Samacheer Kalvi Class 12 Bio Zoology Solutions Chapter 9 Applications of Biotechnology

Question 1. The first clinical gene therapy was done for the treatment of ..........................
(a) AIDS
(b) Cancer
(c) Cystic fibrosis
(d) SCID
Answer: (d) SCID
In simple words: The first time doctors used gene therapy to treat a real patient, it was for a severe immune problem called SCID. This shows how early gene therapy focused on serious inherited conditions.

🎯 Exam Tip: Remember specific examples for key biotechnology milestones, as these are often tested for direct recall.

 

Question 2. Dolly, the sheep was obtained by a technique known as ..........................
(a) Cloning by gene transfer
(b) Cloning without the help of gametes
(c) Cloning by tissue culture of somatic cells
(d) Cloning by nuclear transfer
Answer: (d) Cloning by nuclear transfer
In simple words: Dolly was made by taking the nucleus from an adult cell and putting it into an egg cell that had its own nucleus removed. This method is called nuclear transfer, and it means the animal was cloned without needing sperm or egg cells in the usual way.

🎯 Exam Tip: Focus on the specific technique "nuclear transfer" when asked about Dolly's cloning, as it's the defining method.

 

Question 3. The genetic defect adenosine deaminase deficiency may be cured permanently by ..........................
(a) Enzyme replacement therapy
(b) periodic infusion of genetically engineered lymphocytes having ADA cDNA
(c) administering adenosine deaminase activators
(d) introducing bone marrow cells producing ADA into embryo at an early stage of development.
Answer: (d) introducing bone marrow cells producing ADA into embryo at an early stage of development.
In simple words: To fix ADA deficiency forever, the best way is to put healthy bone marrow cells into a baby when it is still a very early embryo. This ensures the correct ADA gene is present from the very beginning, leading to a permanent solution.

🎯 Exam Tip: Differentiate between temporary treatments (like enzyme therapy) and permanent cures for genetic disorders when answering such questions.

 

Question 4. How many amino acids are arranged in the two chains of Insulin?
(a) Chain A has 12 and Chain B has 13
(b) Chain A has 21 and Chain B has 30 amino acids
(c) Chain A has 20 and chain B has 30 amino acids
(d) Chain A has 12 and chain B has 20 amino acids
Answer: (b) Chain A has 21 and Chain B has 30 amino acids
In simple words: Insulin is made of two parts, or chains. Chain A has 21 tiny building blocks called amino acids, and Chain B has 30 of them. These chains are linked together to make the full insulin molecule.

🎯 Exam Tip: Remember the exact number of amino acids in each chain of insulin, as this is a common fact-based question.

 

Question 5. PCR proceeds in three distinct steps governed by temperature, they are in order of.........................
(a) Denaturation, Annealing, Synthesis
(b) Synthesis, Annealing, Denaturation
(c) Annealing, Synthesis, Denaturation
(d) Denaturation, Synthesis, Annealing
Answer: (a) Denaturation, Annealing, Synthesis
In simple words: PCR works in a specific order: first, DNA unwinds (denaturation); then, small starter pieces attach (annealing); and finally, new DNA copies are built (synthesis). This cycle makes many copies of a DNA segment.

🎯 Exam Tip: It is crucial to remember the exact sequence of PCR steps (Denaturation, Annealing, Synthesis) as they are always temperature-dependent and occur in this fixed order.

 

Question 6. Which one of the following statements is true regarding DNA polymerase used in PCR?
(a) It is used to ligate introduced DNA in recipient cells
(b) It serves as a selectable marker
(c) It is isolated from a Virus
(d) It remains active at a high temperature
Answer: (d) It remains active at a high temperature
In simple words: The special DNA polymerase used in PCR, called Taq polymerase, works even when it's very hot. This is important because PCR needs high heat to separate DNA strands, and this enzyme doesn't break down then.

🎯 Exam Tip: The heat stability of Taq polymerase is its most critical feature for PCR, so always highlight this characteristic.

 

Question 7. ELISA is mainly used for.........................
(a) Detection of mutations
(b) Detection of pathogens
(c) Selecting animals having desired traits
(d) Selecting plants having desired traits
Answer: (b) Detection of pathogens
In simple words: ELISA is a test that helps find very small amounts of disease-causing germs or the body's reaction to them. It works by finding specific antibodies or antigens in a sample.

🎯 Exam Tip: Understand that ELISA detects antigens or antibodies, making it highly effective for identifying infections or immune responses.

 

Question 8. Transgenic animals are those which have
(a) Foreign DNA in some of their cells
(b) Foreign DNA in all their cells
(c) Foreign RNA in some of their cells
(d) Foreign RNA in all their cells
Answer: (b) Foreign DNA in all their cells
In simple words: Transgenic animals are special because scientists have put DNA from another species into them. This new DNA is present in every single cell of the animal, meaning the change can be passed on to its offspring.

🎯 Exam Tip: For an animal to be truly transgenic, the foreign DNA must be incorporated into its germline, ensuring its presence in all cells and heredity.

 

Question 9. Recombinant Factor VIII is produced in the .......................... cells of the Chinese Hamster
(a) Liver cells
(b) blood cells
(c) ovarian cells
(d) brain cells
Answer: (c) ovarian cells
In simple words: A special protein called Factor VIII, used for treating a bleeding disorder, is made using Chinese Hamster Ovarian (CHO) cells in labs. These cells are widely used in biotechnology to produce complex human proteins due to their ability to correctly fold and modify proteins.

🎯 Exam Tip: Remember specific cell lines like Chinese Hamster Ovarian (CHO) cells are commonly used in industrial biotechnology for producing therapeutic proteins.

 

Question 10. Vaccines that use components of a pathogenic organism rather than the whole organism are called ..........................
(a) Subunit recombinant vaccines
(b) attenuated recombinant vaccines
(c) DNA vaccines
(d) conventional vaccines
Answer: (a) Subunit recombinant vaccines
In simple words: These vaccines use only small parts of a germ, like a specific protein, to teach the body how to fight it. This makes them very safe because they don't contain the whole germ, so they can't cause the disease itself.

🎯 Exam Tip: Subunit vaccines are praised for their safety profile as they avoid the risks associated with whole-pathogen vaccines, even attenuated ones.

 

Question 11. Mention the number of primers required in each cycle of PCR. Write the role of primers and DNA polymerase in PCR. Name the source organism of the DNA polymerase used in PCR.
Answer:

• For each cycle of PCR, two primers are needed.
• Primers are small pieces of single-stranded DNA or RNA. They act as starting points for building new DNA strands, guiding where the copying process begins.
• DNA polymerase is an enzyme that makes new DNA molecules. It does this by adding building blocks called deoxyribonucleotides, making sure they match the original DNA template.
• The DNA polymerase used in PCR is called Taq polymerase. It comes from a heat-loving bacterium named *Thermus aquaticus*. This enzyme is crucial for PCR because it can withstand the high temperatures needed during the process, making it highly efficient.

In simple words: PCR uses two primers per cycle to start new DNA copies, and a special enzyme called DNA polymerase builds these copies. This enzyme comes from a bacterium that lives in hot places, so it can handle the heat needed for PCR.

🎯 Exam Tip: Clearly state the number of primers, their 'starter' role, and the unique heat-resistant nature and source of Taq polymerase for a complete answer.

 

Question 12. How is the amplification of a gene sample of interest carried out using PCR?
Answer: Gene amplification using PCR happens in three main steps: denaturation, annealing (also called renaturation or primer annealing), and synthesis (or primer extension). First, the double-stranded DNA is heated to a very high temperature, around 95 °C. This heat causes the two DNA strands to separate, or "denature," into single strands, which then serve as templates. Next, the mixture is rapidly cooled, typically to 50-60 °C. This allows short pieces of DNA called primers to attach, or "anneal," to specific sequences on each single DNA strand. Finally, the temperature is raised again, usually to 72 °C, for DNA synthesis. At this stage, Taq DNA polymerase extends the primers by adding new DNA building blocks, creating new complementary strands. These three steps are repeated many times, usually 25-35 cycles, to create billions of copies of the desired DNA. This entire process is known as DNA amplification, making it possible to study even tiny amounts of DNA.In simple words: PCR makes many copies of a gene by heating DNA to split its strands, cooling it so small pieces can attach, and then building new strands. This cycle repeats many times to multiply the DNA.

🎯 Exam Tip: Explain each step of PCR (denaturation, annealing, synthesis) by mentioning the temperature changes and the role of DNA strands, primers, and DNA polymerase.

 

Question 13. What has genetically engineered Insulin?
Answer: Genetically engineered insulin is insulin that is made using recombinant DNA technology. This means that the gene for human insulin is inserted into bacteria or yeast, which then produce the insulin. It was one of the first important medicines created using this advanced technology. In 1986, this human insulin became available under the brand name Humulin. This marked a major breakthrough in treating diabetes.In simple words: Genetically engineered insulin is human insulin made by changing bacteria or yeast to produce it. It was the first medicine made this way and is called Humulin.

🎯 Exam Tip: When defining genetically engineered insulin, emphasize the use of recombinant DNA technology and its significance as a pioneering pharmaceutical product.

 

Question 14. Explain how "Rosie” is different from a normal cow.
Answer: Rosie was the first transgenic cow, meaning she had a gene from another species (humans) added to her DNA. This made her special because she produced milk enriched with human alpha-lactalbumin, a protein. Her milk contained 2.4 grams of this protein per liter, making it more nutritious and balanced for babies compared to regular cow's milk. Rosie demonstrated how genetic engineering could be used to improve the nutritional value of animal products.In simple words: Rosie was special because she was a transgenic cow, meaning she had human genes. Her milk had extra human protein, making it better for babies than regular cow's milk.

🎯 Exam Tip: Highlight both "transgenic" and the specific human protein (alpha-lactalbumin) in Rosie's milk when explaining her uniqueness.

 

Question 15. How was Insulin obtained before the advent of rDNA technology? What were the problems encountered?
Answer: Before recombinant DNA (rDNA) technology, insulin was obtained from the pancreases of animals like pigs and cows. This animal insulin was then purified and used to treat people with diabetes. Although effective, this method faced some problems. The animal insulin had slight differences in its structure compared to human insulin. These minor differences sometimes caused allergic reactions in some patients, leading to discomfort or other immune responses. Sourcing insulin from animals also had ethical concerns and supply limitations.In simple words: Before new technology, insulin came from pig or cow pancreases. This caused problems because animal insulin was slightly different from human insulin and could cause allergies in some people.

🎯 Exam Tip: When discussing pre-rDNA insulin, specify its animal origin and the key problem of allergic reactions due to structural differences.

 

Question 16. ELISA is a technique based on the principles of antigen-antibody reactions. Can this technique be used in the molecular diagnosis of a genetic disorder such as Phenylketonuria?
Answer: Yes, the ELISA test can indeed be used to diagnose phenylketonuria (PKU). PKU is a genetic disorder where a person cannot make enough of an enzyme called phenylalanine hydroxylase. The ELISA test works by detecting specific antigens or antibodies. If scientists create special antibodies that can find this missing enzyme, then ELISA can be used. In this case, an unaffected person would show a positive result if their body has the enzyme and the specific antibodies react. However, a person with PKU would show negative results because they lack the enzyme, so there would be no reaction. This shows ELISA's versatility in diagnosing not just infectious diseases but also specific enzyme deficiencies linked to genetic conditions.In simple words: Yes, ELISA can test for phenylketonuria. This is because PKU means a person is missing a certain enzyme. If we make special antibodies to find this enzyme, ELISA can show if it's there or not, helping to diagnose the disorder.

🎯 Exam Tip: Emphasize that ELISA relies on detecting specific antigens or antibodies; therefore, it can diagnose a genetic disorder if a unique protein or enzyme linked to that disorder can be targeted by specific antibodies.

 

Question 17. Gene therapy is an attempt to correct a Genetic defect by providing a normal gene into the individual. By this the function can be restored. An alternate method would be to provide gene product known as enzyme replacement therapy, which would also restore the function. Which in your opinion is a better option? Give reasons for your answer.
Answer: Both gene therapy and enzyme replacement therapy aim to fix genetic defects, but gene therapy is generally a better option. Gene therapy works by replacing a faulty gene with a healthy one. Once the correct gene is put in, it can make the missing protein or enzyme permanently, leading to a complete and lasting recovery for the patient. In contrast, enzyme replacement therapy only provides the missing enzyme or protein for a short time. Patients need to get regular infusions of the enzyme, which doesn't offer a permanent cure. Also, enzyme replacement therapy is often very expensive over a long period. Gene therapy offers a one-time or few-time treatment with lasting effects, making it more effective for long-term health.In simple words: Gene therapy is better than enzyme replacement therapy. Gene therapy fixes the faulty gene forever, giving a permanent cure. Enzyme therapy only gives the missing product for a short time and needs to be repeated often, which can be costly.

🎯 Exam Tip: When comparing therapies, always highlight gene therapy's potential for a permanent cure by correcting the root cause (the gene), versus enzyme replacement therapy's temporary solution.

 

Question 18. What are transgenic animals? Give examples.
Answer: Transgenic animals are living organisms that have had extra, foreign DNA introduced into their genome. This process, called transgenesis, aims to give the animals new traits or to study specific genes. The foreign DNA that is put into them is called a transgene. These animals are also known as genetically engineered or genetically modified organisms. Because the new DNA becomes a stable part of their genetic material, these traits can be passed down to their offspring. Examples of transgenic animals include mice, cows, and pigs, which are often used in research or for producing specific proteins.In simple words: Transgenic animals are those with new DNA from other species put into them. This changes their genes and can give them new traits. Mice and cows are common examples.

🎯 Exam Tip: Define transgenic animals by mentioning the introduction of "foreign/exogenous DNA" and state that these animals are used for research or specific product production.

 

Question 19. If a person thinks he is infected with HIV, due to unprotected sex, and goes for a blood test. Do you think a test such as ELISA will help? If so why? If not, why?
Answer: Yes, an ELISA test would be very helpful in this situation. ELISA (Enzyme-Linked ImmunoSorbent Assay) is a highly accurate and sensitive test. It can detect tiny amounts of antigens (parts of the virus) or antibodies (the body's response to the virus) in a blood sample, even down to a nanogram range. For HIV, ELISA can find the antibodies produced by the body against the virus. A positive result would mean the person has been infected with HIV. Therefore, it is a crucial first step for diagnosing HIV infection after potential exposure.In simple words: Yes, ELISA can help detect HIV. It is a very sensitive test that can find tiny amounts of HIV parts or the body's reaction to the virus in blood, even at very low levels.

🎯 Exam Tip: When explaining ELISA for HIV, focus on its high sensitivity and its ability to detect antibodies produced against the virus as key diagnostic features.

 

Question 20. Explain how ADA deficiency can be corrected?
Answer: ADA (Adenosine Deaminase) deficiency is a severe immune problem that can be corrected in several ways. The most direct approach for severe combined immunodeficiency (SCID) is to provide the patient with a working ADA enzyme, which helps break down harmful biological products. In some children, this deficiency can be treated with bone marrow transplantation. Here, unhealthy immune cells are replaced with healthy ones from a donor. Another treatment option is enzyme replacement therapy, where functional ADA is regularly injected into the patient. For a more permanent solution, gene therapy can be used. In this method, lymphocytes (a type of immune cell) are taken from the patient's blood and grown in a lab. A healthy human gene that makes ADA is then put into these lymphocytes using a retrovirus. The genetically modified lymphocytes are then put back into the patient. While these cells are not permanent, periodic infusions can manage the condition. A permanent cure is possible if the gene for ADA is introduced into bone marrow cells at a very early embryonic stage.In simple words: ADA deficiency can be fixed by giving the missing enzyme, a bone marrow transplant, or gene therapy. Gene therapy involves adding a healthy ADA gene to a patient's immune cells. For a lasting fix, the gene can be put into a very early embryo.

🎯 Exam Tip: List the different approaches for correcting ADA deficiency, differentiating between temporary solutions like enzyme replacement and more permanent ones like gene therapy at early embryonic stages.

 

Question 21. What are DNA vaccines?
Answer: DNA vaccines are a new kind of vaccine that emerged around 1990. They work by stimulating the body's immune system using a DNA molecule. A DNA vaccine is made by taking a gene that codes for a specific antigenic protein (a protein that triggers an immune response) from a disease-causing organism. This gene is then put into a small circular piece of DNA called a plasmid. This plasmid, carrying the gene, is then put into the cells of the target animal or human. Once inside the body's cells, the DNA instructs these cells to make the antigenic protein. These proteins are then displayed on the cell surfaces. This display causes the immune system to create antibodies against the protein, preparing the body to fight off the real disease if it encounters it later. These vaccines are considered safer because they only use a few genes, not the whole disease-causing organism, and are easier and cheaper to make.In simple words: DNA vaccines use a small piece of DNA from a germ to teach your body to fight it. The DNA makes your cells produce a part of the germ, which helps your immune system learn to protect you.

🎯 Exam Tip: When defining DNA vaccines, explain that they involve a gene for an antigenic protein inserted into a plasmid, which then directs host cells to produce the antigen, stimulating immunity.

 

Question 22. Differentiate between Somatic cell gene therapy and Germline gene therapy.
Answer:Somatic Cell Gene Therapy:

1. Therapeutic genes are transferred into the body's somatic cells (non-reproductive cells).
2. Genes are introduced into cells like bone marrow cells, blood cells, or skin cells.
3. The changes made will not be passed down to future generations, as they only affect the treated individual.

Germ Line Gene Therapy:

1. Therapeutic genes are transferred into germ cells, such as egg cells or sperm cells, or early embryos.
2. Genes are introduced into eggs and sperm.
3. The genetic changes made are heritable, meaning they will be passed on to all later generations of offspring.

The choice between these two therapies depends on the desired outcome regarding heritability and ethical considerations.In simple words: Somatic cell gene therapy changes genes only in body cells, so it's not passed on. Germline gene therapy changes genes in reproductive cells (sperm or egg), so the changes can be inherited by future children.

🎯 Exam Tip: The key difference lies in heritability: somatic cell gene therapy affects only the individual, while germline gene therapy impacts future generations, bringing significant ethical implications.

 

Question 23. What are stem cells? Explain its role in the field of medicine.
Answer: Stem cells are special cells found in most multicellular animals that have not yet become a specific type of cell (undifferentiated). They can divide many times and stay in this unspecialized state. Stem cell research holds great promise for revolutionizing medicine because these cells can repair or replace damaged organs and tissues. Stem cells have a unique ability called 'cellular potency' and can renew themselves. They can differentiate into many different cell types, including all those found in the three primary germ layers (ectoderm, endoderm, and mesoderm) that form an embryo. In medicine, stem cells are used to develop cell-based therapies, such as growing new skin for burn victims or replacing diseased blood cells. They also help researchers understand how diseases develop and test new drugs safely.In simple words: Stem cells are basic cells that haven't decided what they want to be yet. In medicine, they are used to fix damaged body parts or grow new ones. They also help doctors understand diseases and test new medicines.

🎯 Exam Tip: Define stem cells by their key properties: undifferentiated, self-renewal, and cellular potency (ability to differentiate), then cite examples of their therapeutic applications.

 

Question 24. One of the applications of biotechnology is 'gene therapy" to treat a person born with a hereditary disease
(i) What does "gene therapy" mean?
(ii) Name the hereditary disease for which the first clinical gene therapy was used.
(iii) Mention the steps involved in gene therapy to treat this disease.
Answer:
(i) Gene therapy is a process where defective genes are replaced with normal, healthy genes. This helps to make sure the body can produce the correct proteins or functions, leading to the proper traits (phenotype).
(ii) The first clinical gene therapy was used to treat a hereditary disease called SCID (Severe Combined Immuno Deficiency).
(iii) Gene therapy to treat SCID involves two main strategies: gene augmentation therapy and gene inhibition therapy. Gene augmentation therapy involves putting a working copy of a missing gene into the patient's cells to replace the missing gene product. Gene inhibition therapy, on the other hand, involves inserting an anti-sense gene. This anti-sense gene works by stopping the expression of a dominant gene that is causing the problem. These methods aim to restore normal immune function in affected individuals.In simple words: Gene therapy means replacing bad genes with good ones. The first disease treated was SCID. To treat it, doctors either add a missing gene or stop a bad gene from working, helping to fix the body's functions.

🎯 Exam Tip: When explaining gene therapy, clearly define it as gene replacement, name SCID as the first treated disease, and briefly describe the two main strategies (augmentation and inhibition).

 

Question 25. PCR is a useful tool for early diagnosis of Infectious disease. Elaborate.
Answer: PCR (Polymerase Chain Reaction) is a very useful tool for diagnosing infectious diseases early, as well as inherited disorders. It is highly specific and sensitive, meaning it can find even tiny amounts of specific DNA sequences. For infectious diseases, PCR can detect the pathogen's DNA in a clinical sample, such as blood, stool, spinal fluid, or sputum. This is much faster than traditional methods, which involve growing the organisms in a lab and performing many tests. PCR's ability to amplify even a single molecule of DNA helps in early detection, allowing for quicker treatment. For inherited diseases like sickle cell anemia, thalassemia, or phenylketonuria, PCR can detect the specific genetic mutations from samples like chorionic villi or amniocentesis. It also helps diagnose viral diseases, bacterial infections, and some cancers by detecting specific DNA or RNA sequences unique to the pathogen or abnormal cells.In simple words: PCR is great for finding diseases early because it can detect tiny bits of DNA from germs or faulty genes very quickly. This helps doctors start treatment sooner and find genetic problems before birth.

🎯 Exam Tip: Emphasize PCR's high specificity and sensitivity, its ability to detect pathogen DNA or genetic mutations, and its advantage over traditional methods in providing early diagnosis.

 

Question 26. What are recombinant vaccines? Explain the types.
Answer: Recombinant vaccines are a type of vaccine created using recombinant DNA technology. This technology allows scientists to develop vaccines that are safer and often more effective than traditional ones. Instead of using whole, weakened, or killed pathogens, these vaccines use only specific parts of the pathogen (like a protein) or genetically modified versions of them. There are several types of recombinant vaccines:

• **Subunit recombinant vaccines:** These vaccines use only a small component of the pathogen, such as a protein or a sugar, to trigger an immune response. They are very safe because they do not contain the whole organism.
• **Attenuated recombinant vaccines:** These vaccines use genetically modified versions of pathogenic organisms (bacteria or viruses). These modified organisms are made non-pathogenic, meaning they can't cause disease, but can still trigger a strong immune response.
• **DNA vaccines:** These vaccines involve injecting a small piece of DNA that codes for an antigen from the pathogen. The body's own cells then produce the antigen, prompting an immune response.

These various types of recombinant vaccines offer flexibility in design and improved safety.In simple words: Recombinant vaccines are made using genetic engineering, using only parts of germs or weakened germs to teach your body to fight. Types include subunit vaccines (just a part), attenuated vaccines (weakened germs), and DNA vaccines (using DNA to make a germ part).

🎯 Exam Tip: Define recombinant vaccines by their use of recombinant DNA technology and then clearly explain the distinct mechanisms and advantages of subunit, attenuated, and DNA vaccine types.

 

Question 27. Explain why cloning of Dolly, the sheep was such a major scientific breakthrough?
Answer: The cloning of Dolly the sheep was a huge scientific breakthrough because it proved that an entire animal could be created from a differentiated adult cell. Before Dolly, many scientists believed that once a cell had specialized (like a skin cell or a mammary gland cell), it could not go back to an unspecialized state to form a complete new organism. Dolly was created using a mammary gland cell from an adult sheep. Her birth showed that the DNA from an adult, specialized cell could be reprogrammed to direct the development of a full, healthy organism. This achievement opened up new possibilities in genetics, regenerative medicine, and the understanding of cell development, making it a landmark event in biological science.In simple words: Dolly the sheep was a big breakthrough because she showed that a whole animal could be grown from a single adult body cell. This proved that specialized cells could be reset to make a new life, which was a huge discovery for science.

🎯 Exam Tip: The key point of Dolly's breakthrough is demonstrating that a fully differentiated adult somatic cell's DNA can be reprogrammed to create a whole organism, challenging previous biological dogma.

 

Question 28. Mention the advantages and disadvantages of cloning.
Answer:Cloning has both advantages and disadvantages in science and medicine: **Advantages:**

• It helps in clinical trials and medical research by providing genetically identical animals for studying diseases and testing treatments.
• Cloning can aid in the production of important proteins and drugs in the field of medicine.
• It greatly helps in stem cell research, as cloned embryos can be a source of patient-specific stem cells.
• Animal cloning can be used to help save endangered species by creating new individuals from existing genetic material.

**Disadvantages:**

• Many animal and human rights groups see cloning as a threat to biodiversity and evolution, potentially impacting populations and ecosystems.
• The cloning process is very complicated, time-consuming, and expensive.
• Cloning can cause animals to suffer, with many cloned animals facing health problems.
• Studies show that cloned animals and their surrogate mothers often have bad health outcomes and higher death rates.
• Eating meat from cloned animals might raise concerns about human health.
• Cloned animals often age faster and are less healthy than naturally born animals, as seen with Dolly the sheep.
• Cloning can also lead to more genetic disorders in animals.
• A high percentage, over 90%, of cloning attempts fail to produce healthy offspring.

In simple words: Cloning helps medical research and saving rare animals. But it is very hard, costly, can cause suffering, and many attempts fail. It also raises concerns about animal health and human health risks.

🎯 Exam Tip: For advantages, focus on research, drug production, and conservation. For disadvantages, emphasize ethical concerns, low success rates, health issues in clones, and high costs.

 

Question 29. Explain how recombinant Insulin can be produced.
Answer: The production of insulin using recombinant DNA technology began in the late 1970s. This technique involves taking the human insulin gene and inserting it into small circular DNA molecules called plasmids, typically found in *E. coli* bacteria. The bacteria then act as tiny factories. Insulin is initially made as a precursor called pre-pro insulin. This molecule contains the A and B chains of insulin, along with a third chain (C-peptide) and a leader sequence. After the bacteria produce this long chain, the leader sequence is removed. Then, the C-peptide is cut out, leaving only the A and B polypeptide chains. These A and B chains are then linked together to form the complete, functional human insulin. This method allows for the safe and mass production of human insulin, which is essential for treating diabetes.In simple words: Recombinant insulin is made by putting the human insulin gene into bacteria like *E. coli*. These bacteria then produce a long insulin chain. This long chain is then cut to make the two main insulin parts, A and B, which are joined to form full human insulin.

🎯 Exam Tip: Describe the process starting with gene insertion into bacteria, emphasizing the initial production of a precursor molecule (pre-pro insulin) and its subsequent processing into mature A and B chains.

 

Question 30. Explain the steps involved in the production of recombinant hGH.
Answer: Recombinant human Growth Hormone (hGH) can be produced using recombinant DNA technology. The process begins by isolating the specific gene for human growth hormone from human pituitary gland cells. Once isolated, this gene is inserted into a plasmid, which acts as a vector. This plasmid, now carrying the hGH gene, is then transferred into *E. coli* bacteria. The *E. coli* bacteria, having received the new gene, begin to produce human growth hormone. After the bacteria have produced a sufficient amount of hGH, they are grown in a large culture. Finally, the recombinant *E. coli* are harvested from the culture, and the mass production of hGH is carried out using fermentation technology. This method allows for the production of hGH in large quantities, which is used to treat growth disorders.In simple words: To make recombinant hGH, the human gene for growth hormone is put into bacteria. These bacteria then grow and make lots of hGH. This hGH is then collected to be used as medicine.

🎯 Exam Tip: Outline the steps clearly: isolate the hGH gene, insert it into a plasmid, transfer to *E. coli*, allow *E. coli* to produce hGH, and then isolate and purify the hormone.

 

12th Bio Zoology Guide Applications of Biotechnology Additional Important Questions and Answers

 

12th Bio Zoology Guide Applications of Biotechnology One Mark Questions and Answers

 

Question 1. Statement 1: Human Insulin is a polypeptide Statement 2: It is composed of 52 amino acids
(a) Statement 1 is true. Statement 2 is false.
(b) Statement 1 is false. Statement 2 is true.
(c) Both statements 1 and 2 are true.
(d) Both statements 1 and 2 are false.
Answer: (a) Statement 1 is true. Statement 2 is false.
In simple words: Insulin is indeed a polypeptide (a chain of amino acids). However, it is made of 51 amino acids, not 52. So, the first statement is true, but the second one is false.

🎯 Exam Tip: Remember the exact composition of insulin: it is a polypeptide (protein) made up of 51 amino acids, not 52.

 

Question 2. Statement 1: Rosie was the first transgenic goat. Statement 2: Meat is enriched with human protein.
(a) Statement 1 is true. Statement 2 is false.
(b) Statement 1 is false. Statement 2 is true.
(c) Both statements 1 and 2 are true.
(d) Both statements 1 and 2 are false.
Answer: (d) Both statements 1 and 2 are false.
In simple words: Rosie was the first transgenic cow, not a goat, so the first statement is wrong. Also, Rosie produced milk with human protein, not meat, making the second statement also wrong.

🎯 Exam Tip: Carefully recall the species involved (Rosie was a cow) and the product enhanced (milk, not meat) for such true/false statement questions.

 

Question 3. Statement 1: Recombinant Hepatitis B vaccine is a live vaccine. Statement 2: It is obtained by cloning HB antigen gene in yeast.
(a) Statement 1 is true. Statement 2 is false.
(b) Statement 1 is false. Statement 2 is true.
(c) Both statements 1 and 2 are true.
(d) Both statements 1 and 2 are false.
Answer: (b) Statement 1 is false. Statement 2 is true.
In simple words: The first statement is incorrect because recombinant Hepatitis B vaccine is not a live vaccine. The second statement is correct because this vaccine is made by cloning the Hepatitis B antigen gene in yeast. This process uses genetic engineering to make a safe vaccine without using the whole virus.

🎯 Exam Tip: Remember that recombinant vaccines often use only parts of a pathogen, not the whole live organism, to trigger an immune response.

 

Question 4. Statement 1: ADA deficiency was the first disease treated by gene therapy. Statement 2: ADA is an autosomal recessive metabolic disorder.
(a) Statement 4 is true. Statement 2 is false.
(b) Statement 1 is false. Statement 2 is true.
(c) Both statements 1 and 2 are true.
(d) Both statements 1 and 2 are false.
Answer: (c) Both statements 1 and 2 are true.
In simple words: Both statements are correct. Gene therapy was first used for ADA deficiency, which is a genetic problem passed down through families. Gene therapy aims to fix the root cause of such diseases by correcting faulty genes.

🎯 Exam Tip: Knowing the first successful application of a technique like gene therapy can help you recall key historical milestones in biotechnology.

 

Question 5. Statement 1: Attenuated recombinant vaccines are live vaccines. Statement 2: Polio is a live vaccine.
(a) Statement 1 is true. Statement 2 is false.
(b) Statement 1 is false. Statement 2 is true.
(c) Both statements 1 and 2 are true.
(d) Both statements 1 and 2 are false.
Answer: (c) Both statements 1 and 2 are true.
In simple words: Both statements are accurate. Attenuated vaccines use weakened germs that are still alive, and the polio vaccine is one such example. These types of vaccines usually create a very strong and long-lasting immune response.

🎯 Exam Tip: Distinguish between "live attenuated" and "inactivated" vaccines, as this difference is important for understanding how they work and their safety profiles.

 

Question 6. Assertion (A): Interferons are used to treat herpes zoster. Reason (R): Interferons are antiviral proteins.
(a) R explains A.
(b) Both A and Rare incorrect.
(c) A is correct. R is incorrect.
(d) A and R are correct. R does not explain A.
Answer: (a) R explains A.
In simple words: The reason is correct because interferons are proteins that fight viruses, which explains why they are used to treat herpes zoster, a viral infection. Interferons act as messengers that tell other cells to defend themselves against viruses.

🎯 Exam Tip: In assertion-reason questions, first check if both statements are true, then if the reason correctly explains the assertion.

 

Question 7. Assertion (A): PCR is an amplification technique used biotechnology. Reason (R): Using PCR multiple copies of DNA can be generated.
(a) R explains A.
(b) Both A and Rare incorrect.
(c) A is correct. R is incorrect.
(d) A and R are correct. R does not explain A.
Answer: (a) R explains A.
In simple words: The reason correctly explains the assertion. PCR is a biotech method used to make many copies of DNA, which is called amplification. This technique is very helpful in forensics and medical diagnostics when only a small amount of DNA is available.

🎯 Exam Tip: Understand that "amplification" in PCR directly refers to the generation of multiple copies of DNA, making the reason a direct explanation of the assertion.

 

Question 8. The B-chain of Insulin is composed of .................... amino acids
(a) 70
(b) 30
(c) 45
(d) 60
Answer: (b) 30
In simple words: The B-chain part of insulin, which is a protein, is made up of 30 amino acids. Insulin is crucial for regulating blood sugar levels in the body.

🎯 Exam Tip: Knowing the specific number of amino acids in the insulin chains is a common factual detail asked in exams.

 

Question 9. The gene for the formation of factor VIII is located in ....................
(a) 20th Chromosome
(b) 12th Chromosome
(c) X-chromosome
(d) Y-chromosome
Answer: (c) X-chromosome
In simple words: The gene needed to make Factor VIII, which helps blood clot, is found on the X-chromosome. This is why bleeding disorders related to Factor VIII often affect males more commonly.

🎯 Exam Tip: Recall that X-linked inheritance patterns can explain why certain genetic conditions are more prevalent in one sex over the other.

 

Question 10. The genetic defect in the synthesis of factor VIII results in............
(a) Polycythemia
(b) Anaemia
(c) Thalassemia
(d) Haemophilia
Answer: (d) Haemophilia
In simple words: When there is a problem making Factor VIII, it leads to a condition called Haemophilia, which causes issues with blood clotting. Haemophilia is a genetic disorder where the blood does not clot properly, leading to prolonged bleeding.

🎯 Exam Tip: Connect specific genetic defects to their resulting diseases to ensure accurate answers in questions about medical conditions.

 

Question 11. Name the scientists who discovered Interferons?
Answer: Interferons, which are important proteins that fight viruses, were found by two scientists named Alick Issac and Jean Lindemann.
In simple words: Interferons, which are important proteins that fight viruses, were found by two scientists named Alick Issac and Jean Lindemann. Their discovery opened new avenues for antiviral therapies and understanding immune responses.

🎯 Exam Tip: For discovery-based questions, accurately recall both the name of the scientists and what they discovered.

 

Question 12. Which is the first synthetic vaccine produced?
(a) Polio Vaccine
(b) Hepatitis B Vaccine
(c) BCG Vaccine
(d) MMR Vaccine
Answer: (b) Hepatitis B Vaccine
In simple words: The Hepatitis B vaccine was the first vaccine made using synthetic methods in a lab. Synthetic vaccines are often safer because they don't contain any live or dead pathogens, only specific parts.

🎯 Exam Tip: Note the difference between traditional vaccines (using whole pathogens) and synthetic/recombinant vaccines (using specific components).

 

Question 13. Identify the incorrect statement.
(i) The first clinical gene therapy was given by French Anderson.
(ii) For a four-year-old boy with ADA deficiency.
(iii) ACD is an autosomal dominant metabolic disorder.
(iv) Where patients have non-functioning B – lymphocytes.
(a) i and iv only
(b) ii, iii and iv
(c) i, ii and iv
(d) all the above
Answer: (b) ii, iii and iv
In simple words: The incorrect statements are (ii), (iii), and (iv). The first gene therapy was not for a four-year-old boy, ADA deficiency is recessive (not dominant), and B-lymphocytes are not mentioned as the primary problem. Gene therapy targets specific genetic defects to restore normal bodily functions.

🎯 Exam Tip: When identifying incorrect statements, carefully analyze each option for factual accuracy, especially regarding details like age, inheritance patterns, and specific cell types involved.

 

Question 14. Identify the correct statement(s).
(i) Totipotency is the ability of single cell to produce a whole organism.
(ii) Pluripotency refers to ability of stem cell with apotential to differentiate into any kind of germ layers.
(iii) Unipotency refers to ability of stem cell to differentiate into one cell type.
(iv) Oligopotency refers to stem cells to differentiate into few cell types.
(a) i and iii (b) ii and iv (c) i and iv (d) all the above
Answer: (d) all the above
In simple words: All the statements are correct definitions of different stem cell abilities: totipotency (whole organism), pluripotency (all germ layers), unipotency (one cell type), and oligopotency (few cell types). These varying capabilities make stem cells valuable for regenerative medicine and research.

🎯 Exam Tip: Clearly understanding the terms totipotency, pluripotency, multipotency, and unipotency is crucial for questions on stem cells and development.

 

Question 15. Identify those proper sequence of ELISA testing.
(a) Coating → Blocking → Detection → Read out
(b) Detection → Read out → Coating → Blocking
(c) Read out→ Coating → Detection → Blocking
(d) Blocking → Detection → Read out → Coating
Answer: (a) Coating → Blocking → Detection → Read out
In simple words: The correct steps for an ELISA test are coating, then blocking, followed by detection, and finally reading the results. ELISA is a powerful diagnostic tool used to find antibodies or antigens in a sample, helping detect diseases early.

🎯 Exam Tip: Memorize the sequence of steps for common laboratory techniques like ELISA, as procedure order is frequently tested.

 

Question 16. PCR technique was developed by
(a) Eva Engvall
(b) Peter Perlmanin
(c) Kary Mullis
(d) Wilmut
Answer: (c) Kary Mullis
In simple words: The PCR technique, which is used to make many copies of DNA, was invented by Kary Mullis. His innovation revolutionized molecular biology research and diagnostics.

🎯 Exam Tip: Associate key scientific techniques with their discoverers to easily recall such facts.

 

Question 17. Arrange the steps of PCR in proper sequence.
(a) Denaturation, Primer extension, Renaturation
(b) Renaturation, Denaturation, Primer extension
(c) Primer extension, Denaturation, Renaturation
(d) Denaturation, Renaturation, Primer extension
Answer: (d) Denaturation, Renaturation, Primer extension
In simple words: The correct order for PCR steps is denaturation (separating DNA strands), renaturation (primers binding), and then primer extension (new DNA synthesis). Each cycle doubles the amount of DNA, allowing for rapid amplification of a specific gene sequence.

🎯 Exam Tip: Understand the purpose of each PCR step – denaturation to separate, renaturation (annealing) for primers to bind, and extension to synthesize new strands.

 

Question 18. The first cloned organism was.............
(a) Goat
(b) Cow
(c) Sheep
(d) Pig
Answer: (c) Sheep
In simple words: The first organism that was successfully cloned was a sheep. This famous cloned sheep was named Dolly.

🎯 Exam Tip: Remember that Dolly the sheep was the first mammal cloned from an adult somatic cell.

 

Question 19. The first transgenic clone of sheep was called as ....................
(a) Rosie
(b) Dolly
(c) Sameera
(d) Joel
Answer: (b) Dolly
In simple words: The first cloned sheep was named Dolly. Dolly's creation proved that adult cells could be reprogrammed to create a whole new organism.

🎯 Exam Tip: Accurately associating "Dolly" with the first cloned sheep is a key piece of knowledge in biotechnology.

 

Question 20. In the cloning process of Dolly, how many embryos were implemented by Ian Wilmut and Campbell, out of which one successful Dolly was developed?
(a) 267
(b) 211
(c) 287
(d) 307
Answer: (b) 277
In simple words: During the cloning of Dolly, many embryos were created and implanted. Out of all these, only one attempt was successful, leading to the birth of Dolly. This experiment highlighted both the complexity and potential of reproductive cloning techniques.

🎯 Exam Tip: Pay attention to statistics related to scientific breakthroughs, as they often illustrate the challenges and efforts involved.

 

Question 21. The term Biotechnology was coined by..............
Answer: The word "Biotechnology," which describes using living things to make products, was first used by a person named Karl Ereky. He used the term to describe the process of using raw materials to produce proteins with the help of living organisms.
In simple words: The word "Biotechnology," which describes using living things to make products, was first used by a person named Karl Ereky. He used the term to describe the process of using raw materials to produce proteins with the help of living organisms.

🎯 Exam Tip: Knowing the origin of scientific terms can provide useful context and help in understanding the field.

 

12th Bio Zoology Guide Applications of Biotechnology Two Marks Questions and Answers

 

Question 1. How insulin controls blood sugar level?
Answer: Insulin helps control blood sugar by making body cells take in glucose from the blood and use it for energy. This process prevents blood sugar from getting too high, which is essential for health.
In simple words: Insulin helps control blood sugar by making body cells take in glucose from the blood and use it for energy. This process prevents blood sugar from getting too high, which is essential for health.

🎯 Exam Tip: Clearly state that insulin promotes glucose uptake by cells, which is its primary mechanism for lowering blood sugar.

 

Question 2. State the role of Somatostatin and Somatotropin in human beings.
Answer: Somatostatin and somatotropin are hormones that help with growth and body development. They do this by helping cells take in more amino acids and make more proteins. Somatotropin is also known as growth hormone, which directly influences the growth of bones and tissues.
In simple words: Somatostatin and somatotropin are hormones that help with growth and body development. They do this by helping cells take in more amino acids and make more proteins.

🎯 Exam Tip: Distinguish between the functions of somatostatin (inhibitory) and somatotropin (stimulatory, growth hormone) when detailing their roles.

 

Question 3. Mention the manifestation of the disease – Haemophilia-A
Answer: Haemophilia A is a genetic disease found on the X-chromosome. It causes blood to take a long time to clot and can lead to bleeding inside the body. Even small injuries can be dangerous for individuals with haemophilia due to uncontrolled bleeding.
In simple words: Haemophilia A is a genetic disease found on the X-chromosome. It causes blood to take a long time to clot and can lead to bleeding inside the body.

🎯 Exam Tip: When describing disease manifestations, include both the primary symptom (prolonged clotting) and its significant consequence (internal bleeding).

 

Question 4. Define Interferons.
Answer: Interferons are proteins made by cells in mammals when a virus infects them. These proteins help the body fight off viruses by telling other cells to make enzymes that stop viruses from multiplying, thus protecting the cells. They are a crucial part of the body's natural immune defense against viral infections.
In simple words: Interferons are proteins made by cells in mammals when a virus infects them. These proteins help the body fight off viruses by telling other cells to make enzymes that stop viruses from multiplying, thus protecting the cells.

🎯 Exam Tip: Emphasize that interferons are "antiviral proteins" and their role is to "inhibit viral replication" in other cells.

 

Question 5. Who discovered Interferons? On which basis it was classified?'
Answer: Interferons were found by Alick Isaacs and Jean Lindemann in 1957. They are grouped into alpha, beta, and gamma types based on what they are made of (their structure). This classification helps scientists understand their specific functions and applications in medicine.
In simple words: Interferons were found by Alick Isaacs and Jean Lindemann in 1957. They are grouped into alpha, beta, and gamma types based on what they are made of (their structure).

🎯 Exam Tip: When asked about discoveries and classifications, provide both the names of the discoverers and the basis for classification clearly.

 

Question 6. Name the disease that are treated by using interferons.
Answer: Interferons are used to treat several diseases, including cancer, AIDS, multiple sclerosis, hepatitis C, and herpes zoster. Their antiviral and immune-modulating properties make them effective against a range of health conditions.
In simple words: Interferons are used to treat several diseases, including cancer, AIDS, multiple sclerosis, hepatitis C, and herpes zoster.

🎯 Exam Tip: Focus on naming a diverse set of diseases (viral, autoimmune, cancer) to show a comprehensive understanding of interferon applications.

 

Question 7. Recombinant vaccines are better than conventional ones – Justify.
Answer: Recombinant vaccines are better than older vaccines because they are made in a more consistent way, meaning they are always of high quality. They also cause fewer bad reactions in people compared to traditional vaccines. This improved safety and consistency result from using specific parts of a pathogen instead of the whole organism.
In simple words: Recombinant vaccines are better than older vaccines because they are made in a more consistent way, meaning they are always of high quality. They also cause fewer bad reactions in people compared to traditional vaccines.

🎯 Exam Tip: Key justifications for recombinant vaccines' superiority include "uniform quality," "fewer side effects," and "specific antigen targeting."

 

Question 8. Point out four types of recombinant vaccines.
Answer:
1. Subunit recombinant vaccines
2. Attenuated recombinant vaccines
3. Edible vaccines
4. DNA vaccines
In simple words: Four kinds of recombinant vaccines are: subunit vaccines (using parts of the germ), attenuated vaccines (using weakened germs), edible vaccines (grown in plants), and DNA vaccines (using genetic material). Each type offers unique advantages in how immunity is developed and delivered.

🎯 Exam Tip: Be ready to list and briefly describe the distinct categories of recombinant vaccines to demonstrate a thorough understanding.

 

Question 9. What are subunit recombinant vaccines? Mention its advantages.
Answer: Subunit recombinant vaccines use only a small part of a disease-causing germ, not the whole germ. The good things about these vaccines are that they are very pure, stay effective for a long time, and are safe to use. This approach avoids any risk of the vaccine causing the disease itself, as it only uses non-infectious fragments.
In simple words: Subunit recombinant vaccines use only a small part of a disease-causing germ, not the whole germ. The good things about these vaccines are that they are very pure, stay effective for a long time, and are safe to use.

🎯 Exam Tip: When defining subunit vaccines, highlight the use of isolated antigenic components and link this directly to their advantages in terms of purity and safety.

 

Question 10. Define Attenuated recombinant vaccines.
Answer: Attenuated recombinant vaccines are made from disease-causing germs (like bacteria or viruses) that have been changed through genetic engineering to become harmless. These weakened but still living germs are then used as vaccines. They mimic natural infection, often providing strong and long-lasting immunity.
In simple words: Attenuated recombinant vaccines are made from disease-causing germs (like bacteria or viruses) that have been changed through genetic engineering to become harmless. These weakened but still living germs are then used as vaccines.

🎯 Exam Tip: The key characteristic of attenuated vaccines is that they use a "weakened" (non-pathogenic) but "live" form of the organism to elicit immunity.

 

Question 11. List out the benefits of recombinant vaccines.
Answer: Recombinant vaccines offer clear benefits: they can make specific proteins that fight disease, provide immunity that lasts a long time, and cause the body to react only to the specific germ, with fewer harmful side effects. This targeted approach minimizes unwanted reactions while effectively preparing the immune system.
In simple words: Recombinant vaccines offer clear benefits: they can make specific proteins that fight disease, provide immunity that lasts a long time, and cause the body to react only to the specific germ, with fewer harmful side effects.

🎯 Exam Tip: Focus on the advantages unique to recombinant technology, such as targeted immunity and reduced toxicity, compared to older vaccine types.

 

Question 12. Name the two strategies involved in gene therapy
Answer:
1. Gene augmentation therapy.
2. Gene inhibition therapy.
In simple words: The two main ways gene therapy works are by adding missing genes (gene augmentation therapy) or by stopping harmful genes from working (gene inhibition therapy). These strategies aim to correct genetic problems at their source, offering potential cures for inherited diseases.

🎯 Exam Tip: Clearly distinguish between augmentation (adding a functional gene) and inhibition (suppressing a faulty gene) as the core strategies of gene therapy.

 

Question 13. Comment on SCID.
Answer: SCID, also known as ADA deficiency, is a serious genetic disorder where a child's immune system doesn't work well. It happens when a gene that makes the ADA enzyme is missing or faulty. Because of this, the body's T-lymphocytes can't fight off germs, leaving the patient very vulnerable to infections. This condition makes affected children highly susceptible to even common illnesses, requiring extreme protective measures.
In simple words: SCID, also known as ADA deficiency, is a serious genetic disorder where a child's immune system doesn't work well. It happens when a gene that makes the ADA enzyme is missing or faulty. Because of this, the body's T-lymphocytes can't fight off germs, leaving the patient very vulnerable to infections.

🎯 Exam Tip: When discussing SCID, remember to mention its genetic cause (ADA deficiency) and its primary impact (non-functional T-lymphocytes, leading to severe immunodeficiency).

 

Question 14. Differentiate between Gene augmentation therapy and gene inhibition therapy.
Answer: Gene augmentation therapy adds new, working DNA into a person's cells to replace a missing gene or its product. Gene inhibition therapy, on the other hand, puts in a special gene (called anti-sense gene) that stops a harmful, dominant gene from working. Both therapies offer distinct methods to tackle genetic diseases, either by adding a missing function or by suppressing a harmful one.
In simple words: Gene augmentation therapy adds new, working DNA into a person's cells to replace a missing gene or its product. Gene inhibition therapy, on the other hand, puts in a special gene (called anti-sense gene) that stops a harmful, dominant gene from working.

🎯 Exam Tip: Clearly state the goal of each therapy: augmentation aims to add function, while inhibition aims to reduce or stop harmful function.

 

Question 15. Define the terms (a) Totipotency (b) Unipotency
Answer:
(a) Totipotency means a single cell can grow into a complete organism, including all its different cell types.
(b) Unipotency means a stem cell can only turn into one specific type of cell.
In simple words: (a) Totipotency means a single cell can grow into a complete organism, including all its different cell types. (b) Unipotency means a stem cell can only turn into one specific type of cell. These terms describe the different levels of developmental flexibility that stem cells possess.

🎯 Exam Tip: Differentiate these terms by the range of cell types a cell can differentiate into: "total" for totipotency vs. "one" for unipotency.

 

Question 16. What are the best sources of stem cells in mammals?
Answer: In mammals, good places to get stem cells are the placenta, umbilical cord, amniotic sac, and the fluid around the baby (amniotic fluid). These sources are often preferred because they are easily accessible and ethically less controversial than embryonic stem cells.
In simple words: In mammals, good places to get stem cells are the placenta, umbilical cord, amniotic sac, and the fluid around the baby (amniotic fluid).

🎯 Exam Tip: Focus on readily available and ethically acceptable sources of stem cells for medical applications.

 

Question 17. Write the names of any two molecular diagnostic techniques used for early diagnosis of diseases?
Answer:
(a) Polymerase Chain Reaction (PCR) technique.
(b) Enzyme Linked Immuno Sorbent Assay (ELISA)
In simple words: Two important methods for finding diseases early at a molecular level are the Polymerase Chain Reaction (PCR) and the Enzyme-Linked Immunosorbent Assay (ELISA). These techniques allow doctors to detect disease-causing agents or specific markers with high sensitivity.

🎯 Exam Tip: PCR and ELISA are fundamental techniques in molecular diagnostics, so know their full names and basic applications.

 

Question 18. What does ELISA stands for? Who invented this technique?
Answer: ELISA stands for Enzyme-Linked Immunosorbent Assay. This testing method was created by Eva Engvall and Peter Perlman. ELISA is widely used to detect antibodies, antigens, or hormones in a sample, helping diagnose various conditions.
In simple words: ELISA stands for Enzyme-Linked Immunosorbent Assay. This testing method was created by Eva Engvall and Peter Perlman.

🎯 Exam Tip: For acronyms, provide the full form and credit the inventors to score full marks.

 

Question 19. Name the various kinds of ELISA.
Answer: There are four main types of ELISA tests: Direct ELISA, Indirect ELISA, sandwich ELISA, and competitive ELISA. Each type uses a slightly different approach to achieve high sensitivity and specificity in detecting targets.
In simple words: There are four main types of ELISA tests: Direct ELISA, Indirect ELISA, sandwich ELISA, and competitive ELISA.

🎯 Exam Tip: Listing the different types of ELISA shows a detailed understanding of the technique's variations.

 

Question 20. Simply define the PCR technique. Also mention its inventor.
Answer: PCR, or Polymerase Chain Reaction, is a lab method used to make many identical copies of a specific piece of DNA. It can create billions of copies. This technique was invented by Kary Mullis in 1983. PCR is incredibly valuable for genetic testing, forensic analysis, and scientific research because it can amplify even tiny amounts of DNA.
In simple words: PCR, or Polymerase Chain Reaction, is a lab method used to make many identical copies of a specific piece of DNA. It can create billions of copies. This technique was invented by Kary Mullis in 1983.

🎯 Exam Tip: Define PCR by its function (DNA amplification) and identify its inventor, Kary Mullis.

 

Question 21. Expand PCR and name the steps involved in the process.
Answer: PCR stands for Polymerase Chain Reaction. The three main steps in this technique are denaturation (separating DNA strands), renaturation (primers attaching), and primer extension (building new DNA). Each cycle of these three steps exponentially increases the amount of target DNA.
In simple words: PCR stands for Polymerase Chain Reaction. The three main steps in this technique are denaturation (separating DNA strands), renaturation (primers attaching), and primer extension (building new DNA).

🎯 Exam Tip: Provide the full form of PCR and list the three distinct steps in their correct order: denaturation, renaturation/annealing, and extension.

 

Question 22. For which disease does the first clinical gene therapy was done? Who accomplished it?
Answer: The first time gene therapy was used in a clinic was to treat SCID, or Severe Combined Immunodeficiency disease. This disease is caused by a lack of the ADA enzyme. French Anderson carried out this first successful treatment in 1990. This landmark achievement offered hope for permanent cures for many other genetic disorders.
In simple words: The first time gene therapy was used in a clinic was to treat SCID, or Severe Combined Immunodeficiency disease. This disease is caused by a lack of the ADA enzyme. French Anderson carried out this first successful treatment in 1990.

🎯 Exam Tip: Remember the specific disease (SCID), its cause (ADA deficiency), and the scientist (French Anderson) for the first clinical gene therapy.

 

Question 23. Define Transgenesis.
Answer: Transgenesis is the method of adding extra DNA from a different source into an organism's genetic material. The goal is to make the organism develop and keep new traits that can be passed on to its offspring. This technique is fundamental to creating genetically modified organisms with desired characteristics.
In simple words: Transgenesis is the method of adding extra DNA from a different source into an organism's genetic material. The goal is to make the organism develop and keep new traits that can be passed on to its offspring.

🎯 Exam Tip: Key terms for defining transgenesis are "introduction of foreign DNA" and "stable heritable characters."

 

Question 24. What are the Genetically Modified Organisms?
Answer: Genetically Modified Organisms (GMOs) are living things that have had foreign DNA added to their genetic material through a process called transgenesis. This added DNA, known as a transgene, gives them new, stable traits that can be passed down. These organisms are also called transgenic animals or genetically engineered organisms. GMOs are used in various fields, from agriculture to medicine, to improve traits or produce valuable substances.
In simple words: Genetically Modified Organisms (GMOs) are living things that have had foreign DNA added to their genetic material through a process called transgenesis. This added DNA, known as a transgene, gives them new, stable traits that can be passed down.

🎯 Exam Tip: Link GMOs directly to the process of transgenesis and the concept of introducing a "transgene" to create new heritable traits.

 

Question 25. What does Biological Product refers to?
Answer: A biological product is something that comes from a living organism and is used to stop or treat diseases. Examples include medicines like antitoxins, vaccines (for bacteria and viruses), parts of blood, and hormones. These products are essential in modern medicine for both preventing and managing various health conditions.
In simple words: A biological product is something that comes from a living organism and is used to stop or treat diseases. Examples include medicines like antitoxins, vaccines (for bacteria and viruses), parts of blood, and hormones.

🎯 Exam Tip: Define biological products by their origin (living organisms) and their application (prevention or treatment of disease), along with common examples.

 

Question 26. Define cloning. Name the first organism developed by cloning.
Answer: Cloning is the process of making exact genetic copies of an organism, either naturally or in a lab. The first animal successfully cloned was a sheep, which was named Dolly. Dolly's birth in 1996 marked a significant milestone in the field of genetic engineering.
In simple words: Cloning is the process of making exact genetic copies of an organism, either naturally or in a lab. The first animal successfully cloned was a sheep, which was named Dolly.

🎯 Exam Tip: In your definition of cloning, include both natural and artificial processes and accurately name the first cloned organism (Dolly the sheep).

 

Question 27. Who developed Dolly? How many embryos were aborted to develop a single Dolly?
Answer: Dolly, the first cloned sheep, was developed by scientists Ian Wilmut and Campbell. To create her, 29 embryos were implanted, but only one successfully developed into Dolly. This highlights the significant challenges and low success rates often associated with early cloning experiments.
In simple words: Dolly, the first cloned sheep, was developed by scientists Ian Wilmut and Campbell. To create her, 29 embryos were implanted, but only one successfully developed into Dolly.

🎯 Exam Tip: Be precise with the names of the scientists (Ian Wilmut and Campbell) and the number of attempts (29 embryos, 1 success) for Dolly's creation.

 

Question 28. Define Biotechnology.
Answer: Biotechnology is the use of living systems, organisms, or their parts to create or change products and processes for specific purposes. This broad field encompasses everything from brewing beer to developing advanced medical therapies.
In simple words: Biotechnology is the use of living systems, organisms, or their parts to create or change products and processes for specific purposes.

🎯 Exam Tip: A good definition of biotechnology should include "biological systems/living organisms" and their application to "make or modify products/processes."

 

12th Bio Zoology Guide Applications of Biotechnology Three Marks Questions and Answers

 

Question 29. Briefly explain the structure of insulin.
Answer: Human insulin is made in the pancreas and has 51 amino acids. These are arranged into two parts: Chain A with 21 amino acids and Chain B with 30 amino acids. These two chains are held together by special links called disulfide bonds. This specific structure is crucial for insulin to function correctly in regulating blood sugar.
In simple words: Human insulin is made in the pancreas and has 51 amino acids. These are arranged into two parts: Chain A with 21 amino acids and Chain B with 30 amino acids. These two chains are held together by special links called disulfide bonds.

🎯 Exam Tip: Focus on the two polypeptide chains (A and B), their respective amino acid counts, and the disulfide bonds connecting them as key structural details.

 

Question 30. Who was the first to discover the role of insulin against diabetes? From which organism does was insulin isolated?
Answer: In 1921, Best and Banting were the first to discover that insulin could help manage diabetes. They took insulin from the pancreas of a dog to show how it worked. Their groundbreaking work led to the first effective treatment for diabetes, saving countless lives.
In simple words: In 1921, Best and Banting were the first to discover that insulin could help manage diabetes. They took insulin from the pancreas of a dog to show how it worked.

🎯 Exam Tip: Credit Best and Banting for the discovery of insulin's role and remember the dog as the source organism for their initial isolation.

 

Question 31. How "Rosie" differs from a normal cow? Explain.
Answer: Rosie was special because she was the first genetically modified cow to produce milk containing human proteins. Her milk had human alpha-lactalbumin, making it more nutritious for human babies than regular cow's milk. This achievement demonstrated the potential of biotechnology to enhance the nutritional value of agricultural products.
In simple words: Rosie was special because she was the first genetically modified cow to produce milk containing human proteins. Her milk had human alpha-lactalbumin, making it more nutritious for human babies than regular cow's milk.

🎯 Exam Tip: Highlight Rosie's unique trait: producing human protein-enriched milk, making it nutritionally superior for infants compared to normal cow's milk.

 

Question 32. Point out any two microbes that play a crucial role in recombinant DNA
Answer:
1. Saccharomyces cerevisiae
2. Escherichia coli
In simple words: Two microbes that are very important in recombinant DNA technology are Saccharomyces cerevisiae (a type of yeast) and Escherichia coli (a type of bacteria). These microorganisms are commonly used as "factories" to produce various proteins and other biotechnology products.

🎯 Exam Tip: Common microbial hosts like E. coli and Saccharomyces cerevisiae are fundamental to recombinant DNA technology, so remember their names.

 

Question 33. What are Edible vaccines?
Answer: Edible vaccines are made using genetic engineering, a process called molecular pharming. Specific genes are put into plants, which then produce the desired protein. These vaccines are designed to activate both the body's overall immune system and the immune response in the mucous membranes. They offer a safe and easy way to deliver vaccines.
In simple words: Edible vaccines are like regular food items, such as fruits or vegetables, that have been changed using genetic science to make our bodies strong against diseases.

🎯 Exam Tip: Remember that edible vaccines offer advantages like easier administration and storage compared to traditional injectable vaccines.

 

Question 34. How the recombinant hepatitis B vaccine is produced in the laboratory?
Answer: The recombinant hepatitis B vaccine is a subunit vaccine. It is made in the laboratory by taking the gene for the hepatitis B surface antigen (HbsAg) and inserting it into yeast cells, specifically `\( Saccharomyces\ cerevisiae \)`. These yeast cells then produce large amounts of the HbsAg protein, which is collected and used as the vaccine. This method ensures the vaccine is safe and effective.
In simple words: Scientists make the hepatitis B vaccine by putting a part of the virus's DNA into yeast. The yeast then grows this part of the virus, which is used to create the vaccine that teaches our body to fight the real virus.

🎯 Exam Tip: Note that `\( Saccharomyces\ cerevisiae \)` (brewer's yeast) is a common and safe host organism used in biotechnology for producing proteins like vaccine components.

 

Question 35. Suggest few methods to treat SCID.
Answer: SCID, which is caused by ADA deficiency, can be treated in a few ways. One method is bone marrow transplantation, where healthy immune cells from a donor replace the patient's faulty immune cells. Another treatment is enzyme replacement therapy, where the patient receives injections of functional ADA to break down harmful substances. Gene therapy, introducing a correct gene, offers a permanent cure if done at an early embryonic stage.
In simple words: SCID can be treated by giving healthy bone marrow, giving enzyme shots, or by gene therapy, which tries to fix the problem permanently.

🎯 Exam Tip: Distinguish between temporary (enzyme replacement) and potentially permanent (gene therapy, bone marrow transplant) solutions for genetic disorders like SCID.

 

Question 36. How gene therapy is done to treat ADA deficiency?
Answer: To treat ADA deficiency with gene therapy, lymphocytes (a type of immune cell) are taken from the patient's blood. These cells are then grown in a special lab dish. A healthy, working human gene for ADA is put into these lymphocytes using a retrovirus, which acts as a carrier. The genetically modified lymphocytes are then put back into the patient. Since these cells don't live forever, the patient needs regular infusions. A permanent cure can happen if the ADA gene is put into bone marrow cells at a very early stage of development.
In simple words: Gene therapy for ADA deficiency involves taking out a patient's immune cells, adding a healthy gene to them in the lab, and putting them back. This helps the body make the missing enzyme.

🎯 Exam Tip: Remember that for a permanent cure in gene therapy, the healthy gene must be introduced into stem cells or early embryonic cells that can self-renew and pass on the gene.

 

Question 37. How does Somatic cell therapy differ from germline gene therapy?
Answer: Somatic cell therapy involves putting a working gene into a specific body cell (somatic cell) to fix a genetic disease in that person permanently. This change only affects the treated individual. On the other hand, germline gene therapy involves introducing DNA into reproductive cells (germ cells like sperm or eggs). This means the changes will be passed on to future generations. Somatic therapy focuses on the patient, while germline therapy aims to prevent the disease in offspring.
In simple words: Somatic cell therapy changes genes in body cells, helping only the person treated. Germline therapy changes genes in reproductive cells, so the changes can be passed to children.

🎯 Exam Tip: A key difference is inheritability; somatic cell therapy effects are not inherited, while germline therapy effects are.

 

Question 38. Differentiate between Pluripotency and Multipotency.
Answer: Pluripotency means a stem cell has the ability to turn into any type of cell that comes from the three main germ layers of an embryo (ectoderm, endoderm, and mesoderm). However, it cannot form a complete organism on its own because it cannot create the tissues needed for embryonic development. Multipotency refers to stem cells that can differentiate into various types of cells, but only within a specific lineage or tissue type. For example, blood stem cells can become different types of blood cells. So, pluripotent cells have a wider range of differentiation potential than multipotent cells.
In simple words: Pluripotent cells can become almost any cell type in the body, while multipotent cells can only become different cell types within one family, like all kinds of blood cells.

🎯 Exam Tip: Remember that a truly "totipotent" cell (like a zygote) can form a whole organism, while pluripotent cells have a very broad, but not complete, differentiation capacity.

 

Question 39. Write a short note on stem cell banks.
Answer: Stem cell banking involves collecting, processing, and storing stem cells for potential future medical treatments. Amniotic cell banks are places that store stem cells from amniotic fluid. These cells are kept for the individual they were collected from, and storage costs are paid. Umbilical cord blood is a very popular source of stem cells, collected during childbirth. The placenta, amniotic sac, and amniotic fluid are also good sources of these valuable cells, making stem cell banking a critical resource for future medical needs.
In simple words: Stem cell banks store special cells from sources like umbilical cord blood or amniotic fluid. These stored cells can be used later to treat diseases or repair damaged body parts.

🎯 Exam Tip: Focus on the purpose (future treatment) and common sources (umbilical cord blood, amniotic fluid) when describing stem cell banks.

 

Question 40. State any two uniqueness of the ELISA test.
Answer: The ELISA test is very sensitive and can find even tiny amounts of antigens, down to nanograms. This high sensitivity makes it useful for detecting diseases early. Also, the ELISA test does not need radioactive materials or special radiation counting machines, unlike some other tests. It uses enzymes and color changes instead, making it safer and easier to perform in many labs.
In simple words: ELISA is special because it can find very small amounts of disease markers, and it does not use harmful radiation like some other tests.

🎯 Exam Tip: Highlight both sensitivity (detects small amounts) and safety (no radioisotopes) as key advantages of ELISA.

 

Question 41. What is the ELISA test?
Answer: ELISA stands for Enzyme-Linked ImmunoSorbent Assay. It is a biological test that finds specific antibodies, antigens, or hormones in a sample, such as blood serum or urine. This test uses special enzymes that create a color change when a target substance is present, helping doctors diagnose infections or other conditions. It is a widely used and important diagnostic tool.
In simple words: ELISA is a test that uses enzymes to find certain things like infection-fighting antibodies, germs, or hormones in a person's body fluid, usually by a color change.

🎯 Exam Tip: Remember the full form of ELISA and its basic function: detecting specific biological markers using enzyme-linked reactions.

 

Question 42. Elucidate the methodology of the ELISA test.
Answer: During an ELISA test, the sample (like blood) suspected to have the antigen is first attached to a special plate. Then, an antibody that specifically binds to this antigen is added and allowed to react. After washing away any unbound antibody, another antibody, linked to an enzyme like peroxidase, is added. This "anti-antibody" binds to the first antibody. After another wash, a substance called a substrate (like hydrogen peroxidase) is added. This substrate reacts with the enzyme to produce a colored product, which shows that the antigen is present. The intensity of the color indicates the amount of antigen present.
In simple words: In ELISA, the sample is put on a plate, then specific antibodies are added. If the target is there, it sticks. Next, an enzyme-linked antibody is added, and then a color-changing substance. If color appears, the target is present.

🎯 Exam Tip: Keep the steps of ELISA in order: immobilization of antigen, primary antibody binding, enzyme-linked secondary antibody binding, substrate addition, and color development.

 

Question 43. Whether PCR is applicable for RNA molecules? Explain.
Answer: Yes, PCR can be used for RNA molecules. When used for RNA, the technique is called reverse transcription PCR, or RT-PCR. In this process, the RNA molecules (mRNA) are first changed into complementary DNA (cDNA) by an enzyme called reverse transcriptase. Once the RNA is converted to cDNA, this cDNA then acts as the template for the regular PCR process, allowing for the amplification of specific RNA sequences. This method is crucial for studying gene expression.
In simple words: Yes, PCR can work for RNA. First, RNA is changed into DNA using a special enzyme. Then, this new DNA is used in the regular PCR process to make many copies.

🎯 Exam Tip: Differentiate between standard PCR (DNA only) and RT-PCR (RNA converted to cDNA, then amplified), and remember the key enzyme is reverse transcriptase.

 

Question 44. How PCR helps forensic personnel?
Answer: PCR is very helpful in forensic science. Even a tiny amount of DNA, such as from a single hair, a bloodstain, or semen, can be amplified (copied many times) using PCR. This amplified DNA is then used to create a DNA fingerprint, which helps identify criminals or victims. This ability to work with very small samples makes PCR an important tool for solving crimes. PCR also helps in paternity testing.
In simple words: PCR helps forensic teams by making many copies of DNA from tiny samples found at crime scenes, like a single hair. This helps them create DNA fingerprints to identify people.

🎯 Exam Tip: Remember that PCR's ability to amplify minute quantities of DNA is its primary benefit in forensics, enabling DNA fingerprinting from limited samples.

 

Question 45. Role of PCR in phylogenetics. Explain.
Answer: PCR plays a crucial role in phylogenetics, which is the study of evolutionary relationships among different organisms. It allows scientists to compare the genetic differences in the DNA of various organisms. Because PCR can amplify even very small amounts of DNA from sources like hair, old tissues, bones, or fossils, it helps researchers study evolutionary changes over time. This makes it possible to understand how different species are related and how they have evolved.
In simple words: PCR helps scientists study how different living things are related by looking at their DNA. It can make many copies of DNA from even very old or tiny samples, which helps in understanding evolution.

🎯 Exam Tip: Connect PCR's ability to amplify degraded or ancient DNA samples to its utility in tracing evolutionary lineages in phylogenetics.

 

Question 46. Enumerate the use of biological products.
Answer: Biological products have many uses. Antibodies, which fight disease, can be made using transgenic animals that act like bioreactors. Monoclonal antibodies are used to treat cancer, heart disease, and help with organ transplants. Natural protein adhesives are another biological product; they are safe, break down naturally, and rarely cause allergic reactions. These can be used to reattach tendons and tissues, fill cavities in teeth, and help mend broken bones, offering effective medical solutions.
In simple words: Biological products like antibodies help fight diseases and treat conditions like cancer. Natural protein glues can also be used in medicine to repair tissues and bones safely.

🎯 Exam Tip: When discussing biological products, focus on specific examples like antibodies and protein adhesives, and their medical applications rather than general uses.

 

Question 47. Name the principles underlying the cloning technique.
Answer: The main principles behind cloning techniques are nuclear transfer and totipotency. Nuclear transfer involves taking the nucleus from a somatic cell (any body cell other than a reproductive cell) and putting it into an egg cell that has had its own nucleus removed. Totipotency is the ability of a single cell to grow and develop into a complete organism. In cloning, the transplanted nucleus directs the enucleated egg to develop into a new, genetically identical individual.
In simple words: Cloning works by moving the core part (nucleus) from one cell into an empty egg cell, and by using the cell's ability to grow into a whole new organism.

🎯 Exam Tip: Clearly define both nuclear transfer (the technique) and totipotency (the cellular potential) as the foundational principles of cloning.

12th Bio Zoology Guide Applications of Biotechnology Five Marks Questions and Answers

 

Question 48. Explain in detail about stem cell therapy.
Answer: Stem cells are special cells found in most multicellular animals that have not yet differentiated into a specific cell type. They can divide many times while staying undifferentiated. Stem cell research has the potential to change medicine by helping to regenerate damaged or diseased organs. These cells can renew themselves and have "cellular potency," meaning they can become different types of cells. Embryonic stem (ES) cells are pluripotent, capable of forming any cell type from the three germ layers (ectoderm, mesoderm, endoderm), but not a whole organism. Adult stem cells, found in tissues of children and adults, are mostly multipotent, meaning they can develop into several cell types within a specific lineage. They act as a repair system, replenishing tissues; red bone marrow is a rich source. The primary use of human stem cells is to generate cells and tissues for cell-based therapies, and they are also used for testing new drugs safely.
In simple words: Stem cell therapy uses special "blank" cells that can turn into different body parts. These cells can help repair damaged organs and treat diseases, offering new ways to heal the body.

🎯 Exam Tip: When explaining stem cell therapy, include the definition of stem cells, their potency (pluripotent vs. multipotent), their sources, and the potential applications in regenerative medicine and drug testing.

 

Question 49. Describe the role of PCR in clinical field.
Answer: PCR (Polymerase Chain Reaction) is a powerful tool in clinical diagnosis due to its high specificity and sensitivity. It is used to diagnose various inherited disorders (genetic diseases), viral diseases, and bacterial diseases. Often, diagnosing and treating a disease involves finding the specific pathogen. Unlike older methods that require growing organisms in a lab, PCR can directly detect a pathogen's DNA in a clinical sample, such as blood, stool, spinal fluid, or sputum. If the pathogen is present, its unique DNA sequences can be found using PCR. This technique is also used in prenatal diagnosis to detect inherited diseases like sickle cell anemia, thalassemia, and phenylketonuria from chorionic villi samples or amniotic fluid. Additionally, PCR helps detect virally induced cancers (e.g., cervical cancer caused by Papillomavirus) and sex-linked disorders in embryos. It is also valuable for diagnosing and monitoring retroviral infections like tuberculosis.
In simple words: PCR helps doctors find diseases early by looking for specific DNA of germs or genetic problems in a patient's sample, even very tiny amounts. It is used for finding infections, genetic disorders, and even some cancers.

🎯 Exam Tip: Highlight PCR's use in detecting pathogens (viruses, bacteria) and genetic disorders (inherited diseases) from clinical specimens, emphasizing its specificity and sensitivity.

 

Question 50. Enumerate the steps involved in producing transgenic animals.
Answer: Producing transgenic animals involves several key steps. First, the desired gene needs to be identified and separated. Next, a vector (often a virus) is chosen to carry this gene, or direct transmission methods are used. Then, the desired gene is combined with the chosen vector. This engineered vector is then introduced into cells, tissues, an embryo, or a mature individual. Finally, scientists must confirm that the foreign gene has successfully integrated into the animal's DNA and is being expressed. Transgenic animals like mice, rats, rabbits, pigs, cows, goats, sheep, and fish have been successfully produced using these techniques.
In simple words: Making a transgenic animal involves finding a specific gene, putting it into a carrier like a virus, and then adding it to animal cells or an embryo. This makes the animal have new traits from that added gene.

🎯 Exam Tip: List the steps in a clear, sequential manner: gene identification, vector selection, gene-vector combination, introduction into host, and confirmation of integration and expression.

 

Question 51. List out the uses of Transgenesis.
Answer: Transgenesis has many important uses. It is a powerful tool for studying how genes work and how organisms develop. It helps improve genetic traits in animals, such as increasing milk or meat quality. Transgenic animals serve as valuable models for understanding human diseases like cancer, Alzheimer's, cystic fibrosis, rheumatoid arthritis, and sickle cell anemia, which helps in finding new treatments. They are also used to produce important proteins for medical and pharmaceutical uses. Furthermore, transgenic mice are used to test the safety of vaccines and evaluate the toxicity of various substances, as these animals can be made more sensitive to toxins than regular animals.
In simple words: Transgenesis helps us study genes, improve animal traits, understand human diseases, make medicines, and test vaccines or harmful substances.

🎯 Exam Tip: Categorize the uses of transgenesis into research (gene expression, disease models), agricultural improvement, and pharmaceutical production/safety testing.

 

Question 52. Describe the procedure by which Dolly was developed.
Answer: Dolly the sheep, the first cloned mammal, was created in 1997 by Ian Wilmut and Keith Campbell using the nuclear transfer technique, which relies on the principle of totipotency. First, mammary gland cells (somatic cells) were taken from a donor sheep (a Finn-Dorset ewe) and starved for five days to make them totipotent (able to develop into a whole organism). Meanwhile, an unfertilized egg cell was taken from another sheep (a Scottish Blackface ewe), and its nucleus was removed. The nucleus from the mammary gland cell was then transferred into this enucleated egg cell. The fused cell was stimulated to start dividing and was then implanted into a surrogate mother sheep (another Scottish Blackface ewe). After five months, Dolly was born. This showed that a differentiated adult somatic cell could be used to create an entire organism without fertilization.
In simple words: Dolly was made by taking a cell from one sheep, removing its nucleus, and putting it into an egg cell from another sheep that had its nucleus removed. This new cell was then grown in a third sheep and became Dolly, a perfect clone.

🎯 Exam Tip: Key elements to include are the donor cell (mammary gland), recipient egg (enucleated), technique (nuclear transfer), and the concept of totipotency, mentioning Ian Wilmut and Campbell.

 

Question 53. What are the ethical issues about cloning.
Answer: Biotechnology has brought many benefits like cheaper drugs and better crops, but genetic manipulations, including cloning, raise significant ethical concerns. A major fear is that these changes might lead to unknown or harmful outcomes. Many people worry about the potential for creating new, dangerous microorganisms, either by accident or on purpose, which could cause epidemics or environmental disasters. There are also concerns about animal suffering during cloning attempts, as many attempts fail, and cloned animals often have health issues and shorter lifespans. Some activists also view animal and human cloning as a threat to biodiversity and evolution, arguing it could impact populations and ecosystems by interfering with natural processes.
In simple words: Cloning brings up ethical problems like unknown dangers from changing genes, possible suffering for cloned animals, and worries that it might harm natural evolution or create new harmful organisms.

🎯 Exam Tip: Focus on the risks and societal concerns: unknown consequences, potential for harm (animals, environment), and impact on biodiversity/evolution.

Higher Order Thinking Skills (HOTs) Questions

 

Question 1. The immune system of a person is suppressed. In ELISA test, the result is positive.
(i) Name the disease associated with this.
(ii) Why did he loose his immunity?
Answer:
(i) The disease associated with a suppressed immune system and a positive ELISA test is AIDS (Acquired Immunodeficiency Syndrome).
(ii) A person with AIDS loses immunity because the Human Immunodeficiency Virus (HIV), which causes AIDS, directly attacks and destroys T-lymphocytes. T-lymphocytes are a crucial part of the immune system that help fight off infections. When these cells are destroyed, the body can no longer defend itself effectively against various pathogens, leading to a weakened immune system.
In simple words: The disease is AIDS. The person loses immunity because the HIV virus attacks and kills the T-lymphocytes, which are important cells that fight off sickness in the body.

🎯 Exam Tip: For this question, clearly state AIDS as the disease and explain the mechanism of immune suppression by HIV targeting T-lymphocytes.

 

Question 2. Why do children cured by enzyme replacement therapy for ADA deficiency need periodic treatment? Suggest a permanent solution for this issue.
Answer: Children treated for ADA deficiency with enzyme replacement therapy need regular treatments because the injected enzymes are not a permanent cure. The enzymes only provide temporary relief and break down toxic products in the body for a limited time. They do not fix the underlying genetic defect. For a permanent solution, gene therapy can be considered. This involves introducing a healthy gene for ADA into the patient's bone marrow cells at an early embryonic stage. Since these cells are immortal and can continuously produce new blood cells, they can permanently make the missing ADA enzyme, curing the disease.
In simple words: Enzyme therapy for ADA deficiency is temporary because it only adds enzymes, it does not fix the broken gene. A permanent fix is gene therapy, where a healthy gene is put into early cells, so the body makes its own working enzymes forever.

🎯 Exam Tip: Contrast the temporary nature of enzyme replacement (external enzyme supply) with the permanent potential of gene therapy (correcting the genetic defect in self-renewing cells).

 

Question 3. Saccharomyces cerevisiae, acts as a best host than Encherichia coli for the production of recombinant interferons. Yes or No? Support your answer.
Answer: Yes, `\( Saccharomyces\ cerevisiae \)` (yeast) is a better host than `\( Escherichia\ coli \)` for producing recombinant interferons. This is because yeast cells have the necessary cellular machinery for glycosylation of proteins. Glycosylation is a process where sugar molecules are added to proteins, which is often crucial for the proper function and stability of complex proteins like interferons. `\( E.\ coli \)` bacteria do not have this machinery, so interferons produced in `\( E.\ coli \)` might not be fully functional or stable. Hence, yeast is preferred for such productions.
In simple words: Yes, yeast is better than `\( E.\ coli \)` for making interferons. This is because yeast can add sugar parts to proteins, which makes interferons work better, but `\( E.\ coli \)` cannot.

🎯 Exam Tip: Remember that `\( Saccharomyces\ cerevisiae \)` (yeast) is a eukaryote with post-translational modification capabilities like glycosylation, which prokaryotes like `\( E.\ coli \)` lack, making yeast suitable for complex protein production.

 

Question 4. Isolation of blood to treat Haemophilia A is practically impossible. Give reason.
Answer: Isolating blood for treating Haemophilia A is practically impossible for two main reasons. Firstly, a very large quantity of blood would be needed to get enough Factor VIII, the clotting protein missing in Haemophilia A patients, for effective treatment. Collecting such large amounts of blood repeatedly is not feasible. Secondly, there is a significant risk of transmitting blood-related diseases, like AIDS or hepatitis, if blood from many donors is used. Because of these challenges, it is more practical and safer to use recombinant Factor VIII produced through biotechnology.
In simple words: It is too hard to get enough blood to treat Haemophilia A, and there is a high risk of passing on other diseases through the blood. So, it is not a practical solution.

🎯 Exam Tip: Focus on the two practical limitations: the sheer quantity of blood required and the safety concerns regarding disease transmission.

 

Question 5. Functional Insulin differs from its pre-hormonal form. How?
Answer: Functional insulin is different from its pre-hormonal form, called pro-insulin. Pro-insulin has three parts: A and B chains, which are linked by a C-chain, and it also has a leader sequence at the beginning. To become functional insulin, the leader sequence is removed first. After that, the C-chain is cut out, leaving only the A and B polypeptide chains. These A and B chains are then connected by disulfide bonds, forming the active insulin molecule ready to regulate blood sugar. This maturation process is essential for insulin's biological activity.
In simple words: Pro-insulin has an extra C-chain and a leader sequence. Functional insulin is made after these extra parts are cut off, leaving only the A and B chains linked together.

🎯 Exam Tip: Remember the structural difference: pro-insulin has a C-chain and a leader sequence, both of which are removed to yield mature, functional insulin (A and B chains). This post-translational modification is critical.

 

Question 6. Whether PCR can be done for RNA molecules? Explain.
Answer: Yes, PCR can indeed be performed on RNA molecules, but it requires an extra step. This adapted technique is known as reverse transcription PCR (RT-PCR). In this process, the RNA molecules (specifically messenger RNA or mRNA) are first converted into complementary DNA (cDNA) using an enzyme called reverse transcriptase. Once the cDNA is created, it then serves as the template for the regular PCR amplification, allowing scientists to make many copies of the original RNA sequence. This is a common method for studying gene expression and detecting RNA viruses.
In simple words: Yes, PCR can work for RNA. First, the RNA is changed into DNA using a special enzyme. After that, the DNA is copied many times using the normal PCR steps.

🎯 Exam Tip: Clearly state RT-PCR as the method for RNA, and highlight reverse transcriptase as the key enzyme for the initial RNA-to-cDNA conversion.

 

Question 7. Suggest any two techniques for early diagnosis of bacterial/viral human diseases.
Answer: Two effective techniques for the early diagnosis of bacterial or viral human diseases are PCR (Polymerase Chain Reaction) and ELISA (Enzyme-Linked ImmunoSorbent Assay). PCR can detect the genetic material (DNA or RNA) of pathogens very quickly and precisely, even from tiny samples. ELISA, on the other hand, detects specific antibodies produced by the body in response to an infection, or it can detect the antigens (parts of the pathogen) themselves, also offering high sensitivity for early diagnosis.
In simple words: PCR and ELISA are two good ways to find bacterial or viral diseases early. PCR looks for the germ's genetic code, while ELISA looks for the germ itself or what our body makes to fight it.

🎯 Exam Tip: For each technique, briefly mention what it detects (PCR: genetic material; ELISA: antibodies/antigens) to highlight why it's suitable for early diagnosis.