Bihar Board 12th Biology Model Question Paper 4 in English Medium

Time : 3 Hours 15 Min
Total Marks : 70

Instructions for the candidates:

Candidates are required to give answers in their own words as far as practicable.
Figures in the right-hand margin indicate full marks.
While answering the questions, the candidate should adhere to the word limit as for as practicable.
15 Minutes of extra time has been allotted for the candidates to read the questions carefully.
This question paper is divided into two sections: Section – A and Section – B
In Section – A, there are 35 objective type questions which are compulsory, each carrying 1 mark. Darken the circle with blue/black ball pen against the correct option on OMR Sheet provided to you. Do not use Whitener/Liquid/ Blade/Nail on OMR Sheet otherwise result will be treated as invalid.
In Section – B, there are Non-objective type questions. There are 18 Short answer type questions, out of which any 10 questions are to be answered. Each question carries 2 marks. Apart from this, there are 6 long answer type questions, out of which any 3 of them are to be answered. Each question carries 5 marks
Use of any electronic device is prohibited.

Objective Type Questions

There are 1 to 35 objective type questions with 4 options. Choose the correct option which is to be answered on OMR Sheet. (35 x 1 = 35)

Question 1.
Mendel worked on
(a) Garden pea
(b) Chick pea
(c) Grass pea
(d) None of these
Answer:
(a) Garden pea

Question 2.
Thymus is present near
(a) Heart
(b) Kidney
(c) Liver
(d) Testis
Answer:
(a) Heart

Question 3.
Which among the following antibodies, the Nascent child Obtains maximum from mother’s milk.
(a) Ig A
(b) Ig M
(c) Ig B
(d) Ig E
Answer:
(a) Ig A

Question 4.
10% law for energy transfer in a food chain is given by
(a) Tansley
(b) Weismann
(c) Lindmann
(d) None of the above
Answer:
(c) Lindmann

Question 5.
Causative agent of Dengue fever is
(a) Virus
(b) Bacteria
(c) Protozoa
(d) All of the above
Answer:
(a) Virus

Question 6.
New plants develop from leaves in
(a) Cycas
(b) Eichhornia
(c) Bryophyllum
(d) None of the above
Answer:
(c) Bryophyllum

Question 7.
Phosphorus is important constituent of
(a) Plasma membrane
(b) Nucleic Acid
(c) Cellular energy transport system
(d) All of the above
Answer:
(d) All of the above

Question 8.
Which of the following disease is spread by Protozoan parasite?
(a) Malaria
(b) Kala-azar
(c) Amoebiasis
(d) All of the above
Answer:
(d) All of the above

Question 9.
Fingcrlings and larvae of
(a) Silkworm
(b) Honey bee
(c) Fish
(d) All of the above
Answer:
(c) Fish

Question 10.
Inducer molecule in lac operon of E. Coli is chemically.
(a) Amino acid
(b) Disaccharides
(c) Protein
(d) All of the above
Answer:
(b) Disaccharides

Question 11.
In a natural Ecosystem decomposition takes place by
(a) Parasitic Algae
(b) Virus
(c) Bacteria and Fungi
(d) All of the above
Answer:
(c) Bacteria and Fungi

Question 12.
PCR technique is routinely used to detect
(a) Cancer
(b) T.B.
(c) HIV
(d) All of the above
Answer:
(c) HIV

Question 13.
Production of fruit without fertilization is known as
(a) Apomixis
(b) Apogamy
(c) Parthenogenesis
(d) None of the above
Answer:
(c) Parthenogenesis

Question 14.
Chiasma formation occurs during
(a) Amitosis
(b) Mitosis
(c) Meiosis
(d) None of the above
Answer:
(c) Meiosis

Question 15.
Acrosome is a part of
(a) Spermatozoa
(b) RNA
(c) DNA
(d) All of the above
Answer:
(a) Spermatozoa

Question 16.
Biogas contains
(a) H₂S
(b) CH₄
(c) CO₂
(d) All of the above
Answer:
(b) CH₄

Question 17.
How many structural genes are present in lac- operon in E. coli?
(a) 4
(b) 2
(c) 3
(d) None of the above
Answer:
(c) 3

Question 18.
Ozone layer is found in
(a) Troposphere
(b) Stratosphere
(c) Mesosphere
(d) Exosphere
Answer:
(b) Stratosphere

Question 19.
Mendel’s Monohybrid ratio is
(a) 1 : 2
(b) 3 : 1
(c) 9 : 3 : 3 : 1
(d) All of the above
Answer:
(b) 3 : 1

Question 20.
Ta jmahal located in Agra is in danger due to which gas?
(a) CO₂
(b) NO₂
(c) SO₂
(d) CFC
Answer:
(c) SO₂

Question 21.
Which is used to see DNA in laboratory?
(a) Aniline
(b) Carmine
(c) Ithidium Bromide
(d) All of the above
Answer:
(c) Ithidium Bromide

Question 22.
Pyramid of energy is always
(a) Upright
(b) Downward
(c) Both
(d) None of the above
Answer:
(a) Upright

Question 23.
An organism with two identical alleles is said to be
(a) Homozygous
(b) Heterozygous
(c) Dominant
(d) Hybrid
Answer:
(a) Homozygous

Question 24.
Bacteriophase kills
(a) Fungi
(b) Parasites
(c) Bacteria
(d) Viruses
Answer:
(c) Bacteria

Question 25.
Which of the following is used in ELISA test?
(a) Endonuclease
(b) Polymerase
(c) Ligase
(d) Peroxydase
Answer:
(d) Peroxydase

Question 26.
Catla fish is found in
(a) Fresh water
(b) Hard water
(c) Both a and b
(d) None of the above
Answer:
(a) Fresh water

Question 27.
Which of the following fixes nitrogen in Symbiotic association?
(a) Chana
(b) Volvox
(c) Rhizobium
(d) None of the above
Answer:
(c) Rhizobium

Question 28.
Which on of the following is active in treatment of sewage?
(a) Fishes
(b) Fish
(c) Bacteria
(d) All of the above
Answer:
(c) Bacteria

Question 29.
Smoking causes
(a) Asthama
(b) Bronchitis
(c) Lung disease
(d) All of the above
Answer:
(d) All of the above

Question 30.
Which of the following study is called Oncology?
(a) Leprosy
(b) Cholera
(c) Cancer
(d) All of the above
Answer:
(c) Cancer

Question 31.
Elephantiasis is called as
(a) Malaria
(b) Filaria
(c) Kala-azar
(d) All of the above
Answer:
(b) Filaria

Question 32.
Which of the following causes Ozone hole?
(a) Ethylene
(b) Acetylene
(c) Chloro-florp carbon
(d) All of the above
Answer:
(c) Chloro-florp carbon

Question 33.
The process of producing immunity in the body is called
(a) Immunity
(b) Immunization
(c) Allergy
(d) All of the above
Answer:
(b) Immunization

Question 34.
Which of the following is the copper releasing IUD
(a) Lippes loop
(b) Progestasert
(c) LNG 20
(d) CUT
Answer:
(d) CUT

Question 35.
Chiasma formation occurs during
(a) Amitosis
(b) Mitosis
(c) Meiosis
(d) None of the above
Answer:
(c) Meiosis

Non-Objective Type Questions

Short Answer Type Questions

In this section, there are 18 short answer type question (each carryies 2 marks) out of which answers any ten (10) questions. (10 x 2 = 20)

Question 1.
What is Bt cotton?
Answer:
Bt cotton-Bt cotton is a type of toxin, which is obtained from Bacillus thuringiensis. It is called Bt in short form. Bt toxin gene has been cloned from the bacteria and expressed in plants to provide resistance from insects without the requirement of insecticide. Bt toxin genes were isolated from Bacillus thuringiensis and incorporated into the several crop plants such as cotton.

Question 2.
What measures should be opted to prevent from contracting sexually transmitted diseases ?
Answer:
For prevention of sexually transmitted diseases following actions should be opted :

Avoid sex with unknown partner/multiple partners.
Always use condoms during coitus.
In case of doubt, should go to a qualified doctor for early detection and get complete treatment if diagnosed with disease.

Question 3.
Write short notes on Golden rice.
Answer:
Golden rice is a genetically modified variety of rice. It contains the transgenes from the daffodil plants and also from some bacteria which are responsible for the synthesis of (3-carotene which is a component of Vitamin A. Deficiency of vitamin A causes blindness. Therefore, P-carotene present in golden variety of rice can be helpful in preventing the child blindness.

Question 4.
Describe the disease transmitted through blood transfusion.
Answer:
AIDS is a blood-transfusion transmitted disease caused by Human Immuno deficiency Virus (HIV) in which the natural immune system of the body is destroyed and body is infected with various pathogens.

Question 5.
What is tumor ?
Answer:
When cancerous cells by their division from a storage of cells, it is called tumor. Tumor are of two types –
1. Benign, 2. Malignant.

Benign Tumor – They are restricted to a limited portion and do not extend in other parts of the body.
Malignant – They can easily spread to different parts of the body and their cells are known as Neoplastic cells.

Question 6.
(i) What is noise pollution ? What are its various sources ?
(ii) What are its effects on human beings ?
(iii) Give some methods to control noise pollution.
Answer:
(i) Noise Pollution : It is the unwanted sound which is dumped into the atmosphere and it interferes with human communication, comfort and health.
Sources : Vehicles, musical horns, machines, transistors, radio, drum, beats of religious processions, amplified rock music and disco etc.

Question 7.
Why we say energy flow in the biosphere is unidirectional?
Answer:
The main source of energy of biosphere is ‘Sun’. During photosynthesis solar energy is converted into the chemical energy in the plants. Plants are consumed by herbivores and chemical energy of plants is partially transferred to herbivores animals. Carnivores consume herbivorous animals, their chemical energy of herbivores is transferred to carnivores. That is why, we can say that flow of energy in the biosphere is unidirectional.

Question 8.
Enumerate the major criterias for self-pollination.
Answer:
In which there is transfer of pollen grains from anther to stigma of same flower or another flower of same plants.

It is found in bisexual plants only.
It may occur in Cleistogamous flowers.
There is no need of pollinating agent in it.

Question 9.
Differentiate between DNA and RNA.
Answer:

DNA	RNA
1. DNA is a genetic	1. It is not a genetic material, exception Virus.
2. De-oxyribose sugar is present.	2. Ribose sugar present.
3. Pyrimidine base thymine is present.	3. Uracil in place of thymine.
4. It is double helical	4. It is a single helical structure.

Question 10.
Describe the post-fertilization changes in a flower.
Answer:
During fertilization, the pollen tube reaches into the ovule through the micropyle. One of the two gametes, one joins with the egg cell resulting in the production of zygote. This is called syngamy and other with the two polar nuclei producing triploid primary endosperm nucleus. This is called as triple fusion. This completes the process of fertilization. After fertilization, the ovule converts into the seed and the whole ovary develops into a complete fruit. The ovary wall forms.

Question 11.
Write principles of Biotechnology.
Answer:
Principles of Biotechnology :
Biotechnology is based on two main techniques
(i) Genetic engineering-It is the science of manipulation of genes. In a strict sense it involves alterations in the chemistry of genetic material, introduction of the same into host and thereby changing the phenotype of host.

(ii) Biochemical engineering processes devoted for the growth of desired microbe or eukaryotic cell in large quantities in a culture medium in aseptic conditions for the manufacture and multiplication of biotechnological products, such as antibiotics, vaccines, enzymes etc.

Question 12.
Differentiate between Innate and Acquired Immunity?
Answer:
Innate immunity is a kind of non-specific protection of the body which persist from the birth whereas acquired immunity is pathogen-specific in which primary and secondary responses occur which depend upon memory of the primary responses.

Question 13.
Name the hormones invovled in regulation of spermatogenesis.
Answer:
The hormones involved in the regulation of spermatogenesis one follicle stimulating hormones (F.S.H.) and Lutenizing stimulating hormones (L.S.H.) which are secreted by pituitory gland under the influence of gondotropin releasing hormones from the hypothalamus.

Question 14.
Describe about Parthenium Weed.
Answer:
Parthenium is a genus of North American shrubs. Parthenium invades disturbed land including roadsides. It infests pastures and form land causing after disastrous loss of yield. As an invader it first appeared as a contaminant in imported wheat. The plant produces Allelopathic chemical that suppress crop and pasture plants and allergens that affect humans and livestock. It also causes pollen allergies. But, it may be used as a remedy of skin inflammation, diarrhoea, dysentery and malaria etc.

Question 15.
What is Tranquilizers? Explain it with examples.
Answer:
Drugs which are used in patients having mental tension & worries are called tranquilizers.
For example :

Benzodiazepins-Used in case of mental patient and gives mental peace to them.
Phenothiazines-It stimulate the patient and gives mental peace through eradicating mental worriness.
Reserpine-It is obtained from Rauvolfia serpentina and very effective in mental tension and worriness.

Question 16.
List few important uses of Human Genome Project.
Answer:
(i) The genetic make up of an organism or an individual lies in the DNA sequence. The knowledge about the effect of DNA variations among individuals can lead to revolutionary new ways to diagnose, treat and prevent thousands of disorders that affect human beings.

(ii) The learning about non-human organisms, DNA sequences can lead to understanding of their natural capabilities that can be applied towards solving challenges in health care, agriculture and energy production etc.

Question 17.
Draw a labelled diagram of human male reproductive system.
Answer:

Question 18.
Describe the structure of biogas plant. Give various steps involved in obtaining biogas.
Answer:
Biogas plants consists of a concrete tank (10-15 feet deep) in which bio-wastes are collected and a slurry of dung is fed. A floating cover is placed over the slurry which keeps on rising as the gas is produced. The biogas plant has an outlet for supply of biogas and another outlet for removing slurry.
Steps :

Slurry of animal dung (dung + water) is fed into the digester.
In the digester, microbes break down or decompose the complex compounds of the biomass in the slurry.
Thd anaerobic microbes do not require oxygen, so the digesters are designed like a sealed chamber.
The process takes a few days and gases like methane, CO₂, hydrogen and hydrogen sulphide are produced.

Long Answer Type Questions

There are 6 long answers type question (each carrying 05 marks) out of which answers any three questions. (5 x 3 = 15)

Question 19.
What is pollination? Give an account of the varied means of cross-pollination in plants.
Answer:
Transfer of pollen grains after sheding from the anther to the stigma of the carpel is called pollination.
Pollination in flowering plants occurs by two methods:

Self Pollination and
Cross-Pollination.

(1) Self Pollination – Self pollination involves the transfer of pollen grains from the anther of the flower to the stigma of the same flower or another flower of the same plant.

(2) Cross Pollination – Cross pollination involves the transfer of pollen grains from the flower of one plant to the stigma of the flower of another plant.

Varied means of cross pollination in plants are:

(a) Dicliny – Cross-pollination always occurs when the plants are unisexual and dioecious. Ex-Papaya.
(b) Self Sterility – When the stigma of the gynoecium of a flower is not pollinated by pollen grains of the same flower. Ex-Pea, Potato etc.
(c) Dichogamy – When maturity of male and female parts of a bisexual flower occurs in different times. It is of two types : (i) Protogyny (when gynoecium matures first. Ex-Banyan) and (ii) Protandry (when androecium matures first. Ex:-Maize)
(d) Herkogamy – In some flowers physical barrier present between anther and stigma which avoid self-pollination. Ex-Calotropis
(e) Heterostyly – The flowers of some plants have different lengths of stamens and styles so their self-pollination is not possible. Ex-Primula, Oxalis etc.

Question 20.
What is adaptation? Describe the different types of adaptation in plants of deserts.
Answer:
Adaptation is an attribute of the organism to survive and reproduce in its habitat. Many adaptations have evolved over a long evolutionary time and are genetically fixed. It is of two types-temporary and permanent, e.g. Shrinking of pupil due to bright light is temporary adaptation while change of fore-limbs in feathers for fly in birds is permanant adaptation.

Following adaptations are found in plants of deserts

(a) Its roots are long, thick and goes deep in the soil.
(b) Its stems are fleshy and thick for storage of water.
(c) To check loss of water due to vapourisation, stems are generally cuticulised and fill with dense hairs.
(d) Leaves are changed into small scales and spines, which decreases loss of water due to vapourisation. .
(e) Leaves have suitable tissues for storage of water.
(f) Stomata are embedded in stomatal cavity.
Example of Xerophytic plants are-Opuntia, Euphorbia, Argemone, etc.

Question 21.
Describe the properties of genetic code.
Answer:
The properties of genetic code are as follows :
(a) Triplet nature – The genetic code is a triplet code which is arranged in a sequence on m-RNA.
(b) Unambiguous and Specific-One codon codes for only one amino acid, hence it is unambiguous and specific.
(c) Degenerate code – Some amino acids are coded by more than one codon, hence the code is degenerate.
(d) Commaless form – There are no comma and punctuation marks between the coding triplets (Codons).
(e) Universal – The code is nearly universal. For example, from bacteria to human UUU would code for Phenylalanine (Phe).
(f) Nonsense or Terminator Codon – Three of the 64 codons, namely UAA, UAG and UGA, do not specify any amino acids, but signals the end of the message.
(g) Initiation codon – AUG and sometime GUG are the initiator codon. As AUG stands for methionine, polypeptide chain begins with methionine when they are synthesized.

Question 22.
Define Biodiversity. Describe in brief any three important components of Biodiversity.
Answer:
Biodiversity is the variation of life at all levels of biological organization. In other words variability found in different forms of life like plants, animals and microorganisms and in their genes are called as biodiversity. It voluntarily integrates terresterial, aquatic and ecosystem diversity.

There are three basic components of biodiversity :-

Genetic diversity
Species diversity
Ecological diversity.

(d) Genetic diversity-Genetic diversity is related to the variations of genes within species. A single species might show high diversity at the genetic level over its distributional range. For example, genetic variations shown by the medicinal plant Rauwolfia vomitoria growing in different Himalayan ranges might be in terms of the potency and concentration of the active chemical (reserpine) that the plant produces. India has more than 50,000 genetically different strains of rice and 1,000 varieties of mango.

(e) Species diversity-The diversity at the species level is called species diversity. For example, the Westerm Ghats have a greater amphibian species diversity than Eastern Ghats. Similarly, taking example of plants, Brinjal {Solatium melanogena) Potato (Solarium tuberosum) and Tomato (Solatium lycopersicon) belong to the same genus Solatium but they all too differ at the species level.

(f) Ecological diversity-The diversity at the ecosystem level is called ecological diversity. It is related to the different types of ecosystems, e.g., terrestrial (deserts, rain forest, grass land, etc.) and aquatic (rivers, ponds, lakes, sea, etc.) ecosystems.

Ecological diversity is of three types-Alpha (α), Beta (β) and Gamma (γ) diversity.

(i) Alpha diversity – It refers to the diversity of those organism which belongs to same community and habitat.

(ii) Beta diversity – Diversity between different communities of same habitat is called Beta diversity. If there is more heterogeneity in the habitats in a region or more dissimilarity between communities, there will be more Beta diversity.

(iii) Gamma diversity – Diversity at landscape level is called Gamma diversity. It envolves both types of diversity- alpha and beta. It refers to the diversity of the habitats in the whole geographical region.

Question 23.
How microbes are essential for human welfare? Explain it in detail.
Answer:
Microbes are essential for human welfare because they help through various ways in promotion of our health, foods, agro products and reduction of pollution level as well. These are illustrated below

(a) Microbes are essential for production of dairy products like paneer, curd, butter etc. which are processing products of milk. Production is carried out by the microbes such as bacteria. Similarly bread, idli, vinegar are produced by the activity of microbes.

(b) By using Mithanogen bacteria, production of biogas is possible.

(d) In the field of industries, by activity of microbes, we obtain alcoholic drinks of ionous type, organic acids, vitamin B₂, and B₁₂, dextrins, steroid, amino acids, cyclosporin etc. which all enhances our life.

(e) Microbes are used in the field of treatment against infectious diseases.

(f) In the field of agriculture, microbes are used to increase production of agriculture. We uses microbes as pesticides, weedicides which improve our environmental health.

(g) Microbes are also used as ‘single cell protein’ which fulfills our protein requirements.

Question 24.
Give an account of molecular diagnosis.
Answer:
For effective treatment of a disease, early diagnosis and understanding its pathophysiology is very important. Using conventional method of diagnosis (serum and urine analysis), early detection is not possible. Recombinant DNA technology, polymerase chain reaction (PCR) and Enzyme linked Immuno Sorbent Assay (ELISA) are some of the techniques that serves the purpose of early diagnosis.

Very low concentration of pathogen (bacteria, viruses) can be detected in early stage by application of their nucleic acid by PCR. PCR is now routinely used to detect HIV in suspected AIDS patients. It is being used to detect mutations in genes in suspected cancer patients too. It is powerful technique to identify many other genetic disorder.

ELISA is based on the principle of antigen-antibody interaction. Infection by pathogen can be detected by the presence of antigens (proteins, glyco-proteins) or by detecting the antibodies synthesised against the pathogens. Hybridoma technology is also used to produce monoclonal antibody to detect microscopic pathogens.