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Biology Delhi Set 1 2012-2013 CBSE (Commerce) Class 12 Question Paper Solution

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Biology [Delhi Set 1]
Marks: 70Date: 2012-2013 March

[1]1

An anther with malfunctioning tapetum often fails to produce viable male gametophytes. Give any one reason.

Concept: Pre-fertilisation - Structures and Events - Stamen, Microsporangium and Pollen Grain
Chapter: [1.02] Sexual Reproduction in Flowering Plants
[1]2

Why sharing of injection needles between two individuals is not recommended?

Concept: Human Health and Diseases (Questions)
Chapter: [3.01] Human Health and Diseases
[1]3

Name the enzyme and state its property that is responsible for continuous and discontinuous replication of the two strands of a DNA molecule

Concept: Replication - The Experimental Proof
Chapter: [2.02] Molecular Basis of Inheritance
[1]4

Identify the examples of convergent evolution from the following: 

(i) Flippers of penguins and dolphins

(ii) Eyes of octopus and mammals

(iii) Vertebrate brains

Concept: Evolution (Questions)
Chapter: [2.03] Evolution
[1]5

Write the importance of MOET.

Concept: Animal Husbandry
Chapter: [3.02] Strategies for Enhancement in Food Production
[1]6

Why is the enzyme cellulase needed for isolating genetic material from plant cells and not form the animal cells?

Concept: Tools of Recombinant Dna Technology - Restriction Enzymes
Chapter: [4.01] Biotechnology - Principles and Processes
[1]7

Name the type biodiversity represented by the following: 

(a) 50,000 different strains of rice in India.

(b) Estuaries and alpine meadows in India

Concept: Concept of Biodiversity
Chapter: [5.03] Biodiversity and Its Conservation
[1]8

Write the equation that helps in deriving the net primary productivity of an ecosystem.

Concept: Productivity
Chapter: [5.02] Ecosystem
[2]9

Geitonogamous flowering plants are genetically autogamous but functionally cross-pollinated. Justify.

Concept: Pre-fertilisation - Structures and Events - Pollination
Chapter: [1.02] Sexual Reproduction in Flowering Plants
[2]10

When and where do chorionic villi appear in humans?

Concept: Pregnancy and Embryonic Development
Chapter: [1.03] Human Reproduction

State the Function of Chorionic Villi

Concept: Pregnancy and Embryonic Development
Chapter: [1.03] Human Reproduction
[2]11

In a cross between two tall pea plants some of the offsprings produced were dwarf. Show with the help of Punett square how this is possible.

Concept: Elementary Idea of Polygenic Inheritance
Chapter: [2.01] Principles of Inheritance and Variation
[2]12

A student on a school trip started sneezing and wheezing soon after reaching the hill station for no explained reasons. But, no return to the plains, the symptoms disappeared. What is such a response called? How does the body produce it?

Concept: Pre-fertilisation - Structures and Events - Stamen, Microsporangium and Pollen Grain
Chapter: [1.02] Sexual Reproduction in Flowering Plants
[2]13

Name two commonly used bioreactors.

Concept: Processes of Recombinant Dna Technology
Chapter: [4.01] Biotechnology - Principles and Processes

State the importance of using a bioreactor.

Concept: Processes of Recombinant Dna Technology
Chapter: [4.01] Biotechnology - Principles and Processes
[2]14

Write the function of adenosine deaminase enzyme.

Concept: Biotechnological Applications in Medicine
Chapter: [4.02] Biotechnology and Its Application

State the cause of ADA deficiency in humans.Mention a possible cure for an ADA deficiency patient.

Concept: Biotechnological Applications in Medicine
Chapter: [4.02] Biotechnology and Its Application
[2]15 | Attempt any one of the following
[2]15.1

Expand the Given and mention one application of each:

PCR

Concept: Biotechnological Applications in Medicine
Chapter: [4.02] Biotechnology and Its Application

Expand the Given and mention one application of each:

ELISA

Concept: Biotechnological Applications in Medicine
Chapter: [4.02] Biotechnology and Its Application
[2]15.2

Mention the difference in the mode of action of exonuclease and endonuclease.

Concept: Tools of Recombinant Dna Technology - Restriction Enzymes
Chapter: [4.01] Biotechnology - Principles and Processes

How does restriction endonuclease function?

Concept: Tools of Recombinant Dna Technology - Restriction Enzymes
Chapter: [4.01] Biotechnology - Principles and Processes
[2]16

Name any two sources of e-Wastes and write two difference ways of their disposal.

Concept: Radioactive Waste Management and E-waste
Chapter: [5.04] Environmental Issues
[2]17

Why the pyramid of energy is always upright? Explain.

Concept: Ecological Pyramids
Chapter: [5.02] Ecosystem
[2]18

Explain why very small animals are rarely found in polar region.

Concept: Organism and Its Environment - Responses to Abiotic Factors
Chapter: [5.01] Organisms and Populations
[3]19

Draw a diagram of the microscopic structure of human sperm. Label the following parts in it and write their functions

(a) Acrosome

(b) Nucleus

(c) Middle piece

Concept: Gametogenesis
Chapter: [1.03] Human Reproduction
[3]20

With the help of any two suitable examples explain the effect of anthropogenic actions on organic evolution.

Concept: Evidences for Evolution
Chapter: [2.03] Evolution
[3]21

Why is human ABO blood group gene considered a good example of multiple alleles?

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

Work out a cross up to F1 generation only, between a mother with blood group A (Homozygous) and the father with blood group B (Homozygous). Explain the pattern of inheritance exhibited.

Concept: Deviations from Mendelism - Incomplete Dominance, Co-dominance, Multiple Alleles and Inheritance of Blood Groups, Pleiotropy
Chapter: [2.01] Principles of Inheritance and Variation
[3]22

Describe the structure of RNA polynucleotide chain having four different types of nucleotides.

Concept: Structure of Nucleotide
Chapter: [2.02] Molecular Basis of Inheritance
[3]23

Differentiate between inbreeding and outbreeding in cattle.

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

State the disadvantage of inbreeding among cattle. How it can be overcome?

Concept: Animal Husbandry
Chapter: [3.02] Strategies for Enhancement in Food Production
[3]24

Why are the fruit juices bought from market clearer as compared to those made at home?

Concept: Microbes in Industrial Production
Chapter: [3.03] Microbes in Human Welfare

Name the bioactive molecules produced by Trichoderma polysporum and Monascus purpureus.

Concept: Microbes as Biocontrol Agents
Chapter: [3.03] Microbes in Human Welfare
[3]25

Why a transgenic animals so called?

Concept: Transgenic Animals
Chapter: [4.02] Biotechnology and Its Application

Explain the role of transgenic animals in (i) Vaccine safety and (ii) Biological products with the help of an example each.

Concept: Transgenic Animals
Chapter: [4.02] Biotechnology and Its Application
[3]26 | Attempt any of the following
[3]26.1

How have human activities caused desertification? Explain.

Concept: Degradation by Improper Resource Utilisation and Maintenance
Chapter: [5.04] Environmental Issues
[3]26.2

How does algal bloom destroy the quality of a fresh water body? Explain.

Concept: Water Pollution and Its Control - Introduction of Water Pollution and Its Control
Chapter: [5.04] Environmental Issues
[3]27

Explain mutualism with the help of any two examples.

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

How is mutualism different from commensalism?

Concept: Population - Population Interactions
Chapter: [5.01] Organisms and Populations
[5]28 | Attempt any one of the following
[5]28.1

Draw a diagrammatic sectional view of a mature anatropous ovule and label the following parts in it:

(i) that develops into seed coat.

(ii) that develops into an embryo after fertilization.

(iii) that develops into an endosperm in an albuminous seed.

(iv) through which the pollen tube gains entry into the embryo sac.

(v) that attaches the ovule to the placenta.

 

Concept: Pre-fertilisation - Structures and Events - The Pistil, Megasporangium (Ovule) and Embryo Sac
Chapter: [1.02] Sexual Reproduction in Flowering Plants

Describe the characteristic features of wind pollinated flowers.

Concept: Pre-fertilisation - Structures and Events - Pollination
Chapter: [1.02] Sexual Reproduction in Flowering Plants
[5]28.2

Draw a diagrammatic sectional view of the female reproductive system of human and label the parts

(i) where the secondary oocytes develop

(ii) which helps in collection of ovum after ovulation

(iii) where fertilization occurs

(iv) where implantation of embryo occurs.

Concept: The Female Reproductive System
Chapter: [1.03] Human Reproduction

Explain the role of pituitary and the ovarian hormones in menstrual cycle in human females

Concept: Menstrual Cycle
Chapter: [1.03] Human Reproduction
[5]29 | Attempt any one of the following
[5]29.1

Describe the asexual and sexual phases of life cycle of Plasmodium that causes malaria in humans

Concept: Common Diseases in Humans
Chapter: [3.01] Human Health and Diseases
[5]29.2

What is plant breeding?

 

Concept: Plant Breeding
Chapter: [3.02] Strategies for Enhancement in Food Production

List the two steps the classical plant breeding involves.

Concept: Plant Breeding
Chapter: [3.02] Strategies for Enhancement in Food Production

How has the mutation breeding helped in improving crop varieties? Give one example where this technique has helped.

Concept: Plant Breeding
Chapter: [3.02] Strategies for Enhancement in Food Production

How has the breeding programme helped in improving the public nutritional health? State two examples in support of your answer.

Concept: Plant Breeding
Chapter: [3.02] Strategies for Enhancement in Food Production
[5]30 | Attempt any one of the following

A child suffering from Thalassemia is born to a normal couple. But the mother is being blamed by the family for delivering a sick baby. 

(a) What is Thalassemia?

(b) How would you counsel the family not to blame the mother for delivering a child suffering from this disease? Explain.

(c) List the values your counselling can propagate in the families.

Concept: Genetic Disorders - Mendelian Disorders
Chapter: [2.01] Principles of Inheritance and Variation

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