CBSE (Commerce) Class 12CBSE
Account
It's free!

User


Login
Create free account


      Forgot password?
Share
Notifications

View all notifications
Books Shortlist
Your shortlist is empty

Question Paper Solutions - Biology 2013 - 2014 CBSE (Commerce) Class 12

Alternate Sets

    

Marks: 70
[1]1

Name the part of the flower which the tassels of the corn- cob represent.

Chapter: [1.02] Sexual Reproduction in Flowering Plants
Concept: Pre-fertilisation - Structures and Events - Pollination
[1]2

Mention any two contrasting traits with respect to seeds in pea plant that were studied by Mendel.

Chapter: [2.01] Principles of Inheritance and Variation
Concept: Elementary Idea of Polygenic Inheritance
[1]3

Why is secondary immune response more intense than the primary immune response in humans?

Chapter: [3.01] Human Health and Diseases
Concept: Concept of Immunity
[1]4

Why is it not possible for an alien DNA to become part of a chromosome anywhere along its length and replicate normally?

Chapter: [2.02] Molecular Basis of Inheritance
Concept: Replication - The Experimental Proof
[1]5

State the role of C peptide in human insulin.

Chapter: [4.02] Biotechnology and Its Application
Concept: Biotechnological Applications in Medicine
[1]6

Name the enzymes that are used for the isolation of DNA from bacterial and fungal cells for recombinant DNA technology.

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

State Gause’s Competitive Exclusion Principle.

Chapter: [5.01] Organisms and Populations
Concept: Population - Population Interactions
[1]8

Name the type of association that the genus Glomus exhibits with higher plants.

Chapter: [3.03] Microbes in Human Welfare
Concept: Microbes as Biocontrol Agents
[2]9

Why are the human testes located outside the abdominal cavity? Name the pouch in which they are present.

Chapter: [1.03] Human Reproduction
Concept: Microscopic Anatomy of Testis
[2]10

In Snapdragon, a cross between true-breeding red flowered (RR) plants and truebreeding white flowered (rr) plants showed a progeny of plants with all pink flowers.

The appearance of pink flowers is not known as blending. Why?

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

In Snapdragon, a cross between true-breeding red flowered (RR) plants and truebreeding white flowered (rr) plants showed a progeny of plants with all pink flowers.

What is this phenomenon known as?

Chapter: [2.01] Principles of Inheritance and Variation
Concept: Deviations from Mendelism - Incomplete Dominance, Co-dominance, Multiple Alleles and Inheritance of Blood Groups, Pleiotropy
[2]11

With the help of one example, explain the phenomena of co-dominance and multiple allelism in human population.

Chapter: [2.01] Principles of Inheritance and Variation
Concept: Deviations from Mendelism - Incomplete Dominance, Co-dominance, Multiple Alleles and Inheritance of Blood Groups, Pleiotropy
[2]12 | Attempt Any One
[2]12.1

Write the scientific name of the fruit-fly. Why did Morgan prefer to work with fruit-flies for his experiments? State any three reasons.

Chapter: [2.01] Principles of Inheritance and Variation
Concept: Genetic Disorders - Mendelian Disorders
[2]12.2

Linkage and crossing-over of genes are alternatives of each other. Justify with the help of an example.

Chapter: [2.01] Principles of Inheritance and Variation
Concept: Inheritance of Two Genes - Linkage and Crossing Over
[2]13

List the symptoms of Ascariasis. How does a healthy person acquire this infection?

Chapter: [3.01] Human Health and Diseases
Concept: Common Diseases in Humans
[2]14

Explain the significant role of the genus Nucleopolyhedrovirus in an ecological sensitive area.

Chapter: [3.03] Microbes in Human Welfare
Concept: Microbes as Biocontrol Agents
[2]15

How does a restriction nuclease function? Explain

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

How have transgenic animals proved to be beneficial in: Production of biological products

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

How have transgenic animals proved to be beneficial in: Chemical safety testing

Chapter: [4.02] Biotechnology and Its Application
Concept: Transgenic Animals
[2]17

Describe the mutual relationship between fig tree and wasp and comment on the phenomenon that operates in their relationship.

Chapter: [5.01] Organisms and Populations
Concept: Population - Population Interactions
[2]18

Construct an age pyramid which reflects an expanding growth status of human population.

Chapter: [5.01] Organisms and Populations
Concept: Population - Population Attributes
[3]19 | Attempt Any One
[3]19.1

Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination.

Chapter: [1.02] Sexual Reproduction in Flowering Plants
Concept: Pre-fertilisation - Structures and Events - Pollination
[3]19.2

Why angiosperm anthers are called dithecous?

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

Describe the structure of its microsporangium.

Chapter: [1.02] Sexual Reproduction in Flowering Plants
Concept: Pre-fertilisation - Structures and Events - Pollination
[3]20

If implementation of better techniques and new strategies are required to provide more efficient care and assistance to people, then why is there a statutory ban on amniocentesis? Write the use of this technique and give reason to justify the ban.

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

If implementation of better techniques and new strategies are required to provide more efficient care and assistance to people, then why is there a statutory ban on amniocentesis? Write the use of this technique and give reason to justify the ban.

Chapter: [1.04] Reproductive Health
Concept: Reproductive Health - Problems and Strategies
[3]21

Why is pedigree analysis done in the study of human genetics? State the conclusions that can be drawn from it.

Chapter: [2.01] Principles of Inheritance and Variation
Concept: Genetic Disorders - Mendelian Disorders
[3]22

Identify 'a', 'b', 'c',’d’, 'e' and 'f' in the table given below:

No. Syndrome Cause Characteristics of  affected individuals Sex
Male/Female/Both
1. Down's Trisomy of 21 'a' (i)
(ii)
'b'
2. 'c' XXY Overall masculine
development.
'd'
3. Turner's 45 with XO 'e' (i)
(ii)
'f'
Chapter: [2.01] Principles of Inheritance and Variation
Concept: Genetic Disorders - Chromosomal Disorders
[3]23

Community Service department of your school plans a visit to a slum area near the school with an objective to educate the slum dwellers with respect to health and hygiene.

(a) Why is there a need to organize such visits?

(b) Write the steps you will highlight, as a member of this department, in your interaction with them to enable them to lead a healthy life.

Chapter: [3.01] Human Health and Diseases
Concept: Infectious and Non Infectious Disease
[3]24

The following graph shows the species - area relationship. Answer the following questions as directed.

(a) Name the naturalist who studied the kind of relationship shown in the graph. Write the observations made by him.

(b) Write the situations as discovered by the ecologists when the value of 'Z'
(Slope of the line) lies between.

(i) 0.1 and 0.2

(ii) 0.6 and 1.2

What does 'Z' stand for?

(c) When would the slope of the line 'b' become steeper?

Chapter: [5.03] Biodiversity and Its Conservation
Concept: Biodiversity - Patterns of Biodiversity
[3]25

Name and describe the technique that helps in separating the DNA fragments formed by the use of restriction endonuclease

Chapter: [4.01] Biotechnology - Principles and Processes
Concept: Tools of Recombinant Dna Technology - Restriction Enzymes
[3]26

State the function of a reservoir in a nutrient cycle

Chapter: [5.02] Ecosystem
Concept: Nutrient Cycling

Explain the carbon cycle with the help of a simplified model.

Chapter: [5.02] Ecosystem
Concept: Nutrient Cycling
[3]27

Since the origin of life on Earth, there were five episodes of mass extinction of species.

How is the ‘Sixth Extinction’, presently in progress, different from the previous episodes?

 

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

Since the origin of life on Earth, there were five episodes of mass extinction of species.

Who is mainly responsible for the 'Sixth Extinction’?

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

Since the origin of life on Earth, there were five episodes of mass extinction of species List any four points that can help to overcome this disaster.

 

Chapter: [5.03] Biodiversity and Its Conservation
Concept: Extinction
[5]28 | Attempt Any One
[5]28.1

Where does fertilization occur in humans? Explain the events that occur during this process.

Chapter: [1.03] Human Reproduction
Concept: Fertilisation and Implantation

A couple where both husband and wife are producing functional gametes, but the wife is still unable to conceive, is seeking medical aid. Describe any one method that you can suggest to this couple to become happy parents

Chapter: [1.03] Human Reproduction
Concept: Embryo Development Upto Blastocyst Formation
[5]28.2

Explain the different ways apomictic seeds can develop, Give an example of each.

Chapter: [1.02] Sexual Reproduction in Flowering Plants
Concept: Apomixis And Polyembryony

Mention one advantage of apomictic seeds to farmers.

Chapter: [1.02] Sexual Reproduction in Flowering Plants
Concept: Apomixis And Polyembryony

Draw a labelled mature stage of a dicotyledonous embryo.

Chapter: [1.02] Sexual Reproduction in Flowering Plants
Concept: Post-fertilisation : Structures and Events - Endosperm
[5]29 | Attempt Any One
[5]29.1

Describe the various steps of Griffith’s experiment that led to the conclusion of the 'Transforming Principle'.

Chapter: [2.02] Molecular Basis of Inheritance
Concept: Search for Genetic Material - Properties of Genetic Material (DNA Versus RNA)

How did the chemical nature of the ‘Transforming Principle' get established?

Chapter: [2.02] Molecular Basis of Inheritance
Concept: Search for Genetic Material - Properties of Genetic Material (DNA Versus RNA)
[5]29.2

Describe how the lac operon operates, both in the presence and absence of an inducer in E.coli.

Chapter: [2.02] Molecular Basis of Inheritance
Concept: Regulation of Gene Expression - The Lac Operon
[5]30 | Attempt Any One
[5]30.1

With advancements in genetics, molecular biology and tissue culture, new traits have been incorporated into crop plants. Explain the main steps in breeding a new genetic variety of a crop

Chapter: [3.02] Strategies for Enhancement in Food Production
Concept: Tissue Culture
[5]30.2

State the objective of animal breeding.

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

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

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

List the importance of inbreeding.

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

Give an example of a new breed each of cattle and poultry.

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