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Question Paper Solutions - Biology 2016 - 2017-CBSE 12th-Class 12 CBSE (Central Board of Secondary Education)

Alternate Sets

   

Marks: 70
[1]1

Our government has intentionally imposed strict conditions for M.T.P. in our country. Justify giving a reason.

Chapter: [1.04] Reproductive Health
Concept: Reproductive Health - Problems and Strategies
[1]2

State the fate of a pair of autosomes during gamete formation.

Chapter: [1.01] Reproduction in Organisms
Concept: Sexual Reproduction - Pre-fertilisation Events - Gametogenesis
[1]3

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

Chapter: [2.03] Evolution
Concept: Evolution of Life Forms - a Theory
[1]4

Suggest a method to ensure an anamnestic response in humans.

Chapter: [3.01] Human Health and Diseases
Concept: Concept of Immunity
[1]5

What is biopiracy?

Chapter: [4.02] Biotechnology and Its Application
Concept: Ethical Issues
[2]6

How does the megaspore mother cell develop into 7-celled, 8 nucleate embryo sac in an angiosperm?

Chapter: [11.01] Human Reproduction
Concept: Embryo Development Upto Blastocyst Formation

Draw a labeled diagram of a mature embryo sac.

Chapter: [11.01] Human Reproduction
Concept: Embryo Development Upto Blastocyst Formation
[2]7 | Attempt any one
[2]7.1

Describe the structure of a nucleosome.

Chapter: [2.02] Molecular Basis of Inheritance
Concept: The DNA - Packaging of Dna Helix
[2]7.2

Mention the evolutionary significance of the Shrews

Chapter: [2.03] Evolution
Concept: Evolution of Life Forms - a Theory

Mention the evolutionary significance of the Lobefins

Chapter: [2.03] Evolution
Concept: Evolution of Life Forms - a Theory

Mention the evolutionary significance of the Homo habilis

Chapter: [2.03] Evolution
Concept: Evolution of Life Forms - a Theory

Mention the evolutionary significance of the Homo erectus

Chapter: [2.03] Evolution
Concept: Evolution of Life Forms - a Theory
[2]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 yiel.

Chapter: [3.01] Enhancement in Food Production
Concept: Plant Breeding
[2]9

How does the application of the fungal genus, Glomus, to the agricultural farm increase the farm output? 

Chapter: [3.03] Microbes in Human Welfare
Concept: Microbes as Biofertilisers
[2]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.

Chapter: [12.01] Organisms and Environment 2
Concept: Water Pollution and Its Control - Introduction of Water Pollution and Its Control
[3]11

List the three states the annuals and biennial angiosperms have to pass through during their life cycle.

Chapter: [1.02] Sexual Reproduction in Flowering Plants
Concept: Flower – a Fascinating Organ of Angiosperms

List and describe any two vegetative propagules in flowering plants.

Chapter: [1.01] Reproduction in Organisms
Concept: Asexual Reproduction
[3]12

Describe the structure of a seminiferous tubule.

Chapter: [11.01] Human Reproduction
Concept: The Male Reproductive System
[3]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.

Chapter: [2.01] Principles of Inheritance and Variation
Concept: Genetic Disorders - Chromosomal Disorders
[3]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.

Chapter: [2.02] Molecular Basis of Inheritance
Concept: DNA Fingerprinting
[3]15

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

Chapter: [2.03] Evolution
Concept: Hardy - Weinberg'S Principle
[3]16

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

Chapter: [3.01] Human Health and Diseases
Concept: AIDS

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.

Chapter: [3.01] Human Health and Diseases
Concept: AIDS
[3]17

What is inbreeding depression?

Chapter: [3.02] Strategies for Enhancement in Food Production
Concept: Animal Husbandry

Explain the importance of "selection" during inbreeding in cattle

Chapter: [3.02] Strategies for Enhancement in Food Production
Concept: Animal Husbandry
[3]18

Describe how do 'flocs' and 'activated sludge' help in Sewage Treatment.

Chapter: [3.03] Microbes in Human Welfare
Concept: Microbes in Sewage Treatment
[3]19

Explain the role of Restriction endonuclease in Biotechnology

Chapter: [4.02] Biotechnology and Its Applications
Concept: Introduction of Biotechnology and Its Application

Explain the role of the Gel − electrophoresis in Biotechnology

Chapter: [4.02] Biotechnology and Its Applications
Concept: Introduction of Biotechnology and Its Application

Explain the role of the Selectable markers in pBR322 in Biotechnology.

Chapter: [4.02] Biotechnology and Its Applications
Concept: Introduction of Biotechnology and Its Application
[3]20

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

Chapter: [4.01] Biotechnology - Principles and Processes
Concept: Tools of Recombinant Dna Technology - Competent Host (For Transformation with Recombinant Dna)
[3]21

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

Chapter: [4.02] Biotechnology and Its Application
Concept: Biotechnological Applications in Agriculture
[3]22

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

Chapter: [5.03] Biodiversity and Its Conservation
Concept: Biodiversity Conservation

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

Chapter: [5.03] Biodiversity and Its Conservation
Concept: Biodiversity Conservation
[4]23

Public all over India is very much concerned about the deteriorating air quality in large parts of North India. Alarmed by this situation the Resident's Welfare Association of your locality organized an awareness programme entitled "Bury not burn". They invited you, being a biology student to participate.

(a) How would you justify your arguments that promote burying and discourage burning? (Give two reasons)

(b) With the help of flow charts, one for each practice depict the chain of events that follow.

Chapter: [5.04] Environmental Issues
Concept: Water Pollution and Its Control - Domestic Sewage and Industrial Effluents
[5]24 | Attempt any one
[5]24.1

Read the following statement and answer the questions that follow : 
"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.
 

Chapter: [1.02] Sexual Reproduction in Flowering Plants
Concept: Sexual Reproduction in Flowering Plants (Questions)
[5]24.2

(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

Chapter: [1.03] Human Reproduction
Concept: Pregnancy and Embryonic Development
[5]25 | attempt any one
[5]25.1

Work out a typical Mendelian dihybrid cross and state the law that he derived from it.

Chapter: [2.01] Principles of Inheritance and Variation
Concept: Deviations from Mendelism - Incomplete Dominance, Co-dominance, Multiple Alleles and Inheritance of Blood Groups, Pleiotropy
[5]25.2

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

Chapter: [2.03] Evolution
Concept: Darwin'S Contribution

Explain the phenomenon that is well represented by Darwin's finches other than natural selection.

Chapter: [2.03] Evolution
Concept: Darwin'S Contribution
[5]26 | attempt any one
[5]26.1

What is an age-pyramid?

Chapter: [5.01] Organisms and Populations
Concept: Population - Population Attributes

Represent diagrammatically three kinds of age-pyramids for human populations.

Chapter: [5.01] Organisms and Populations
Concept: Population - Population Attributes
[5]26.2

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

Chapter: [5.02] Ecosystem
Concept: Ecosystem Services
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