Question Set C

cbse 12th Standard Biology Biodiversity and Conservation Model Questions Papers Study Material - QB365

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Questions:

How many pollen grains and ovules are likely to be formed in the anther and the ovary of an angiosperm bearing 25 microspore mother cells and 25 megaspore mother cells, respectively.

Why it is necessary to check the population growth?

Give an example of a somatic hybird proced.

Would you choose an exonuclease for producing a recombinant DNA molecule?

Name biotic agencies of pollination.

Enlist the steps of controlled cross-pollination. Would emasculation be needed in a cucurbit plant? Give reasons for your answer.

What are the consequences of lower genetic diversity?

In a pond there were 30 Hydrilla plants. Through reproduction 10 new Hydrilla plants were added in a year. Calculate the birth rate of population.

What is codon?

10.

Define biopesticides.

11.

What is "afterbirth".

12.

Name the drugs obtained from Hemp plant

13.

(a) A normal couple gave birth to one haemophilic son and two normal daughters. Work out the cross to show the genotypes of the parents and their progeny.
(b) Give the possible genotypes of the parents who can give birth to haemophilic daughters.

14.

Explain the basis on which the gel electrophoresis technique works. Write and two ways the products obtained through this technique can be utilised.

15.

(a) Draw a sectional view of seminiferous tubule of a human. Label the following cells in the seminiferous tubule:
(i) Cells that divide by mitosis to increase their number
(ii) Cells that undergo meiosis I
(iii) Cells that undergo meiosis II
(iv) Cells that help in the process of spermiogenesis.
(b) Mention the role of Leydig cells.

16.

What are analogous organs? Give examples.

17.

Distinguish between ectotherms and endotherms.

18.

Mention any four diseases that can be treated by antibiotics.

19.

Write a short note on fragmentation.

20.

Diseases like dysentary, cholera, typhoid,etc. are more common in overcrowded human settlements.Why?

21.

Give a labelled diagram of pistil showing in it the path of male gametophyte from the stigma to embryo sac.

22.

List components of honey

23.

What is interest-sensitive speciesism? Is it one of the ethical issue related to transgenic animals?

24.

What is hybrid vehicle technology? Explain its advantages with a suitable example?

25.

Make a table showing a few human genetic disorders, their genetic basis, symptoms and effects.

26.

Find out through internet and popular science articles whether animals other than man has self-consciousness.

27.

Although AIDS is a fluid transmitted disease, it is considered as an STD. Give a reason for it.

28.

State the cause of adenosine deaminase enzyme deficiency.

29.

In a court of law, two couples X and Y, claim a child Z of blood group O as theirs. Couple X has man with blood group O and woman with blood group AB. Couple Y has man with blood group A and woman with blood group B. So, a geneticists helps in solving the problem but the judge ordered for use of more recent and advance techniques and then the child was handed over ultimately to couple Y.
(i) Is it a correct judgement regarding the true/biological parents of the child? Justify with your knowledge of genetics.
(ii) Name the other technique that the judge has ordered for solving this problem.
(iii) Indicate the value(s) exhibited by the judge.

30.

A number of pest and disease resistant varieties of crop plants have been developed during recent years for increasing the agricultureal yield. However there are some side effects of such an increased agricultural production. This has led to development of super pest and super weed which are not controlled by routine method. They require some special scientific inputs to control them.
Answer the following questions based on the above information.
(i) Should such a practise of pest control continue?
(ii)What other methods should be practised to manage the pest and diseases to increase the agricultural yield.
(iii)What values have not been exhibited in above case.

31.

Diagrammatically explain the steps of rDNA technology.

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Answers Key:

()
100 pollen grains and 25 embryo sacs.

()
It is necessary to check the population growth for the following resons:
(i) to reduse pressure on the agriculture.
(ii) to maintain the natural resources
(iii) to alleviate social problems like housing,employment etc.
(iv) to have a reproductively heathy society.

()
Pomato (a hybird between potato and tomato).

()
No, because exonucleases will remove the nucleotides from the ends DNA molecule and not at any particular desired region.

()
(i) Insects
(ii) Birds and
(iii) Bats.

()
(a) 1. Selection of parents.
2. Emasculation of flowers of female parent.
3. Bagging of flowers.
4. Collection of pollen from flowers of male parent.
5. Dusting of pollen on the stigmas of female parent.
6. Rebagging, collection of fruits and seeds.
(b) No. Emasculation is not required in cucurbits as they have unisexual flowers. However, bagging is required to prevent contamination.

()
Lower genetic diversity leads to uniformity.

()
Number of individuals added =10 per 20 Hydrilla plants.
\(\frac { 10 }{ 30 } \) = 0.3 offsprings per hydrilla plant per year.

()
A base triplet on mRNA chain which code for one amino acid.

10.

()
Control of pests by biological methods involving biological agents

11.

()
Placenta expelled after delivery.

12.

()
Bhang, Ganja and Charas.

13.

The doctor must have used Pedigree analysis; which refers to the analysis of distribution and movement of traits in a series of generations of a family. Since the non-haemophilic parents give rise to a haemophilic child, the genotypes of them should be

14.

(i) The DNA fragments may be used to construct recombinant DNA by joining them with cloning vectors .
(ii) The desired DNA fragments may be amplified, i.e. making multiple copies, by polymerase chain reaction (PCR).

15.

(b) Leydig cells secrete testosterone, which is necessary for spermatogenesis.

16.

Analogous organs: The organs which are similar in appearance and perform the same function but differ in their fundamental structure and orgin are called analogous organs.
Examples:
1. Wings of birds and insects.
2.Leaves of a plant and cladodes of Ruscus are also analogous organs.

17.

Ectotherms	Endotherms
Ectotherms are those animals whose body temperature changes to match with that of the environment in which they are living.	Endotherms are those animals whose body temperature is maintained relatively constant by physiological regulation.

18.

(i) Diphtheria
(ii) Whooping cough
(iii) Leprosy
(iv) Plague.

19.

Fragmentation. It is a type of asexual reproduction. In some animals like Hydra and Planarian flatworms, there occurs the breaking up of the body into several parts due to one or the other reason. Then each part is called fragment which develops into a complete organism. In some worms and tunicates, it takes place spontaneously.

20.

Over-crowded human settlements are generally with unhygienic conditions due to heaps of garbage,improper disposal of human and animal excreta, stagnant water sources, etc All these conditions increase the chances of spread of infectious diseases like amoebiasis (amoebic dysentary), cholera,typhoid, TB, etc.

21.

22.

Honey is dense sweet liquid, containing sugars 20-40%, moisture 60-80%, minerals 0.22-0.3%, vitamins 0.2-0.5%, enzymes and pollen.

23.

Use of animals in biotechnological research causes greater suffering to the animals. But most people seem accept some animal suffering to serve the basic interest and welfare of mankind this attitude has been termed as interest sensitive speciesism. It is one of the most common ethical issue.

24.

The technology used to run vehicles on dual mode like petrol or compressed natural gas is said to be hybrid vehicle technology. These vehicles runs on either petrol or CNG. As CNG is clean and green fuel so it is helpful to reduce environmental pollution and also to conserve petrol, fossil field.

25.

Some Human Disorders

Disorder	Dominant	Autosomal/Sex- linked	Symptom	Effect
Sickle cell anemia	Recessive	Autosomal (Chromosome 11)	Aggregation of erythrocytes, more rapid destruction of erythrocytes leading to anemia.	Abnormal haemoglobin is RBC's
Phenylketonuria	Recessive	Autosomal (Chromosome 12)	Failure of brain to develop in infancy, mental retardation	Defective form of enzyme phenylalanine hydroxylase
Cystic Fibrosis	Recessive	Autosomal (Chromosome 7)	Mucus clogging in lungs, liver, and pancreas anomalies.	Failure of chloride ion transport mechanism
Huntington's disease	Dominant	Autosomal (Chromosome 11)	Gradual degeneration of brain tissue in middle age	Production of an inhibitor of brain cell metabolism
Haemophilia A/B	Recessive	Sex-linked (X-chromosome)	Failure to blood to clot	Defective from of blood clotting factor \(VIII/IX\)
Colour blindness	Recessive	Sex-linked (X-chromosome)	Failure to discrimination between red and green colour	Defect in either red or/ and green cones.

26.

Yes.
Many animals other than human have self-consciousness. For example, dolphins are highly intelligent. They have a sense of self and they also recognise others among themselves. They can communicate with each other by whistles, tail slapping, and other body movements. Besides dolphins some other animals such as parrots, chimpanzees, orangutans, gorilla, etc. are also found to have self-consciousness.

27.

AIDS is a fluid transmitted disease and is considered as an STD because the probability of fluid transmission is maximum during sexual intercourse.

28.

The adenosine deaminase enzyme deficiency is caused by delection of a gene for ADA, an enzyme crucial for the immune system to function.

29.

(i) yes, the judgment is correct.
Couple X has blood groups O (man) and AB (woman).
Their genotypes and the progeny are as follow:

Thus Couple-X cannot have a child of O group blood, Couple Y has blood group A (man) and b (woman); since the child is O group (ii), both these parents must be heterozygous, i.e. man (I^Ai) and woman (I^Bi).The cross is shown below:

It is possible that child with O-group blood is produced by couple Y.
(ii) DNA-fingerprinting is another technique to solve the paternity cases.
(iii) The judge wanted to be very sure of the parents before pronouncing his judgment; he made his self conscience satisfied.

30.

(i) Such practices of pest and pathogen control although help in increasing the agricultural yield and meet the increasing food demand of the ever increasing population but however they should be allowed and continued only after proper scrutiny and analysis so that the harm to the non target benificial organisms and the environment is minimum.
(ii) Biological control methods of pests and disease control should be preferred in place of the chemical control. The latter are non specific and costly and cause biological magnification while the biocontrol methods are the natural methods of pest and pathogen control and involve the use of natural
predators (e.g., bacteria, fungi) or their products because they are specified and do not harm the non target organisms. For example lady bird beetles brings about the biocontrol of aphid by feeding upon them and Trichoderma a fine living fungus exerts biocontrol on a number of plant pathogens due to its antifungal and antibacterial activity.
(iii) Ethical values with regard to the safety of environment have not been kept in mind.

31.