Board Paper of Class 12-Science 2017 Biology (SET 1) - Solutions

General Instructions :
(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
Our government has intentionally imposed strict conditions for M.T.P. in our country. Justify giving a reason. VIEW SOLUTION

Question 2
State the fate of a pair of autosomes during gamete formation. VIEW SOLUTION

Question 3
What role does an individual organism play as per Darwin's theory of natural selection? VIEW SOLUTION

Question 4
Suggest a method to ensure an anamnestic response in humans. VIEW SOLUTION

Question 5
What is biopiracy? VIEW SOLUTION

Question 6
A mature embryo-sac in a flowering plant may possess 7-cells, but 8-nuclei. Explain with the help of diagram only. VIEW SOLUTION

Question 7
Describe the structure of a nucleosome.

OR

Mention the evolutionary significance of the following organisms :

(a) Shrews

(b) Lobefins

(c) Homo habilis

(d) Homo erectus VIEW SOLUTION

Question 8
In an agricultural field there is a prevalence of the following organisms and crop diseases which are affecting the crop yield badly:
(a) White rust
(b) Leaf and stripe rust
(c) Black rot
(d) Jussids

Recommend the varieties of crops the farmers should grow to get rid of the existing problem and thus improve the crop yield. VIEW SOLUTION

Question 9
How does the application of the fungal genus, Glomus, to the agricultural farm increase the farm output? VIEW SOLUTION

Question 10
Plenty of algal bloom is observed in a pond in your locality.

(a) Write what has caused this bloom and how does it affect the quality of water.
(b) Suggest a preventive measure. VIEW SOLUTION

Question 11
(a) List the three states the annuals and biennial angiosperms have to pass through during their life cycle.

(b) List and describe any two vegetative propagules in flowering plants. VIEW SOLUTION

Question 12
Draw a labelled diagrammatic sectional view of a human seminiferous tubule. VIEW SOLUTION

Question 13
During a medical investigation, an infant was found to possess an extra chromosome-21. Describe the symptoms the child is likely to develop later in the life. VIEW SOLUTION

Question 14
A number of passengers were severely burnt beyond recognition during a train accident. Name and describe a modern technique that can help hand over the dead to their relatives. VIEW SOLUTION

Question 15
p² + 2pq + q² = 1. Explain this algebraic equation on the basis of Hardy Weinberg's principle. VIEW SOLUTION

Question 16
(a) What precaution(s) would you recommend to a patient requiring repeated blood transfusion?

(b) If the advise is not followed by the patient, there is an apprehension that the patient might contract a disease that would destroy the immune system of his/her body. Explain with the help of schematic diagram only how the immune system would get affected and destroyed. VIEW SOLUTION

Question 17
(a) What is inbreeding depression?

(b) Explain the importance of "selection" during inbreeding in cattle. VIEW SOLUTION

Question 18
Describe how do 'flocs' and 'activated sludge' help in Sewage Treatment. VIEW SOLUTION

Question 19
Explain the role(s) of the following in biotechnology:

(a) Restriction endonuclease
(b) Gel − electrophoresis
(c) Selectable markers in pBR322 VIEW SOLUTION

Question 20
Write the steps you would suggest to be undertaken to obtain a foreign-gene-product. VIEW SOLUTION

Question 21
Why do lepidopterans die when they feed on Bt cotton plant? Explain how does it happen. VIEW SOLUTION

Question 22
'in-situ' Conservation can help endangered/threatened species. Justify the statement.

OR

Name and describe any three causes of bio-diversity losses. VIEW SOLUTION

Question 24
Read the following statement and answer the questions that follow : (5)

"A guava fruit has 200 viable seeds."

(a) What are viable seeds?

(b) Write the total number of :

(i) Pollen grains (ii) Gametes

in producing 200 viable guava seeds.

(c) Prepare a flow-chart to depict the post-pollination events leading to viable-seed production in a flowering plant.

OR

(a) Arrange the following hormones in sequence of their secretion in a pregnant woman.

(b) Mention their source and the function they perform :

hcG, LH, FSH, Relaxin VIEW SOLUTION

Question 25

State and explain the "law of independent assortment" in a typical Mendelian dihybrid cross. (5)

OR

(a) How do the observations made during moth collection in pre- and post- industrialized era in England support evolution by Natural Selection?

(b) Explain the phenomenon that is well represented by Darwin's finches other than natural selection.
VIEW SOLUTION

Question 26
(a) What is an age-pyramid?

(b) Name three representative kinds of age-pyramids for human population and list the characteristics for each one of them.

OR

Discuss the role of healthy ecosystem services as a pre-requisite for a wide range of economic, environmental and aesthetic goods and services. VIEW SOLUTION

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