, and only some with specific palindromic patterns might be.
• Tandem repeats: Tandem repeats can be present within restriction sites, but not all restriction sites are solely composed of tandem repeats, and palindromic symmetry is crucial for recognition.

Answer: Vector, desired gene, mRNA of desired gene, host, restriction enzymes, ligases

The main tools required for recombinant DNA technology include:

Vector: A carrier molecule (commonly a plasmid or viral vector) used to transfer the desired gene into the host organism.

Desired gene: The specific gene of interest that is to be inserted or expressed in the host.

Host: The organism or cell line that will harbor and express the recombinant DNA.

Restriction enzymes: Enzymes used to cut DNA at specific recognition sites, allowing the insertion of the desired gene into the vector.

Ligases: Enzymes that facilitate the joining or ligation of DNA fragments by catalyzing the formation of phosphodiester bonds.

The other options are incorrect:

• Vector, desired gene: Additional tools such as a host organism and enzymes for DNA manipulation are needed in recombinant DNA technology.
• Desired gene, host, vector: Enzymes for DNA manipulation, like restriction enzymes and ligases, are crucial tools in recombinant DNA technology.
• Vector, desired gene, mRNA of desired gene, host: This option includes mRNA but is not typically required as a tool for recombinant DNA technology. The essential components are vector, desired gene, host, restriction enzymes, and ligases.

Answer: In some humans it induced antibody production

While cow and pig insulin were effective in lowering blood sugar, one major problem was that in some humans, it induced antibody production. This means the immune system mistakenly recognized the animal insulin as foreign and attacked it, potentially reducing its effectiveness or causing allergic reactions.

The other options are incorrect:

• The insulin was not active: Generally, animal insulin was active in humans, though its exact timing and effectiveness could vary compared to human insulin.
• It reduces the weight of patients: Insulin’s primary function is to regulate blood sugar, not directly influence weight.
• Loss of memory power: There’s no evidence linking animal insulin specifically to memory loss. While uncontrolled diabetes can have various complications, they wouldn’t directly relate to the type of insulin used.

Answer: E. coli and also Ligase encoded by T4 phage

DNA Ligase used in recombinant DNA technology is obtained from both E. coli and the Ligase encoded by the T4 phage. DNA Ligase is an enzyme that catalyzes the formation of phosphodiester bonds between adjacent DNA fragments, sealing nicks and joining DNA strands during the process of recombinant DNA technology.

The other options are incorrect:

• E. coli only: While E. coli is a common source of DNA Ligase, it is not the exclusive source. Ligase encoded by the T4 phage is also used.
• Saccharomyces: Saccharomyces (yeast) is not a typical source of DNA Ligase in recombinant DNA technology.
• Retroviruses: Retroviruses are not a source of DNA Ligase. DNA Ligase is typically obtained from bacterial sources like E. coli and phage sources like T4 phage.

Answer: Genetic finger printing

Genetic fingerprinting analyzes unique variations in an individual’s DNA, allowing identification in forensic investigations. It doesn’t involve culturing cells, fusing them, or modifying genes.

The other options are incorrect:

• In vitro culture: This technique grows isolated cells or tissues in a controlled environment for research or medical applications. It isn’t typically used for forensic identification.
• Hybridoma technology: This technique fuses B cells with myeloma cells to produce hybridomas that create specific antibodies. It’s used in developing diagnostic and therapeutic drugs, not in forensic science.
• Gene therapy: This technique introduces genetic material into cells to treat genetic diseases. It’s a medical treatment, not an identification tool.

Answer: All of these

Genetic fingerprinting analyzes unique variations in DNA, allowing for highly accurate identification in various situations. Its applications extend beyond just criminal cases and encompass parentage testing and immigration control.

The other options are incorrect:

• Identifying criminals involved in rape, murder etc.: DNA evidence from crime scenes can be matched to individual suspects, strengthening investigations and aiding in prosecutions.
• Establishing the parentage of a disputed child: By comparing the DNA of the child with potential parents, genetic fingerprinting can definitively determine biological relationships.
• Identifying illegal immigrants: In some countries, DNA testing may be used as part of immigration procedures to verify identities and detect fraudulent documentation.

Answer: Restriction fragment length polymorphism

RFLP is a technique in molecular biology that takes advantage of variations in DNA sequences to distinguish between individuals or study genetic relationships. It involves cutting DNA with specific enzymes and analyzing the resulting fragments.

The other options are incorrect:

• Repeated fragment length polymorphism: This term doesn’t accurately describe the technique, as it’s not about repeated fragments but rather variations in fragment lengths due to restriction enzyme cutting sites.
• Renewed fragment length polymorphism: This term is also inaccurate, as the fragments aren’t renewed but rather produced by the initial cutting of DNA.
• Required fragment length polymorphism: This term doesn’t capture the essence of the technique, which doesn’t focus on specific required fragment lengths but rather analyzes the naturally occurring variations in fragment lengths.

Answer: Curing genetic disorders

Gene therapy aims to treat or prevent genetic diseases by introducing functional copies of genes or modifying existing ones. It directly addresses the root cause of genetic disorders, aiming for potential cures.

The other options are incorrect:

• Saving endangered species: While the concept of using gene therapy to conserve endangered species has been explored, it’s still in its early stages and faces substantial technical and ethical challenges. Currently, gene therapy is primarily focused on human healthcare.
• Clonal propagation: This technique utilizes existing plant tissues to produce genetically identical copies. It doesn’t involve modifying genes but rather replicates them as they are.
• Producing monoclonal antibodies: Hybridoma technology, utilizing fused B cells, is the primary method for producing monoclonal antibodies. Gene therapy, on the other hand, alters genetic material within cells, not creating specific antibodies.

Answer: Probe

A probe is a small, 15-30 bases long nucleotide sequence used in molecular biology to detect the presence of complementary sequences in a DNA sample. In the context of DNA fingerprinting, probes are often labeled with a detectable marker and used to identify specific DNA sequences.

The other options are incorrect:

• RFLP (Restriction Fragment Length Polymorphism): This is a technique used in DNA fingerprinting, but it refers to the analysis of variations in DNA fragment sizes generated by cutting the DNA with specific enzymes. It doesn’t directly involve probes.
• VNTR (Variable Number Tandem Repeat): VNTRs are specific types of DNA sequences that can vary in the number of times a short sequence is repeated. While probes can be designed to target VNTRs, they are not synonymous with probes themselves.
• Reporter gene: This is a gene that encodes a protein that can be easily detected, often used in genetically modified organisms or research experiments. It’s not directly involved in the detection of specific DNA sequences like probes are.

Answer: 32 P

A radioactive probe used in DNA fingerprinting often contains 32 P (phosphorus-32). Radioactive labeling with 32 P allows for the detection and visualization of the probe on X-ray film or other imaging systems.

The other options are incorrect:

• 14C: Carbon-14 is another radioactive isotope, but it emits beta particles with lower energy, making it less sensitive for use in DNA fingerprinting. It also has a much longer half-life (5,730 years), posing long-term storage concerns.
• 12N: Nitrogen-12 is not radioactive and therefore wouldn’t be used as a label for a radioactive probe.
• pUC18: This is a type of cloning vector commonly used in molecular biology experiments. It’s not a radioactive isotope and doesn’t function as a DNA label.

Answer: DNA segments

Electrophoresis, a crucial technique in DNA fingerprinting, separates DNA segments based on their size and charge. It allows scientists to visualize the unique pattern of DNA fragments in an individual’s sample, forming the basis for identification.

The other options are incorrect:

• Cells from DNA: Electrophoresis cannot directly separate cells from DNA. It works on molecules, not whole cellular structures.
• Tissues: Similar to cells, tissues are large and complex structures beyond the resolving power of electrophoresis, which focuses on individual molecules.
• RNA from DNA: While electrophoresis can be used to separate both DNA and RNA, in DNA fingerprinting, the primary focus is on analyzing DNA fragments.

Answer: Polymerase chain reaction

In DNA fingerprinting, PCR amplifies even tiny amounts of DNA from crime scene samples into millions of copies, making it detectable and usable for analysis. This crucial step allows accurate identification even with limited evidence.

The other options are incorrect:

• Autoradiography: This technique visualizes radioactive labels, but it doesn’t amplify DNA itself. While used in earlier DNA fingerprinting methods, it’s not directly responsible for DNA multiplication.
• Southern blotting: This technique transfers DNA fragments onto a membrane for hybridization with probes, again not involved in amplifying DNA copies. It analyzes existing DNA, not creating more.
• Electrophoresis: This technique, while essential for separating DNA fragments in fingerprinting, doesn’t amplify DNA. It helps visualize existing fragments after they’ve been multiplied.

Answer: It was discovered by a scientist, E.M. Southern.

The name “Southern blotting” actually pays homage to the scientist who invented the technique, Edwin M. Southern, not to any geographical location or direction. He published his pioneering work on this method in 1975, revolutionizing the field of molecular biology.

The other options are incorrect:

• The blotting is done from the south side: This is not true. The direction of blotting in the Southern blotting technique is not relevant to its name.
• It was popular in South-America: There’s no evidence to suggest that Southern blotting was particularly popular in South America compared to other regions.
• It was popular in southern countries: Similar to the previous option, there’s no specific connection between the technique’s name and its popularity in any particular geographical area.

Answer: Nitrocellulose membrane

In DNA fingerprinting, after electrophoresis, the DNA fragments in the gel are transferred to a nitrocellulose membrane for hybridization with labeled probes. This transfer allows the specific DNA fragments to bind to the membrane, facilitating the detection of particular sequences during hybridization.

The other options are incorrect:

• Agarose: This is the material used to make the gel for electrophoresis, not the final destination for the DNA fragments.
• Autoradiogram: This is a film used to visualize radioactive labels attached to probes after hybridization. It shows the location of bound probes on the membrane but is not the membrane itself.
• PCR: This is a technique used to amplify DNA before electrophoresis, not a subsequent step for transferred fragments.

Answer: Autoradiography

During DNA fingerprinting, when DNA nucleotides hybridize with a labeled probe, the detection is often done through autoradiography. Autoradiography involves exposing X-ray film to the labeled DNA, allowing visualization of the hybridized bands on the film through the emission of radioactive signals.

The other options are incorrect:

• Electrophoresis: Electrophoresis is a technique used to separate DNA fragments based on size but does not directly detect hybridization. It is often used in combination with other methods for DNA analysis.
• Polymerase chain reaction (PCR): PCR is a technique for amplifying DNA but does not directly detect hybridization. It is used to create sufficient copies of DNA before analysis.
• Hybridoma: Hybridoma technology is related to the production of monoclonal antibodies and is not directly involved in the detection of hybridization in DNA fingerprinting.

Answer: Any body cells

Somatic cell gene therapy specifically targets non-reproductive cells, excluding sperm and egg cells, to introduce functional genes and treat genetic diseases in the individual. This avoids passing the modified genes to future generations, a crucial ethical consideration.

The other options are incorrect:

• Sperm: Sperm cells are reproductive cells, and introducing genes into them would affect the germline, potentially leading to heritable changes. Somatic cell gene therapy focuses on non-reproductive cells.
• Egg: Eggs (oocytes) are reproductive cells, and introducing genes into them would affect the germline. Somatic cell gene therapy is designed to target non-reproductive cells.
• Germinal cells: Germinal cells include both sperm and egg cells. Introducing genes into germinal cells would impact the germline, leading to heritable changes. Somatic cell gene therapy, however, targets non-reproductive cells.

Answer: DNA finger printing

DNA fingerprinting is the most likely technique used in the scenario you described. It allows for highly accurate identification by analyzing the unique patterns of DNA variations in an individual. This makes it ideal for family reunification after disasters or adoptions where traditional identification methods might be unreliable.

The other options are incorrect:

• Gene therapy: This technique aims to treat genetic diseases by introducing functional genes into cells. It wouldn’t be used for family identification.
• Tissue culture: This technique involves growing isolated cells or tissues in a controlled environment, typically for research purposes. It’s not directly related to individual identification.
• Hybridoma technology: This technique produces hybrid cells that create specific antibodies. It’s primarily used in research and diagnostic applications, not family identification.

Answer: Molecular farming

The approach of transferring genes into animals to achieve large-scale production of proteins, often in milk or blood, is generally referred to as Molecular Farming. This technique involves using genetically modified animals or plants as bioreactors to produce pharmaceutical or industrial proteins.

The other options are incorrect:

• In vitro culture: In vitro culture generally refers to the cultivation of cells or tissues outside the organism in a controlled environment. Molecular farming involves whole organisms, not just cell cultures.
• Gene therapy: Gene therapy involves introducing, deleting, or replacing genes within an individual to treat or prevent disease. It is not focused on large-scale protein production.
• Hybridoma technology: Hybridoma technology is used to produce monoclonal antibodies, not for large-scale production of proteins in animals. Molecular farming is a more applicable term for this purpose.

Answer: DNA finger printing

RFLP (Restriction Fragment Length Polymorphism), VNTR (Variable Number Tandem Repeat), and Probe are all key terms associated with DNA fingerprinting. These techniques and tools play crucial roles in analyzing and identifying individuals based on their unique DNA patterns.

The other options are incorrect:

• Hybridoma technology: This technique uses fused B cells to produce monoclonal antibodies specific to a target antigen. It’s not directly involved in DNA analysis or fingerprinting.
• Tissue culture: This technique involves growing isolated cells or tissues in a controlled environment. While it can be used for genetic studies, it’s not specifically related to DNA fingerprinting techniques like RFLP, VNTR, or probe hybridization.
• CFT (Cell-free transfer): This term can refer to various processes, including the transfer of genetic material between cells or the movement of proteins through cell membranes. It’s not a specific technique associated with DNA fingerprinting.

Answer: SCID

In 1990, the first gene therapy was conducted on a 4-year-old girl with Severe Combined Immunodeficiency (SCID). SCID is a genetic disorder characterized by a severely compromised immune system, making individuals susceptible to severe infections.

The other options are incorrect:

• AIDS: AIDS (Acquired Immunodeficiency Syndrome) is caused by the HIV virus and primarily affects the immune system. The first gene therapy in 1990 was not conducted for AIDS but for SCID.
• CANCER: While gene therapy has been explored as a treatment for various cancers, the first gene therapy in 1990 was not conducted for cancer but for SCID.
• Malaria: Malaria is a parasitic infection transmitted by mosquitoes. The first gene therapy in 1990 was not conducted to treat malaria but for SCID, a genetic disorder affecting the immune system.

Answer: ADA enzyme

SCID (Severe Combined Immunodeficiency) is a genetic disorder characterized by the lack of functional T lymphocytes, B lymphocytes, and natural killer cells, leading to severe vulnerability to infections. This deficiency stems from a mutation in the gene encoding the adenosine deaminase (ADA) enzyme, which plays a crucial role in purine metabolism within immune cells.

The other options are incorrect:

• Insulin: Deficiency of insulin leads to diabetes mellitus, not SCID.
• Glucagon: Lack of glucagon affects glucose metabolism but not immune function.
• Dystrophin: Mutation in the dystrophin gene causes Duchenne muscular dystrophy, which affects muscle function, not immune response.

Answer: Bioreactor

A bioreactor is a device in which a substrate of low value is utilized by living cells or enzymes to generate a product of higher value. This process often involves the cultivation of microorganisms or cells under controlled conditions for the production of valuable substances, such as pharmaceuticals or biofuels.

The other options are incorrect:

• Test tube culture: Test tube culture typically refers to the cultivation of cells or microorganisms in small test tubes and is not specifically associated with the controlled production of valuable products from low-value substrates.
• Electrophoresis: Electrophoresis is a technique used for separating molecules based on their size and charge and is not related to the utilization of low-value substrates by living cells or enzymes.
• Chromatography: Chromatography is a technique used for separating and analyzing mixtures of substances but is not directly associated with the cultivation of cells or enzymes to generate products from low-value substrates.

Answer: Introducing the correct copy of the gene

Gene therapy aims to treat or cure genetic diseases by addressing the root cause of the problem – the faulty gene. This is primarily achieved by introducing a functional copy of the gene into the patient’s cells. This functional copy then takes over the role of the faulty gene, producing the necessary protein or enzyme that was previously deficient.

The other options are incorrect:

• Repairing the faulty gene: While directly repairing the mutated gene is also a potential approach in gene therapy, it’s still largely under development and not as widely used as introducing a functional copy.
• Adding new cells to the body: This strategy, known as cell therapy, can be used in conjunction with gene therapy, but it doesn’t directly involve modifying the patient’s own genes.
• Polymerase chain reaction (PCR): PCR is a technique used to amplify DNA fragments, but it’s not a therapeutic technique in itself. It might be used for diagnosis or for preparing genes for gene therapy treatments.

Answer: Both “Micro injection” and “Some viruses”

Gene therapy relies on delivering functional copies of genes into target cells to treat genetic diseases. This delivery can be achieved through several methods, but both microinjection and some specific viruses are currently among the most common and effective approaches.

The other options are incorrect:

• Microinjection: Microinjection is indeed one of the methods for introducing genes into cells during gene therapy. However, it is not the only method.
• Some viruses: The use of certain viruses (viral vectors) is another common method for delivering genes into cells during gene therapy. It involves modifying the viruses to carry therapeutic genes.
• Erythrocytes: Erythrocytes are red blood cells and are not commonly used as carriers for gene therapy. The primary methods involve microinjection or the use of certain viruses as vectors for gene delivery.

Answer: All of these

DNA fingerprinting, a powerful analytical technique, has diverse applications beyond just one specific area. While each option holds merit, “all of these” is the most accurate choice because DNA fingerprinting can be used effectively in:

• Identifying illegal immigrants: In some cases, immigration authorities may utilize DNA fingerprinting to verify family relationships or confirm the origin of individuals claiming specific citizenship. However, ethical considerations and legal frameworks surrounding privacy and data protection in such scenarios are crucial.
• Detecting the real parent of a child: DNA fingerprinting plays a significant role in resolving paternity and maternity disputes by providing highly accurate identification based on genetic signatures. This can bring legal clarity and emotional closure to families involved in such situations.
• Detecting the suspect involved in a crime: In forensic investigations, DNA fingerprinting serves as a powerful tool for matching biological evidence at crime scenes to individual suspects. This can provide compelling evidence in court proceedings and help bring perpetrators to justice.

Answer: Germline gene therapy

In germline gene therapy, functional genes are introduced into the sperm or egg cells. This type of gene therapy aims to modify the genetic material in the reproductive cells, potentially leading to the inheritance of the introduced genes by future generations.

The other options are incorrect:

• Somatic cell gene therapy: Somatic cell gene therapy involves introducing functional genes into non-reproductive cells of the body. The genetic modifications are not passed on to offspring in this type of therapy.
• Vegetative cell gene therapy: There is no widely recognized term “Vegetative cell gene therapy” in the context of gene therapy. The correct term for introducing genes into reproductive cells is germline gene therapy.
• Gametic gene therapy: While the term “Gametic” implies involvement with reproductive cells, the more commonly used and accepted term for introducing genes into reproductive cells is germline gene therapy.

Answer: Carbon source

Glucose is one of the most important components of tissue culture media and serves as the primary carbon source for the cultured cells. They rely on glucose for energy production and essential cellular processes like growth and metabolism.

The other options are incorrect:

• Growth regulator: While some specific chemicals in the media can influence cell growth, glucose itself doesn’t directly act as a growth regulator.
• Solidifying agent: Ingredients like agar or agarose are added to media to solidify it for specific culture techniques, not glucose.
• An antibiotic: Antibiotics are added to suppress the growth of unwanted bacteria and fungi, not to provide an energy source for the cultured cells.

Answer: Any cut part of the plant used in tissue culture

An explant in tissue culture refers to any cut part of a plant, such as a piece of leaf, stem, or root, that is used to initiate and establish a tissue culture. The explant contains cells that have the potential to regenerate and grow into a whole plant under suitable conditions.

The other options are incorrect:

• A plant extract used in tissue culture: While plant extracts might be added to the media for certain purposes, they wouldn’t be considered explants as they are not living plant tissues.
• A source of growth regulators added to media: Growth regulators are specific chemicals added to the media to influence cell growth or differentiation, not the explants themselves.
• Solidifying agent: Ingredients like agar or agarose are used to solidify the media, not plant tissue pieces.

Answer: Pairing b/w nucleotides of DNA sample with probe

In DNA fingerprinting, the term “hybridization” refers to the specific and complementary base pairing between the nucleotides of a single-stranded DNA probe and the target sequences on the DNA sample. This binding allows the probe to identify and highlight the desired regions within the larger DNA fragment, enabling subsequent detection and analysis.

The other options are incorrect:

• Pairing b/w the nucleotides of DNA and mRNA: This type of pairing occurs during transcription, not hybridization in DNA fingerprinting.
• Pairing b/w the nucleotides of probe with mRNA: Similar to the previous option, this interaction is not relevant to DNA fingerprinting, which focuses on DNA-DNA hybridization.
• Pairing between the nucleosides with mRNA: The term “nucleosides” refers to the individual sugar-phosphate backbone of a nucleotide, not the entire nucleotide (including the base). Pairing occurs between nucleotide bases, not just the sugar-phosphate backbones.

Answer: Sheep

Dolly, the first animal successfully cloned from an adult somatic cell, was a sheep. This groundbreaking scientific achievement in 1996 was significant for demonstrating the possibility of cloning mammals using nuclear transfer techniques.

The other options are incorrect:

• Camel: Camels have not yet been successfully cloned using adult somatic cell nuclear transfer.
• Rat: While rats have been cloned, Dolly was specifically the first mammal cloned from an adult somatic cell, which marked a significant leap forward in the field.
• Cow: Cows have been successfully cloned, but again, Dolly holds the specific distinction of being the first mammal cloned from an adult somatic cell.

Answer: Gene therapy

In a situation where a couple is concerned about the possibility of a genetic disorder in their unborn child, the doctor may suggest gene therapy as a potential solution. Gene therapy involves the introduction, correction, or replacement of genes to treat or prevent genetic disorders.

The other options are incorrect:

• Hybridoma technology: Hybridoma technology is primarily used for the production of monoclonal antibodies and is not directly involved in treating or preventing genetic disorders.
• ELISA: Enzyme-Linked Immunosorbent Assay (ELISA) is a technique used for detecting the presence of antibodies or antigens and is not a method for curing genetic disorders.
• DNA fingerprinting: DNA fingerprinting is used for identification purposes and is not a therapeutic technique for treating or preventing genetic disorders. It is more commonly used in forensic science and paternity testing.

Answer: Non-heritable

In somatic cell gene therapy, the genes introduced are non-heritable. This means that the genetic modifications made to the patient’s cells are not passed on to their offspring. The therapeutic genes are inserted into non-reproductive cells to treat a specific individual without affecting the germline.

The other options are incorrect:

• Heritable: As mentioned above, these genes cannot be passed on to offspring because they are not introduced into reproductive cells.
• Partially heritable: This concept doesn’t apply to somatic cell gene therapy as the introduced genes don’t even partially pass through to descendants.
• None of these: While the other options are incorrect, “non-heritable” accurately portrays the characteristic of genes introduced through somatic cell gene therapy.

Answer: Bioreactor

In biotechnology, bioreactors are the primary tools for mass culturing cells and microbes. These controlled environments provide optimal conditions for growth and production, often at much larger scales than achievable in simple test tubes.

The other options are incorrect:

• Test tube culture: While test tubes can be used for small-scale culture, they lack the features and capacity for scaling up production necessary for biotechnology applications.
• Autoclave: This equipment is used for sterilizing equipment and media, not for culturing cells or microbes.
• Electrophoresis: This technique is used for separating and analyzing different molecules, not for growth and production.

Answer: All of these

A bioreactor designed for effective mass culturing of cells and microbes needs all of the options you listed:

• Agitation for mixing of cells and medium: Proper mixing ensures efficient distribution of nutrients, oxygen, and waste products throughout the culture, preventing concentration gradients and improving overall growth.
• Sterile conditions: Contamination can quickly ruin large-scale cultures, so maintaining a sterile environment through proper sterilization procedures and design features is crucial.
• Regulation of temperature, aeration, etc.: Different cell types and processes have specific requirements for temperature, oxygen supply, pH, and other parameters. The ability to control and monitor these factors is essential for optimal growth and production

Answer: All of these

In vitro culture of plant parts, also known as plant tissue culture, requires a precise and controlled environment to ensure successful growth and development of the plant tissues. This encompasses several key factors:

• Controlled environmental condition: This includes maintaining factors like temperature, light intensity, humidity, and air circulation within optimal ranges for the specific plant species and culture technique.
• Aseptic condition: Sterile conditions are crucial to prevent contamination by bacteria, fungi, or other microorganisms, which can rapidly destroy the delicate plant tissues in culture.
• Maintenance of pH: The culture medium needs to have a proper pH level that falls within the desired range for optimal growth and metabolic activity of the plant cells.

Answer: Large scale production of desired substances by using cells / microbes

Bioreactors are used for the large-scale production of desired substances by using cells or microbes. They provide a controlled environment for the growth and cultivation of cells or microorganisms, allowing for the efficient production of various products, such as pharmaceuticals, enzymes, and biofuels.

The other options are incorrect:

• Kill bacteria: While there are methods for killing bacteria using specialized devices, bioreactors are not designed for this purpose. Their primary function is to promote controlled growth and production, not destruction.
• To store viruses: While some specialized containers hold viruses for research or medical purposes, bioreactors are not primarily used for viral storage. Their focus is on providing optimal conditions for cellular processes and product synthesis.
• To get chemicals: Chemicals can be obtained through various means, including extraction from natural sources or chemical synthesis. While bioreactors can produce certain chemicals through microbial activity, they are not solely used for generic chemical acquisition.

Answer: Solidifying agent

Agar is primarily added to tissue culture media as a solidifying agent. It provides a gel-like structure to the medium, allowing the plant tissues to grow upright and preventing them from clumping or sinking.

The other options are incorrect:

• Carbon source: Agar does not serve as a carbon source. It is a polysaccharide derived from seaweed and is added to tissue culture media primarily for solidification purposes.
• A growth regulator: Agar is not a growth regulator. It does not influence cell growth or development directly but is used to create a stable and supportive physical environment for the cultured cells.
• Nitrogen source: Agar is not a nitrogen source. Nitrogen is typically supplied in tissue culture media through compounds like nitrates or amino acids, while agar functions as a solidifying agent.

Answer: Multipotent

Stem cells found in umbilical cord blood are generally considered multipotent. Multipotent stem cells have the ability to differentiate into a limited range of cell types. While they are not as versatile as totipotent or pluripotent stem cells, they still possess the capacity to give rise to various cell types within a specific tissue or organ.

The other options are incorrect:

• Totipotent: These cells, like a fertilized egg, can give rise to all cell types in an organism. Umbilical cord blood stem cells don’t have this full potential.
• Pluripotent: These cells, like embryonic stem cells, can differentiate into all three germ layers (ectoderm, mesoderm, and endoderm) and generate all mature cell types. While umbilical cord blood stem cells have a wider range of differentiation potential than multipotent cells, they fall short of true pluripotency.
• Omnipotent: This term isn’t technically used in stem cell biology, as it represents an imaginary cell type with unlimited differentiation potential. No known cell type possesses this absolute capability.

Answer: Any cell that is totipotent can be cultured

Any cell that is totipotent can be cultured in plant tissue culture. Totipotent cells have the ability to give rise to all cell types and tissues in an organism, and they can be cultured to regenerate whole plants under appropriate conditions.

The other options are incorrect:

• The culturing of root is not possible: This statement is incorrect. Roots can be cultured in plant tissue culture, and various types of plant tissues, including roots, can be regenerated.
• The pH of the media need not be maintained: This statement is incorrect. Maintaining the pH of the culture media is crucial for the success of plant tissue culture, as it affects the availability of nutrients and the overall health of the cultured cells.
• Fruit juices are added to media as a carbon source: This statement is incorrect. While glucose or sucrose is commonly used as a carbon source in plant tissue culture media, adding fruit juices directly is not a standard practice.

Answer: Injecting a solution of DNA into nucleus of a cell

In biotechnology, microinjection is a method used for injecting a solution of DNA directly into the nucleus of a cell. This technique is commonly employed to introduce foreign genes or genetic material into a specific target cell, allowing for the manipulation of the cell’s genetic makeup.

The other options are incorrect:

• Injecting nutrients into a cell culture media: While adding nutrients to media is crucial for cell growth, it’s not done through microinjection. Nutrients are typically incorporated into the media itself.
• Injecting microbes into a cell culture media: Introducing microbes into cell culture media usually involves simpler methods like pipetting or mixing, not microinjection, which requires specialized equipment and techniques for precise delivery into individual cells.
• Injecting medicine to human beings: While medication administration can involve injections, microinjection in biotechnology specifically refers to the introduction of genetic material into cells, not the administration of drugs or other medical substances.

Answer: An alga

Agar used in plant tissue culture is extracted from an alga. Specifically, it is derived from certain species of red algae (seaweeds), such as Gelidium and Gracilaria. Agar provides a solidifying agent for the tissue culture medium, allowing for the growth and development of plant tissues in a controlled environment.

The other options are incorrect:

• A fungus: While some fungi produce polysaccharides with gelling properties, they are not typically used in agar production for plant tissue culture. Agar specifically comes from red algae.
• A bacterium: Bacteria also produce various polysaccharides, but none have the specific properties and composition of agar needed for plant tissue culture applications.
• A virus: Viruses are not cellular organisms and therefore cannot produce agar or any other complex biological compound.

Answer: The ability of a plant cell to develop into a complete plant

Totipotency refers to the ability of a plant cell to develop into a complete plant. Totipotent cells have the potential to differentiate into all cell types and tissues required for the formation of an entire organism, including roots, stems, leaves, and reproductive structures.

The other options are incorrect:

• The ability of a plant cell to arrest growth of a plant: This describes a specific function or response but isn’t directly related to the inherent potential of a cell.
• The ability of a plant cell to develop disease: This, again, focuses on a specific outcome (disease development) rather than the broader potential of the cell.
• The ability of a plant cell to develop into a callus: Callus formation is a step in the process of plant regeneration, but it doesn’t necessarily guarantee the development of a complete plant. Cells within a callus may not all be totipotent, and further differentiation needs to occur for plant regeneration.

Answer: To identify and sequence of all the genes present in the human body

The main aim of the Human Genome Project (HGP) was to identify and sequence all the genes present in the human body. The project aimed to map and understand the entire human genome, providing valuable information about the genetic instructions that govern human development and function.

The other options are incorrect:

• To introduce new genes to human beings: While gene therapy involves introducing new genes in specific cases, it was not the primary aim of the Human Genome Project. The HGP focused on mapping and understanding existing genes, not adding new ones.
• To remove disease-causing genes from humans: Gene editing and removal are complex technological challenges, and the HGP primarily focused on mapping and understanding genes, not manipulating them directly for therapeutic purposes.
• To improve techniques of fingerprinting: While the HGP laid the groundwork for understanding human genetic variation, its primary aim wasn’t directly related to improving fingerprinting techniques, which focus on specific regions of DNA used for identification purposes.

Answer: A transgenic cotton variety

Bt cotton is a transgenic cotton variety. It is genetically modified to express a toxin called Bacillus thuringiensis (Bt), which acts as an insecticide. This modification helps the cotton plant resist certain pests, particularly the cotton bollworm, reducing the need for external insecticide applications.

The other options are incorrect:

• A cotton variety obtained by crossing two different cotton plants: While traditional breeding methods like hybridization can improve cotton plants, Bt cotton specifically involves genetic modification techniques to introduce a foreign gene from a different organism (a bacterium).
• A cotton variety brought from South America: While cotton originated in South America, Bt cotton is not simply a specific variety imported from a particular region. It represents a GM technology applied to various cotton varieties worldwide.
• An insecticide sprayed on cotton plant: Bt cotton itself is not an insecticide, but rather a cotton plant genetically modified to produce its own toxin against specific insects. Unlike sprayed insecticides, this provides inherent protection within the plant’s tissues.

Answer: Embryo like structure settled from cells of callus

Somatic embryos are embryo-like structures that are derived from the cells of a callus in plant tissue culture. A callus is a mass of undifferentiated cells, and under specific conditions, these cells can be induced to differentiate and form structures resembling embryos without the process of fertilization.

The other options are incorrect:

• Embryos developed from zygote after fertilization: This describes the typical process of embryo development in sexually reproducing organisms, not somatic embryogenesis.
• Embryos developed from egg without fertilization: This process, known as parthenogenesis, involves development from an unfertilized egg cell, but it still occurs in reproductive tissues and doesn’t utilize callus formation.
• Embryo developed by ovules: Ovules are the structures in plants that contain the egg cell, but they themselves don’t develop into embryos. Embryo development happens within the ovule after fertilization.

Answer: Callus

An amorphous mass of loosely arranged thin-walled parenchyma cells developing from an explant is called a callus. In plant tissue culture, a callus is formed when cells dedifferentiate and divide, resulting in a mass of undifferentiated cells. Callus can be induced from various plant explants and is often used as a source for obtaining totipotent cells.

The other options are incorrect:

• Thallus: While thallus refers to the vegetative body of some lower plants like algae or fungi, it doesn’t specifically describe the structure formed from an explant in plant tissue culture.
• Callose: Callose is a polysaccharide deposited on cell walls in response to various stress or wounding conditions. It doesn’t necessarily represent a mass of dividing cells like a callus.
• Embryoids: Embryoids are embryo-like structures that can develop from callus cells during the process of somatic embryogenesis. However, they are not the initial amorphous mass of cells formed from the explant.

Answer: The seeds are golden yellow in color because of the presence of β–carotene

The name “Golden rice” is given to a rice variety because its seeds are golden yellow in color due to the presence of β–carotene. Golden rice has been genetically modified to produce higher levels of β–carotene, a precursor of vitamin A. This modification aims to address vitamin A deficiency in populations where rice is a staple food.

The other options are incorrect:

• It contains traces of gold: This is not the reason for the name. Golden rice gets its name from the golden yellow color of its seeds, which is a result of the increased β–carotene content.
• It is obtained from areas where gold mining is done: The name is not related to the geographical origin of the rice or its association with gold mining. It is named for its golden appearance due to β–carotene.
• It is made of gold: Golden rice is not made of gold; it is a genetically modified rice variety designed to address nutritional deficiencies by producing β–carotene, which gives it a golden color.