Board Paper of Class 12-Science 2015 Biology (SET 2) - Solutions
(i) There are a total of 26 questions and five sections in the question paper, All questions are compulsory.
(ii) Section A contains question number 1 to 5, Very Short Answer type questions of one mark each.
(iii) Section B contains question number 6 to 10, Short Answer type I questions of two marks each.
(iv) Section C contains question number 11 to 22, Short Answer type II questions of three marks each.
(v) Section D contains question number 23, Value Based Question of four marks.
(vi) Section E contains question number 24 to 26, Long Answer type questions of five marks each.
(vii) There is no overall choice in the question paper, however, an internal choice is provided in one question of two marks, one question of three marks and all three questions of five marks. An examinee is to attempt any one of the questions out of the two given in the question paper with the same question number.
- Question 1
List two advantages of the use of unleaded petrol in automobiles as fuel. VIEW SOLUTION
- Question 2
Retroviruses have no DNA. However, the DNA of the infected host cell does possess viral DNA. How is it possible? VIEW SOLUTION
- Question 3
State the cause of adenosine deaminase enzyme deficiency. VIEW SOLUTION
- Question 4
What is a cistron? VIEW SOLUTION
- Question 5
How many chromosomes do drones of honeybee possess? Name the type of cell division involved in the production of sperms by them. VIEW SOLUTION
- Question 6
What is mutualism? Mention any two examples where the organisms involved are commercially exploited in agriculture.
List any four techniques where the principle of ex-situ conservation of biodiversity has been employed. VIEW SOLUTION
- Question 7
(a) Why are the plants raised through micropropagation termed as somaclones ?
(b) Mention two advantages of this technique. VIEW SOLUTION
- Question 8
Explain the process of secondary treatment given to the primary effluent up to the point it shows significant change in the level of biological oxygen demand (BOD) in it. VIEW SOLUTION
- Question 9
(a) Select the analogous structures from the combinations given below :
(i) Forelimbs of whales and bats
(ii) Eyes of octopus and mammals
(iii) Tuber of sweet potato and potato
(iv) Thorns of Bougainvillea and tendrils of Cucurbita
(b) State the kind of evolution they represent.VIEW SOLUTION
- Question 10
A moss plant is unable to complete its life-cycle in a dry environment. State two reasons. VIEW SOLUTION
- Question 11
A heavily bleeding and bruised road accident victim was brought to a nursing home. The doctor immediately gave him an injection to protect him against a deadly disease.
(a) Write what did the doctor inject into the patient's body.
(b) How do you think this injection would protect the patient against the disease?
(c) Name the disease against which this injection was given and the kind of immunity it provides. VIEW SOLUTION
- Question 12
Explain the significance of satellite DNA in DNA fingerprinting technique. VIEW SOLUTION
- Question 13
What does the following equation represent? Explain
p2 + 2 pq + q2 = 1 VIEW SOLUTION
- Question 14
Two independent monohybrid crosses were carried out involving a tall pea plant with a dwarf pea plant. In the first cross, the offspring population had equal number of tall and dwarf plants, whereas in the second cross it was different. Work out the crosses, and explain giving reasons for the difference in the offspring populations. VIEW SOLUTION
- Question 15
State what is apomixis. Comment on its significance. How can it be commercially used? VIEW SOLUTION
- Question 16
State the medicinal value and the bioactive molecules produced by Streptococcus, Monascus and Trichoderma.
What are methanogens ? How do they help to generate biogas ? VIEW SOLUTION
- Question 17
Describe any three potential applications of genetically modified plants. VIEW SOLUTION
- Question 18
How did an American Company. Eli Lilly use the knowledge of r-DNA technology to produce human insulin? VIEW SOLUTION
- Question 19
Explain co-evolution with reference to parasites and their hosts. Mention any four special adaptive features evolved in parasites for their parasitic mode of life. VIEW SOLUTION
- Question 20
Rearrange the following in the current sequences to accomplish an important biotechnological reaction :
(a) In vitro synthesis of region of DNA of interest
(b) Chemically synthesised oligonucleotides
(c) Enzyme DNA-polymerase
(d) Complementary region of DNA
(e) Genomic DNA template
(f) Nucleotides provided
(h) Thermostable DNA-polymerase (from Thermus aquaticus)
(i) Denaturation of ds-DNA VIEW SOLUTION
- Question 21
With the help of a flow-chart exhibit the events of eutrophication. VIEW SOLUTION
- Question 22
Enumerate any six essentials of good, effective Dairy Farm Management Practices. VIEW SOLUTION
- Question 23
Your school has been selected by the Department of Education to organize and host an interschool seminar on "Reproductive Health – Problems and Practices". However, many parents are reluctant to permit their wards to attend it. Their argument is that the topic is "too embarrassing."
Put forth four arguments with appropriate reasons and explanation to justify the topic to be very essential and timely. VIEW SOLUTION
- Question 24
(a) List the different attributes that a population has and not an individual organism.
(b) What is population density ? Explain any three different ways the population density can be measured, with the help of an example each.OR"It is often said that the pyramid of energy is always upright. On the other hand, the pyramid of biomass can be both upright and inverted." Explain with the help of examples and sketches. VIEW SOLUTION
- Question 25
(a) Plan an experiment and prepare a flow chart of the steps that you would follow to ensure that the seeds are formed only from the desired sets of pollen grains. Name the type of experiment that you carried out.
(b) Write the importance of such experiments.OR
Describe the roles of pituitary and ovarian hormones during the menstrual cycle in a human female. VIEW SOLUTION
- Question 26
(a) Why are colour blindness and thalassemia categorised as Mendelian disorders ? Write the symptoms of these diseases seen in people suffering from them.
(b) About 8% of human male population suffers from colour blindness whereas only about 0.4% of human female population suffers from this disease. Write an explanation to show how it is possible.ORExplain the process of transcription in prokaryotes. How is the process different in eukaryotes ? VIEW SOLUTION