Class 12th Biology 2012 Set1 Delhi Board Paper Solution
Question 12
(a) State the role of DNA ligase in biotechnology.
(a) State the role of DNA ligase in biotechnology.
(b) What happens when Meloidegyne incognitia consumes cells with RNAi gene?
Answer
(a) DNA ligase enzyme is used to join two DNA fragments from their ends.
(b) When Meloidogyne incognita (parasite) consumes cells with RNAi gene, parasite cannot survive and this prevents infestation. The introduced RNAi gene DNA forms both sense and anti-sense RNA. Two strands being complementary to each other bend and form ds RNA, leading to RNAi. Thus, the mRNA of nematode is silenced and the parasite cannot survive there.
Popular Questions of Class 12th biology
- Q:- What is spermatogenesis? Briefly describe the process of spermatogenesis.
- Q:- Why is reproduction essential for organisms? Answer
- Q:- Write a short note on
(a) Adaptations of desert plants and animals
(b) Adaptations of plants to water scarcity
(c) Behavioural adaptations in animals
(d) Importance of light to plants
(e) Effect of temperature or water scarcity and the adaptations of animals. - Q:- With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte.
- Q:- What is DNA fingerprinting? Mention its application.
- Q:- What is oogenesis? Give a brief account of oogenesis.
- Q:- Describe the structure of a seminiferous tubule.
- Q:- What is triple fusion? Where and how does it take place? Name the nuclei involved in triple fusion.
- Q:- With a neat, labelled diagram, describe the parts of a typical angiosperm ovule.
- Q:- Explain the Law of Dominance using a monohybrid cross.
Recently Viewed Questions of Class 12th biology
- Q:- In our society the women are often blamed for giving birth to daughters.
Can you explain why this is not correct? - Q:- Why do you think the zygote is dormant for sometime in a fertilized ovule?
- Q:- With a neat, labelled diagram, describe the parts of a typical angiosperm ovule.
- Q:- Which one of the following has the largest population in a food chain?
(a) Producers
(b) Primary consumers
(c) Secondary consumers
(d) Decomposers - Q:- Do you think that reproductive health in our country has improved in the past 50 years? If yes, mention some such areas of improvement.
- Q:- What are the major functions of male accessory ducts and glands?
- Q:- Most living organisms cannot survive at temperature above 45°C°. How are some microbes able to live in habitats with temperatures exceeding 100°C?
- Q:- Higher organisms have resorted to sexual reproduction in spite of its complexity. Why?
- Q:- Correct the following statements:
(a) Surgical methods of contraception prevent gamete formation.
(b) All sexually transmitted diseases are completely curable.
(c) Oral pills are very popular contraceptives among the rural women.
(d) In E. T. techniques, embryos are always transferred into the uterus. - Q:-
What is menstrual cycle? Which hormones regulate menstrual cycle?