Class 12th Biology 2016 Set2 Delhi Board Paper Solution

Section 1

Q1	Suggest a technique to a researcher who needs to separate Fragments of DNA.
Q2	State a difference between gene and an allelle.
Q3	Give an example of a human disorder that is caused due to a single gene mutation.
Q4	Suggest the breeding method most suitable for animals that are below average in milk productivity.
Q5	Excessive nutrients in a fresh water body cause fish mortality. Give two reasons.

Section 2

Q6	Name the caustive organism of the disease amoebiasis. List three symtoms of the disease. Or Identify A B C and D in the given table.
Q7	Discuss the role of enzyme DNA ligase plays during DNA replication.
Q8	Explain the importance of syngamy and meiosis in a sexual life cycle of an organism.
Q9	List the events that lead to biogas production from waste water whose BOD has been reduced significantly.
Q10	Why the plants that inhabit a desert are not found in a mangrove ? Give reasons.

Section 3

Q11	Describe the experiment that helped Louis Pasteur to dismiss the theory of spontaneous generation of life.
Q12	Differentiate between somaclones and somatic hybrids. Give one example of each.
Q13	Why is breast-feeding is recommended during the initial period of infant's growth? Give reasons.
Q14	Suggest and describe a technique to obtain multiple copies of a gene of interest in vitro.
Q15	What is a GMO ? List any five possible advantages of GMO to a farmer.
Q16	Given below is a list of six micro-organisms. State their usefulness to humans. Nucleopolyhedrovirus Saccharomyces cerevisiae Monascus purpureus Trichoderma polysporum Penicillium notatum Propionibacterium sharnanii
Q17	A couple with normal vision bear a colour blind child. Work out a cross to show how it is possible and mention the sex of the affected child.
Q18	Prior to a sports event blood and urine samples of sportspersons are collected for drug tests. (a) Why there is a need to conduct such tests ? (b) Name the drugs the authorities usually look for. (c) Write the generic name of two plants from which these drugs are obtained.
Q19	In certain seasons we sweat profusely while in some other season we shiver. Explain.
Q20	“In a food-chain, a trophic level represents a functional level, not a species.” Explain. OR (a) Name any two places where it is essential to install electrostatic precipitators. Why it is required to do so ? (b) Mention one limitation of the electrostatic precipitator.
Q21	How has RNAi technique helped to prevent the infestation of roots in tobacco plants by a nematode ?
Q22	Give an example of an autosomal recessive trait in humans. Explain its pattern of inheritance with the help of a cross.

Section 4

Q23	Reproductive and Child Healthcare (RCH) programmes are currently in operation. One of the major tasks of these programmes is to create awareness amongst people about the wide range of reproduction related aspects. As this is important and essential for building a reproductively healthy society. (a) “Providing sex education in schools is one of the ways to meet this goal.” Give four points in support of your opinion regarding this statement. (b) List any two ‘indicators’ that indicate a reproductively healthy society.
Q24	(a) Why should we conserve biodiversity ? How can we do it ? (b) Explain the importance of biodiversity hot-spots and sacred groves. OR (a) Represent diagrammatically three kinds of age pyramids for human populations. (b) How does an age pyramid for human population at given point of time helps the policy-makers in planning for future.
Q25	(a) Explain the post-pollination events leading to seed production in angiospersms. (b) List the different types of pollination depending upon the source of pollen grain. OR (a) Briefly explain the events of fertilization and implantation in an adult human female. (b) Comment on the role of placenta as an endocrine gland.
Q26	List the criteria a molecule that can act as genetic material must fulfill. Which one of the criteria are best fulfilled by DNA or by RNA thus making one of them a better genetic material than the other ? Explain.
Q26	(a) Differentiate between analogy and homology giving one example each of plant and animal respectively. (b) How are they considered as an evidence in support of evolution ?