Questions: Biotechnology and its Applications

Q1. Which part of a plant is best for making virus-free plants, and why?

Answer (English): The growing tip, or meristem, is the part to use. A virus may fill the rest of the plant, yet it does not reach the actively dividing cells of the apical or axillary tip, so the meristem stays virus-free. Growing the meristem in vitro on a sterile nutrient medium therefore gives a virus-free plant.

Hinglish: Sabse achha hissa meristem hai, yaani apical ya axillary growing tip. Poori plant virus se infected hone par bhi meristem virus-free rehta hai kyunki virus tezi se divide hone wale tip cells tak nahi pahunchta. Meristem ko sterile nutrient medium par in vitro ugane se virus-free plant mil jaati hai.

Q2. State the biggest advantage of raising plants through micropropagation.

Answer (English): With micropropagation a small explant yields thousands of plants in a short span, and each one is genetically identical to the parent, which makes them somaclones. That makes it possible to multiply a desirable variety quickly, and the method works even for plants that are hard to propagate by seed in the field.

Hinglish: Micropropagation se chhote explant se bahut kam samay mein hazaaron plants banti hain, aur sab plants parent ke genetically identical hote hain, isliye unhe somaclones kehte hain. Isse achhi variety tezi se multiply hoti hai, aur un plants ke liye bhi kaam karta hai jinhe beejon se badhana mushkil hota hai.

Q3. What components must the medium supply for propagation of an explant in vitro?

Answer (English): The medium has to supply sugar, mineral salts, vitamins, amino acids and growth regulators from the auxin and cytokinin groups. The culture must also be kept sterile, because a microbe that gets in would grow faster than the explant and spoil the culture.

Hinglish: Medium mein sucrose jaise carbon source, inorganic salts, vitamins, amino acids aur auxins aur cytokinins jaise growth regulators hone chahiye. Culture sterile rakhni padti hai, kyunki koi microbe ghus gaya to woh explant se tezi se badhkar culture kharab kar dega.

Q4. Crystals of Bt toxin do not kill the bacteria that make them. Why?

Answer (English): The toxin is stored inside the bacteria in an inactive form called a protoxin, so it cannot act on the bacterial cells. It becomes active only after an insect eats it, when the alkaline pH of the insect gut solubilises the crystal and converts the protoxin into the active toxin.

Hinglish: Toxin bacteria ke andar inactive protoxin ki tarah store hota hai, isliye woh bacterial cells par kaam nahi karta. Woh tab active hota hai jab insect use khaata hai, aur insect ke gut ka alkaline pH crystal ko ghulakar protoxin ko active toxin bana deta hai.

Q5. What are Cry proteins? Name the organism that produces them and explain how humans have used them.

Answer (English): Cry proteins are insecticidal proteins produced by the bacterium Bacillus thuringiensis. Some strains of the bacterium make crystals of these proteins during a particular growth phase, and the proteins are specific to insect groups such as lepidopterans, coleopterans and dipterans. Scientists have cloned the cry genes and expressed them in crops, so the plant itself makes the toxin and becomes resistant to the target insect. Bt cotton, Bt corn and Bt rice are examples.

Hinglish: Cry proteins Bacillus thuringiensis naam ke bacterium ke insecticidal proteins hain. Bacterium kisi growth phase mein inke crystals banata hai, aur ye proteins lepidopterans, coleopterans aur dipterans jaise insect groups ke liye specific hote hain. Scientists ne cry genes clone karke crops mein express kiye, isliye plant khud toxin banata hai aur target insect ke liye resistant ho jaata hai. Bt cotton, Bt corn aur Bt rice iske example hain.

Q6. What are transgenic bacteria? Give one example.

Answer (English): A transgenic bacterium is a bacterium whose DNA has been deliberately altered to carry an extra gene, usually so that it produces a useful protein. The classic example is Escherichia coli carrying human insulin genes. Two DNA sequences, for the A and B chains, were put into E. coli, the chains were produced separately, and they were then joined by disulphide bonds to form human insulin.

Hinglish: Transgenic bacterium woh bacterium hai jiski DNA mein jaan-boojhkar extra gene daala gaya ho, aksar isliye ki woh koi useful protein banaye. Classic example E. coli hai jismein human insulin ke genes daale gaye. A aur B chains ke liye do DNA sequences E. coli mein daali gayi, chains alag-alag bani, aur phir disulphide bonds se jodkar human insulin banaya gaya.

Q7. Can insulin be given by mouth? Explain.

Answer (English): No, insulin cannot be given by mouth in its normal form. Insulin is a protein, and the digestive enzymes of the gut would break it down before it reached the blood, so it would lose its activity. This is why insulin is injected, and why making an orally active protein medicine is a difficult problem.

Hinglish: Insulin ko normal form mein muh se nahi diya ja sakta. Insulin ek protein hai, aur gut ke digestive enzymes use khoon tak pahunchne se pehle tod denge, isliye uski activity khatam ho jayegi. Isi wajah se insulin injection se diya jaata hai, aur orally active protein dawa banana mushkil kaam hai.

Q8. What is gene therapy? Illustrate with adenosine deaminase deficiency.

Answer (English): Gene therapy is a set of methods that corrects a gene defect already diagnosed in a child or embryo by delivering a normal gene into the person's cells, so the normal gene takes over the work of the faulty one. In ADA deficiency, a four-year-old girl received the first clinical gene therapy in 1990. Lymphocytes taken from her blood were grown in culture, a functional ADA cDNA was put into them with a retroviral vector, and the cells were returned to her. Because lymphocytes are not immortal, she needed periodic infusions of engineered cells.

Hinglish: Gene therapy mein pehle se diagnose hue gene defect ko theek karne ke liye normal gene cells mein daala jaata hai, taki normal gene faulty gene ka kaam le le. ADA deficiency mein 1990 mein pehli clinical gene therapy ek 4 saal ki bachchi ko di gayi. Uske khoon ke lymphocytes culture mein badhaye gaye, retroviral vector se ADA cDNA daala gaya, aur cells wapas diye gaye. Lymphocytes immortal nahi hote, isliye usse baar baar engineered cells ka infusion chahiye tha.

Q9. Name the techniques used for early diagnosis of a disease and explain one of them.

Answer (English): Recombinant DNA technology, PCR, ELISA and the probe method are used for early diagnosis. PCR is the clearest example. An infection is normally suspected only after symptoms appear, when the pathogen is already numerous. PCR amplifies the pathogen's nucleic acid, so even a very small number of bacteria or viruses present before symptoms can be detected. PCR helps detect HIV in people suspected of AIDS and gene mutations in people suspected of cancer. The probe method uses a single stranded DNA or RNA carrying a radioactive tag, which pairs with a complementary sequence; autoradiography then reveals the spot; a mutated clone does not appear because the probe cannot pair with it. ELISA detects the pathogen through antigens or through the antibodies made against it.

Hinglish: Early diagnosis ke liye recombinant DNA technology, PCR, ELISA aur probe method use hote hain. PCR sabse saaf example hai: infection ke symptoms dikhne se pehle pathogen ki matra bahut kam hoti hai, lekin PCR uske nucleic acid ko amplify kar deta hai, isliye thode se bacteria ya virus bhi pakde jaate hain. PCR se HIV aur cancer ke gene mutations detect hote hain. Probe method mein radioactive tag wala single stranded DNA ya RNA complementary sequence se pair karta hai aur autoradiography se spot dikhta hai; mutated clone film par nahi aata. ELISA pathogen ke antigens ya uske against bane antibodies se infection pakadta hai.

Q10. What is biopiracy? Give an example from India.

Answer (English): Biopiracy happens when companies and other organisations take bio-resources without the permission of the country and the people who own them, and without paying for them. The Basmati rice case is an Indian example. In 1997 an American company obtained patent rights on Basmati through the US Patent and Trademark Office. The claimed variety had actually been derived from Indian farmers' varieties, yet the patent allowed the company to sell a new Basmati in the US and abroad and to restrict other sellers through functional equivalents. Attempts to patent uses of turmeric and neem are similar examples.

Hinglish: Biopiracy tab hoti hai jab multinational companies aur doosri organisations bio-resources ka istemaal bina sambandhit desh aur logon ki authorisation ke, aur bina compensatory payment ke karti hain. Basmati rice ka case Indian example hai: 1997 mein ek American company ko US Patent and Trademark Office se Basmati par patent rights mil gaye. Claimed variety asal mein Indian farmers ki varieties se nikli thi, phir bhi patent se company naye Basmati ko bech sakti thi aur doosre bechne walon ko rok sakti thi. Turmeric aur neem ke use par patent ki koshish bhi aisa hi example hai.

To check how much of this stuck, take the five-question quiz below. Each answer explains the reasoning, so read the explanation even when you get it right.

Quiz: the five question check for this chapter is set from the same topics. Attempt it after the questions above, then revisit any topic page where you lost a mark.