Biotechnology and Its Applications
- Choose the correct pair from the following : Answer: 1. Ligases - Join the two DNA molecules Key idea: Ligases join DNA fragments. DNA ligase seals the sugar-phosphate backbone between... 1
- Which of the following is true for Golden rice ? Answer: 1. It is Vitamin A enriched, with a gene from daffodil. Key idea: Golden rice is a biofortified rice rich in provitamin A (beta-caro... 1
- What triggers activation of protoxin to active Bt toxin of Bacillus thuringiensis in boll worm ? Answer: 3. Alkaline pH of gut Key idea: The Bt protoxin is activated by alkaline pH. Bt toxin crystals exist as inactive protoxin. In the al... 1
- DNA precipitation out of a mixture of biomolecules can be achieved by treatment with : Answer: 2. Chilled ethanol DNA is precipitated by adding chilled ethanol, and it then appears as fine threads that can be spooled out. Optio... 1
- Following statements describe the characteristics of the enzyme Restriction Endonuclease. Identify the incorrect statement. Answer: 2. The enzyme binds DNA at specific sites and cuts only one of the two strands. Key idea: Restriction endonucleases cut both strands... 1
- Which one of the following equipments is essentially required for growing microbes on a large scale, for industrial production of enzymes ? Answer: 4. Bioreactor Large-scale culture of microbes for products such as enzymes needs a bioreactor, which gives controlled temperature, p... 1
- In India, the organisation responsible for assessing the safety of introducing genetically modified organisms for public use is Answer: 4. Genetic Engineering Appraisal Committee (GEAC) In India GEAC (Genetic Engineering Appraisal Committee) decides on the safety of G... 1
- Use of bioresources by multinational companies and organisations without authorisation from the concerned country and its people is called Answer: 3. Biopiracy Using biological resources or related knowledge without proper authorisation and payment is called biopiracy. Biodegrad... 1
- A ‘new’ variety of rice was patented by a foreign company, though such varieties have been present in India for a long time. This is related to Answer: 4. Basmati A foreign company patented Basmati rice (a US patent to RiceTec), though India has grown basmati for centuries. Co-667 is... 1
- The correct order of steps in Polymerase Chain Reaction (PCR) is Answer: 4. Denaturation, Annealing, Extension PCR is a cycle of three steps in a fixed order: denaturation, annealing, extension. Heat (abou... 1
- Which of the following is commonly used as a vector for introducing a DNA fragment in human lymphocytes ? Answer: 1. Retrovirus To put a gene into animal cells such as human lymphocytes, disarmed retroviruses are used as vectors. Retroviruses inf... 1
- A gene whose expression helps to identify transformed cell is known as : Answer: 4. Selectable marker A selectable marker is a gene whose expression lets us identify and select transformed cells, for example an an... 1
- What is the criterion for DNA fragments movement on agarose gel during gel electrophoresis ? Answer: 1. The smaller the fragment size, the farther it moves Key idea: The gel acts as a sieve. All DNA fragments are negatively charged a... 1
- DNA fragments are : Answer: 1. Negatively charged Key idea: DNA has a phosphate group on each nucleotide. The phosphate groups carry a negative charge, so every... 1
- The process of separation and purification of expressed protein before marketing is called : Answer: 1. Downstream processing Key idea: Making a product has two stages. Upstream processing covers growing the cells in a bioreactor. Do... 1
- The DNA fragments separated on an agarose gel can be visualised after staining with : Answer: 3. Ethidium bromide Key idea: DNA bands on agarose are seen with a dye that binds DNA and fluoresces. Ethidium bromide intercalates... 1
- Which kind of therapy was given in 1990 to a four-year-old girl with adenosine deaminase (ADA) deficiency? Answer: 4. Gene therapy In 1990 a four-year-old girl with ADA deficiency received the first clinical gene therapy: lymphocytes were taken, a... 1
- Stirred-tank bioreactors have been designed for Answer: 2. availability of oxygen throughout the process A stirred-tank bioreactor has an agitator and a sparger. Stirring mixes the content... 1
- A foreign DNA and plasmid cut by the same restriction endonuclease can be joined to form a recombinant plasmid using Answer: 3. ligase The same restriction enzyme gives matching sticky ends on the foreign DNA and plasmid. These ends anneal, and DNA ligase s... 1
- Which of the following is not a component of downstream processing? Answer: 3. Expression Downstream processing includes separation, purification and preservation of the product after the biosynthesis stage.... 1
- Which of the following restriction enzymes produces blunt ends? Answer: 1. *Eco* RV EcoRV cuts in the middle of its recognition site (GAT^ATC) and gives blunt ends. XhoI, HindIII and SalI cut with a stagg... 1
- Which part of the tobacco plant is infected by *Meloidogyne incognita* ? Answer: 4. Root Key idea: The nematode Meloidogyne incognita infects the roots of tobacco. It causes root-knot galls and reduces yield. In b... 1
- Which of the following is a restriction endonuclease ? Answer: 1. Hind II Hind II is a restriction endonuclease, an enzyme from bacteria that cuts DNA at specific recognition sequences. Protease... 1
- The taq polymerase enzyme is obtained from : Answer: 1. *Thermus aquaticus* Key idea: Taq polymerase comes from the thermophilic bacterium Thermus aquaticus. It is stable at the high te... 1