Biotechnology

Step 1: Cloning history.
Clonal transplantation technique का प्रयोग Ian Wilmut ने किया था। उन्होंने प्रसिद्ध भेड़ "Dolly" को clone किया।

Step 2: अन्य विकल्पों का विश्लेषण.
(A) ग्रिफिथ → Transformation experiment किया था।
(B) गुडइन → Plant tissue culture research में कार्य।
(C) हाबर → Nitrogen fixation method (Haber process)।

Step 3: निष्कर्ष.
सही उत्तर है (D) इयान विलमट।

Step 1: Satellite DNA की परिभाषा.
Satellite DNA दोहराए जाने वाले अनुक्रम (repetitive sequences) होते हैं, जो DNA fingerprinting में प्रयोग किए जाते हैं।

Step 2: उपयोग का विश्लेषण.
DNA fingerprinting तकनीक फोरेंसिक विज्ञान में व्यक्ति की पहचान हेतु उपयोगी है।

Step 3: अन्य विकल्पों का विश्लेषण.
(A) जीन निर्धारण → Genes का निर्धारण sequencing से होता है।
(B) अंग प्रत्यारोपण → इसमें compatibility test किया जाता है, Satellite DNA नहीं।
(D) उत्क्रांत अध्ययन → Evolution studies में homologous sequences उपयोगी होते हैं।

Step 4: निष्कर्ष.
सही उत्तर है (C) फोरेंसिक विज्ञान का।

Step 1: Restriction enzymes.
EcoRI, BamHI, HindIII सभी restriction endonucleases हैं, जो DNA को specific sites पर काटते हैं।

Step 2: Pectinase का कार्य.
Pectinase एक enzyme है जो plant cell wall के pectin को तोड़ता है, DNA cut करने का काम नहीं करता।

Step 3: निष्कर्ष.
सही उत्तर है (D) पेक्टिनेज, क्योंकि यह restriction enzyme नहीं है।

Step 1: Antibiotic markers का प्रयोग.
Genetic engineering में antibiotics को selectable marker की तरह इस्तेमाल किया जाता है ताकि recombinant organisms की पहचान की जा सके।

Step 2: अन्य विकल्पों का विश्लेषण.
(A) स्वस्थ संकरण के चयन → यह antibiotics से संबंधित नहीं।
(C) संक्रमण मुक्त रखना → इसके लिए aseptic technique होती है।

Step 3: निष्कर्ष.
सही उत्तर है (B) चयन योग्य चिह्नक के रूप में।

Step 1: परिभाषा.
क्लोनिंग वाहन (Cloning vector) वह DNA अणु है जो विदेशी जीन को वहन करके होस्ट कोशिका में ले जाने और वहाँ प्रतिकृति बनाने के लिए प्रयोग किया जाता है।

Step 2: विशेषताएँ.
- इसमें Ori (Origin of replication) होता है।
- Selectable marker genes होते हैं।
- Restriction sites उपलब्ध होते हैं।

Step 3: उदाहरण.
- Plasmid pBR322
- Bacteriophage vector

Step 4: निष्कर्ष.
क्लोनिंग वाहनों ने आनुवंशिक इंजीनियरिंग और DNA recombinant technology को संभव बनाया।

Step 1: Plant cell capability.
Totipotency refers to the genetic potential of a single cell to develop into an entire organism.
Step 2: Importance in biotechnology.
In plants, this property is used in tissue culture to regenerate full plants from single cells.
Step 3: Conclusion.
Thus, the capacity to generate a whole plant is called Totipotency.

Step 1: Importance of thermostable polymerase.
PCR requires DNA polymerase that can withstand high temperatures of denaturation cycles.
Step 2: Source organism.
Taq polymerase, the thermostable DNA polymerase used in PCR, is isolated from Thermus aquaticus, a thermophilic bacterium living in hot springs.
Step 3: Conclusion.
Thus, thermostable DNA polymerase is obtained from Thermus aquaticus.

Step 1: Understanding cloning vectors.
Cloning vectors are DNA molecules used to carry foreign DNA into host cells for replication and expression.
Step 2: Examples.
- Plasmids and bacteriophages are common bacterial cloning vectors.
- pBR322 is a widely used plasmid vector in bacteria.
- T-DNA, however, is a part of Agrobacterium’s Ti plasmid, used for gene transfer in plants, not bacteria.
Step 3: Conclusion.
Thus, T-DNA is not a cloning vector for bacteria.

Step 1: Methods of DNA introduction.
Different methods are used to introduce recombinant DNA into host cells — transformation, transfection, gene gun, and microinjection.
Step 2: Direct introduction into nucleus.
Microinjection involves directly injecting recombinant DNA into the nucleus of an animal cell using fine needles under a microscope.
Step 3: Conclusion.
Therefore, the correct method is Microinjection.

Step 1: Cell wall composition.
Fungal cell walls are mainly composed of chitin. To break open fungal cells for DNA isolation, the enzyme chitinase is used.
Step 2: Analyzing options.
(A) Lysozyme: Correct for bacteria (acts on peptidoglycan).
(B) Cellulase: Correct for plant cells (acts on cellulose).
(C) DNase: Incorrect — It degrades DNA, not used for extraction.
(D) Chitinase: Correct — Breaks down fungal cell walls.
Step 3: Conclusion.
Thus, Chitinase is used for DNA isolation from fungi.

Step 1: Features of pBR322.
pBR322 is a commonly used cloning vector in bacteria. It contains:
- Origin of replication (ori).
- Restriction sites for cloning.
- Antibiotic resistance genes (ampicillin, tetracycline).
Step 2: Absent component.
T-DNA is specific to Agrobacterium Ti plasmid, used for plant transformation, not bacterial cloning vectors like pBR322.
Step 3: Conclusion.
Hence, T-DNA is absent in pBR322.

Step 1: Double antibiotic resistance marker in pBR322.
pBR322 has resistance genes for both ampicillin and tetracycline. If a foreign gene is inserted into one of these, that resistance is lost.
Step 2: Insertion in tetracycline resistance gene.
If foreign DNA is inserted into the tetracycline resistance gene, the bacteria carrying recombinant plasmid will not be resistant to tetracycline.
Step 3: Conclusion.
Thus, insertion leads to loss of tetracycline resistance.

Step 1: Separation method.
DNA fragments are separated by a technique called gel electrophoresis. Agarose gel acts as a medium.
Step 2: Principle.
DNA is negatively charged (due to phosphate groups). When an electric field is applied, DNA fragments move towards the positive electrode. Smaller fragments move faster than larger ones.
Step 3: Visualization.
DNA fragments are stained with ethidium bromide or other dyes and visualized under UV light.
Step 4: Isolation.
The specific DNA fragment is cut out from the gel and extracted for further use.
Step 5: Conclusion.
Gel electrophoresis allows both separation and isolation of DNA fragments.

Step 1: Understanding PCR (Polymerase Chain Reaction).
Polymerase Chain Reaction (PCR) is a laboratory technique used to amplify specific segments of DNA. It enables researchers to create millions of copies of a gene of interest from a small amount of DNA. The process involves several key steps:
1. Denaturation: The double-stranded DNA is heated to 94-98°C, causing the DNA to separate into two single strands.
2. Annealing: The temperature is lowered to 50-65°C, allowing the primers (short single-stranded sequences) to bind to the target DNA sequences at the beginning and end of the gene of interest.
3. Extension: The temperature is raised to 75-80°C, and DNA polymerase synthesizes new DNA strands starting from the primers, copying the gene of interest. This process is repeated multiple times to generate millions of copies.
Step 2: Conclusion.
PCR amplifies a gene of interest by repeatedly denaturing, annealing, and extending DNA, resulting in the production of large quantities of the target gene.

Step 1: Basis of naming.
Restriction endonucleases are named according to the bacterium from which they are isolated.
Step 2: Rules.
1. The first letter → genus (capital).
2. Next two letters → species (small letters).
3. Strain of bacterium may be mentioned.
4. Roman numeral indicates the order of discovery.
Step 3: Example.
EcoRI:
- E → Escherichia (genus)
- co → coli (species)
- R → strain RY13
- I → First enzyme isolated from this strain.
Step 4: Conclusion.
Thus, restriction enzymes are named scientifically using genus, species, strain, and discovery order.

Step 1: Understanding amplification of nucleic acid.
Amplification means producing multiple copies of a specific DNA sequence. The most widely used method for this is Polymerase Chain Reaction (PCR).
Step 2: Analyzing the options.
(A) Transformation: Incorrect — It introduces foreign DNA into a host, not amplification.
(B) Transfection: Incorrect — This refers to introducing nucleic acids into eukaryotic cells, not amplification.
(C) PCR: Correct — PCR is the standard technique for amplifying DNA in vitro, producing millions of copies.
(D) Micropropagation: Incorrect — It is a plant tissue culture technique, unrelated to nucleic acid amplification.
Step 3: Conclusion.
The correct method for amplification of nucleic acid is PCR.

Step 1: Property of DNA.
DNA molecules carry a negative charge due to the phosphate groups in their sugar-phosphate backbone.
Step 2: Principle of electrophoresis.
In gel electrophoresis, negatively charged DNA fragments migrate towards the positive electrode (anode) when an electric current is applied.
Step 3: Conclusion.
Therefore, DNA moves towards the anode because it is negatively charged.

Microorganisms are essential in various fields of research due to their diverse applications. Step 1: Role in scientific research.
Microorganisms serve as model organisms in biological research. Their rapid reproduction and genetic similarity to higher organisms make them ideal for studying genetics, evolution, and disease mechanisms.
Step 2: Industrial and medical importance.
- Medical research. Microorganisms like bacteria and fungi help in the development of antibiotics and vaccines. - Biotechnology. They are used in the production of enzymes, biofuels, and fermented foods.
Final Answer: Microorganisms are important in research for studying genetics, disease, and industrial applications like antibiotics and biotechnology.

Recombinant technology involves the manipulation of an organism's genetic material to introduce new genes, enabling the production of desired proteins or traits. Below is a simple diagram illustrating the process of recombinant DNA technology.

Step 1: Key Steps in Recombinant DNA Technology.
1. Gene Isolation: The desired gene is isolated from the organism's DNA using restriction enzymes. 2. Gene Insertion: The isolated gene is inserted into a vector (often a plasmid) using ligase enzymes. 3. Transformation: The recombinant DNA is introduced into a host organism (often bacteria) for replication. 4. Selection: The transformed cells are selected, usually using an antibiotic resistance marker. 5. Expression: The host organism expresses the inserted gene, producing the desired protein.
Final Answer: The diagram above illustrates the key steps in recombinant DNA technology, including gene isolation, insertion into a vector, transformation, selection, and protein expression.

A gene library, also known as a DNA library, is a collection of DNA fragments that represent the genetic material of an organism. Step 1: Understanding gene libraries.
- Gene libraries store genetic information in a variety of forms, including cDNA or genomic DNA, often stored in vectors like plasmids.
Step 2: Importance of gene libraries.
- Gene libraries are used in molecular biology to isolate specific genes for further study or manipulation.
Final Answer: A gene library is a collection of DNA fragments used for studying genes and their functions.

Genetically modified (GM) animals have been engineered to express desired traits, which can be beneficial in various fields. Step 1: Improved resistance to diseases.
GM animals can be engineered to have enhanced immunity, helping them resist diseases that would otherwise reduce their population or harm their utility.
Step 2: Better productivity.
GM animals can be modified for traits such as faster growth, improved reproduction rates, or better quality products (e.g., milk, meat), which helps increase agricultural efficiency.
Final Answer: 1. Improved resistance to diseases. 2. Better productivity in agriculture.

Step 1: Understand Cry-toxin.
Cry-toxin is a protein toxin produced by the bacterium Bacillus thuringiensis. It is used in pest control, especially in crops. The toxin can cause multiple effects on the target organism.
Step 2: Review the options.
- Cry-toxin can cause swelling of cells, binding to the epithelium of the midgut, and also the lysis (destruction) of intestinal cells. Hence, more than one of these options is correct. - Options (A), (B), and (C) describe the effects of Cry-toxin, which all lead to the disruption of the digestive system in insects.
Step 3: Conclude.
Since Cry-toxin can cause all of the listed effects, option (D) is the correct answer.
Final Answer:

Step 1: Understand mutation induction.
Gamma rays are high-energy electromagnetic radiation used in plant breeding to induce mutations for improving crops.
Step 2: Review the options.
- Gamma rays are the most common radiation used to induce mutations in crop plants.
- Alpha rays and X-rays are not typically used in mutation breeding.
- Sunrays do not have enough energy to induce mutations in plant DNA.
Step 3: Conclude.
Gamma rays are used to induce mutations in crop plants, making option (A) the correct answer.
Final Answer: