Suggest and describe a technique to obtain multiple copies of a gene of interest in vitro.
The technique to obtain multiple copies of a gene is PCR - Polymerase Chain rection.
It invoves the following steps.
Denaturing – The double-stranded template DNA is heated to separate it into two single strands.
Annealing – The temperature is lowered to enable the DNA primers to attach to the template DNA.
Extending – The temperature is raised and the new strand of DNA is made by the Taq polymerase enzyme.
These three stages are repeated 20-40 times, doubling the number of DNA copies each time.
Identify'A' , 'B', 'C' and 'D' in the given table
| Crop | Variety | Resistance to disease |
| A | Himgiri | Leaf rust |
| Cauliflower | Pusa Shubhra | B |
| Brassica | Pusa Swarnim | C |
| Cowpea | D | Bacterial blight |
Why is breast-feeding recommended during the initial period od an infant's growth? Give reasons.
Give an example of an autosomal recessive trait in humans. Explain its pattern of inheritance with the help of a cross.
During a school trip to 'Rohtang pass' one of your classmate suddenly developed 'Altitude sickness'. But, she recovered after sometime.
(a) Mention one symptom to diagnose the sickness.
(b) What causes the sickness?
(c) How could she recover by herself after sometime?
How has RNAi technique helped to prevent the infestation of roots in tobacco plants by a nematode Meloidegyne incognita?
In in a food-chain, a trophic level represents a functional level, not a species. Explain.
