shaalaa.com
S

Question Paper - Biology 2014 - 2015-CBSE 12th-Class 12 CBSE (Central Board of Secondary Education)

Account
User


Login
Register


      Forgot password?
Share
Notifications

View all notifications
Books Shortlist
Your shortlist is empty
SubjectBiology
Year2014 - 2015 (March)

Alternate Sets

      
 Topics
 Marks
 Topics
 Marks

Marks: 70
Q: 1[1]

How many chromosomes do drones of honey bees possess? Name the type of cell division involved in the production of sperms by them.

view question and solution
Q: 2[1]

What is a cistron?

view question and solution
Q: 3[1]

Retroviruses have no DNA. However, the DNA of the infected host cell does possess viral DNA. How is it possible?

view question and solution
Q: 4[1]

Why do children cured by enzyme-replacement therapy adenosine deaminase deficiency need periodic treatment?

view question and solution
Q: 5[1]

List two advantages of the use of unleaded petrol in automobiles as fuel.

view question and solution
Q: 6[2]

Why do moss plants produce very large number of male gametes? Provide one reason. What are these gametes called?

view question and solution
Q: 7[2]

(a) Select the homologous structures from the combinations given below:

(i) Forelimbs of whales and bats

(ii) Tuber of potato and sweet potato

(iii) Eyes of octopus and mammals

(iv) Thorns of Bougainvillea and tendrils of Cucurbita

 

(b) State the kind of evolution they represent.

view question and solution
Q: 8[2]

(a) Why are the plants raised through micropropagation are termed as somaclones?

(b) Mention two advantages of this technique.

view question and solution
Q: 9[2]

Explain the different steps involved during primary treatment phase of sewage.

view question and solution
Q: 10 | Attempt any one of the following[2]
Q: 10.1[2]

What is mutualism? Mention any two examples where the organisms involved are commercially exploited in agriculture.

view question and solution
Q: 10.2[2]

List any four techniques where the principle of ex-situ conservation of biodiversity has been employed.

view question and solution
Q: 11[2]

State what is apomixis. Comment on its significance. How can it be commercially used?

view question and solution
Q: 12[2]

During a monohybrid cross involving a tall pea plant with a dwarf pea plant, the offspring populations were tall and dwarf in equal ratio. Work out a cross to show how it is possible.

view question and solution
Q: 13[3]

Explain the significance of satellite DNA in DNA fingerprinting technique.

view question and solution
Q: 14[3]

What does the following equation represent? Explain.

p2 + 2pq + q2 = 1

view question and solution
Q: 15[3]

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 question and solution
Q: 16[3]

Enumerate any six essentials of good, effective Dairy Farm Management Practices.

view question and solution
Q: 17 | Attempt any one of the following[3]
Q: 17.1[3]

State the medicinal value and the bioactive molecules produced by Streptococcus, Monascus and Trichoderma.

view question and solution
Q: 17.2[3]

What are methanogens? How do they help to generate biogas?

view question and solution
Q: 18[3]

Rearrange the following in the correct sequence to accomplish an important biological reaction:

(a) In vitro synthesis of copies of DNA of interest

(b) Chemically synthesized oligonucleotides

(c) Enzyme DNA-polymerase

(d) Complementary region of DNA

(e) Genomic DNA template

(f) Nucleotides provided

(g) Primers

(h) Thermostable DNA-polymerase (from Thermus aquaticus)

(i) Denaturation of ds-DNA

view question and solution
Q: 19[3]

Describe any three potential applications of genetically modified plants.

view question and solution
Q: 20[3]

How did an American Company, Eli Lilly use the knowledge of r-DNA technology to produce human insulin?

view question and solution
Q: 21[3]

How do snails, seeds, bears, zooplanktons, fungi and bacteria adapt to conditions unfavourable for their survival?

view question and solution
Q: 22[3]

With the help of a flow chart, show the phenomenon of biomagnifications of DDT in an aquatic food chain.

view question and solution
Q: 23[3]

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 question and solution
Q: 24 | Attempt an one of the following[5]
Q: 24.1[5]

(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

view question and solution
Q: 24.2[5]

Describe the role of pituitary and ovarian hormones during the menstrual cycle in a human female.

view question and solution
Q: 25 | Attempt any one of the following[5]
Q: 25.1[5]

(a) Why are thalassemia and haemophilia categorized as Mendelian disorders? Write the symptoms of these diseases. Explain their pattern of inheritance in humans.

(b) Write the genotypes of the normal parents producing a haemophilic son.

view question and solution
Q: 25.2[5]

How do m-RNA, t-RNA and ribosomes help in the process of translation?

view question and solution
Q: 26 | Attempt any one of the following[5]
Q: 26.1[5]

(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.

view question and solution
Q: 26.2[5]

“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 if examples and sketches.

view question and solution
S