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Previous year question paper with solutions for Biology Mar-2019
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Question paper 1
1. Why is offspring formed by asexual reproduction referred to as clone?
Answer:
The offspring’s formed by asexual reproduction are referred to as alone because they are genetically and morphologically similar.
2. What is meant by satellite DNA?
Answer:
Satellite DNA are tandem repeats of simple DNA sequence. These sequences do not code for ant position. It has been proved as useful genetic marker in DNA finger printing.
3. What is meant by metastasis?
Answer:
The malignant tumor cells grow very rapidly, invading and damaging the surrounding normal issues, cells broken of such tumors reach distant sites through blood and start a tumor there. This property is called metastasis.
4. What do you mean by algal bloom?
Answer:
When there is rapid increase of green algae in a water body, it is termed as algal bloom. This results in increased BOD.
5. Transfer of pollen grains from the anther of flower of one plant to stigma of flower of another plant is called
(a) Autogamy (b) Xenogamy
(c) Geitonogamy (d) Cleistogamy
Answer:
(b) Xenogamy
6. A colour blind male marries a normal female. What percentage of male children of this couple will be colour blind?
(a) 0% (b) 25%
(c) 50% (d) 75%
Answer:
(a) 0%
7. Meaning of prefix 'Bt' in BT cotton is
(a) Bacterial Toxin (b) Biological Toxin
(c) Toxin released by Bacillus thuringienis (d) Biotechnology
Answer:
(c) Toxin released by Bacillus thuringienis
8. Red data book is maintained by
(a) WHO (b) WWF
(c)IUCN (d) CITIES
Answer:
(c)IUCN
9. What is triple fusion? How does it take place?
Answer:
Fusion of mate gamete with secondary nucleus inside the embryo sac (female gametophyte) of angiosperms is called triple fusion. After entering one of the synergies, the pollen tube releases two male gametes into cytoplasm of synergic one of male gametes moves toward the egg cell and fuses with nucleus to complete syngamy while other male gamete move towards the two polar nuclei located in central cell and fuses with them to produce triploid primary endosperm nucleus (PEN)
10. A double-stranded DNA molecule has 20% of cytosine. Using Chargaff's law calculate the percentage of adenine in this DNA molecule.
Answer:
According to Chargaff’s Rule,
Adenine = Thymine
Guano sine = Cytosine
Here, C = 20%
G = 20%
The remaining 60% include both Adenine and Thymine in equal accounts. Therefore, the % age of Adenine is 30%.
11. "Birds have evolved from reptiles" Give palaeontological evidence in favour of this statement.
Answer:
“Birds have evolved from reptiles”. The fossils of Archaeopteryx (Lizard Bird ) were found in rocks of Jurassic period. It is the transitional from between reptiles and birds because it showed characters of both birds and reptiles. The reptiles were developed earlier then birds. The Archaeopteryx shows the link between them proving that birds evolved from reptile like ancestors.
12. What are hallucinogens? Give an example.
Answer:
The drugs that can change thoughts, feeling and perceptions of an individual are known as hallucinogenic properties are Atropa belladonna and Datura.
13. Wat are hallucinogens? Give an example.
Answer:
The yeast Saccharomyces cerevisiae is known as Baker’s yeast. The baker’s yeast is mainly used for preparing bread from wheat flour. The yeast secretes zymase complex which contains no. of enzymes that can convert starch tomatoes maltose to glucose and glucose to ethyl alcohol and
. This makes the bread soft and porous.14. Why is Agrobacterium tumifaciens a good cloning vector for gene cloning? Explain.
Answer:
Agrobacterium tumefactions is a pathogen of several dicot plants. It is also delivery a piece of DNA known as T-DNA to transform normal plants cells into a tumor and direct these tumor cells to produce the chemicals required by pathogens. T-DNA is DNA segment of Ti plasmid (Tumor Inducing plasmid). Biologist use Ti plasmid to transfer foreign gens of interest into targets plant cells.
15. What are 'molecular scissors'? Give an example.
Answer:
The restriction enzymes are known as molecular scissors. These enzymes cut the DNA at specific locations, for example, Restriction endonuclease, Hindi II always cut DNA molecules at a particular point by recognizing specific sequence of six base pairs, Molecular scissor belong to class of enzymes called nucleases.
16. Differentiate between hibemation and aestivation.
Answer:
In animals, the organizes, if unable to migrate, might avoid the stress by escaping in time. If the animals are escaping from winters, it is known as hibernation. For example-: bears go into hibernation to avoid winters. If the animals or organizes are escaping from heat of summers, it is known as aestivation. For example-: snails and fishes undergo aestivation to avoid heat and desiccation.
17. What is amniocentesis? Discuss its use and misuse.
Answer:
Amniocentesis is a fetal sex determination test based on chromosomal pattern in the amniotic fluid surrounding the developing embryo. The amniotic fluid contains tissues that could tell about that sex chromosomes of the fetus.
Uses:- sometimes there are genetic disorders that could possibly be shown in child. Amniocentesis could help to check the genetic disorders in the fetus such as Down’s syndrome etc. Early detection of diseases could help in its prevention.
Misuse:- Many people used the test to know about sex of fetus. Many female fetuses are aborted illegally every year. The illegal abortion of girls fetus is the biggest threat to society.
18. A true-breeding homozygous pea plant with round seeds and yellow cotyledons is crossed with a homozygous pea plant with wrinkled seeds and green cotyledons.
(a) Work out the cross to show the phenotype and genotype ratio of
generations.(b) State the Mendel's generalisation that can be derived from above cross.
Answer:
(a) The cross between homozygous pea plant with winkled seeds and green cotyledons is shown is shown below:-
Yellow Round seeds Green wrinkled seeds
Parents YY RR yy rr
Ganetes YR yr
YyRr(All Yellow Round)
selfing 
Males gametes
Females gametes
YR
Yr
yR
yr
YR
YYRR
(Yellow Round)
YYRr
(Yellow Round)
YyRR
(Yellow Round)
YyRr
(Yellow Round)
Yr
YYRr
(Yellow Round)
YYrr
(Yellow wrinkled)
YyRr
(Yellow Round)
Yyrr
(Yellow wrinkled)
yR
YyRR
(Yellow Round)
YYrr
(Yellow wrinked)
YyRr
(Green Round)
yyRr
(Yellow Round)
yr
YyRr
(Yellow Round)
Yyrr
(Yellow wrinkled)
YyRr
(Yellow Round)
yyrr
(Green wrinkled)
Phenotypic ratio:- (4 Phenotypes)
Yellow : Yellow : Green : Green
Round : Wrinkled : Round : Wrinkled
9 : 3 : 3 : 1
Genotypic ratio:- (9 Genotypies)
1:2:1:2:4:2:1:2:1
(b) From above, Mendel proposed a generalization, that we call as law of Independent Assortment. According to this law, in above cross, the plant of
genotypic have all round and yellow seeds because round and yellow traits are dominant over green and wrinkled traits and on self-breeding 
genotypic 4 type of plants. This shows that factors of each of two characters assort independent of other.19. What do you mean by term Single cell protein? Mention the advantages of using microorganisms for SCP production.
Answer:
Single cell proteins refer to any microbial biomass produced by uni and multicellular micro-organizes and can be used as food or feed additives. Microbes are being grown on an industrial scale as source of good protein microbes like spiruluia can be grown easily on materials like waste water from potato processing (containing starch),straw, molasses, animals manure and we sewage. In this way a large quantity can be produce which can serve as food rich in proteins, minerals, fats, carbohydrates and vitamins.
Advantage:- It has been calculated that 250kg cow produce 200kg of protein per day. The shift from grain to meat also need 3-10kg of more grain to produce 1kg of meat of animal forming. In the same period 250g of micro-organize like Methylophilus methylotrophus can be expected to produce 25 tones of proteins Mushrooms (SCP) are eaten by many people and large scale mushroom culture is a growing industry. This shows that microbes too would become acceptable food.
20. How was insulin before the advent of rDNA technology? Write about various steps involved in production of genetically engineered insulin.
Answer:
Diabetes which start in the adult can be managed by taking insulin at regular intervals. Earlier it was extracted from pancreas of slaughtered pigs and cattle. This inulin is slight by different from human insulin and bring about some side effects like allergy. Genetically Engineered Insulin (Recombinant Insulin (Hamelin)):- In 1983, Eli Lilly an American company prepared two DNA sequences of A and B chairs of human insulin. These were introduced in plasmids of E.Coli to produce insulin chairs. Chains A and B were produced separately. These were extracted and combined by creating disulphide bonds to taken orally because it is a protein and will be digested in gut.
21. State and Explain ten percent law of energy.
Answer:
Except for deep sea hydrothermal ecosystem, sun is the only source of energy for all the ecosystem on the earth of the total incident solar radiations, less than 50% is Photo synthetically active radiations (PAR) plants capture only 2-10 % of PAR There is unidirectional flow of energy from sun to producers and then to consumers. Every ecosystem a contain supply of energy.
There is decrease in content and flow of energy captured by producers is used for maintenance. Only 10% of gross productivity of producers is entrapped by herbivores for their body building. Herbivores are eaten by primary carnivores are able to retain only 10% law of energy which was proposed by Lindeman in 1942.
22. Name the parasite that causes malaria. At what stage of its lifecycle does it enter into human body? Menton the measures that must be taken to control malaria.
Answer:
Malaria is a protozoan disease. The causative agents of various kind malaria are plasmodium species such as plasmodium visas, plasmodium oval, Plasmodium malaria, Plasmodium falciparum.
Life cycle of Plasmodium is digenetic (completed in two hosts). Man is secondary host and female Anopheles is primary host. The life cycle of plasmodium has there phases.
Schizogony is the phase where porosities are inject in the blood of a man along with saliva of infected female Anopheles. It is future divided into two phases as :-
(a) Hepatic schizogony enter liver cells, undergo fission to form cryphtomerozoites which further repeat this cycle.
(b) Erythrocyte schizogony :- cryptomerozoites enter the erythrocytes, eat up their hemoglobin and grow to merozoites which repeat the process. The heave of RBCs is changed into toxic substance called haemiozoin which is responsible for malarial attack (chill and high fever).It reoccurs after a fixed interval of time. The schizogony can be shown as :- (figure below)
Precautions/Preventative Measures:- The following preventative measures could be followed for prevention form malaria :-
1. The doors and windows should be wire gouged to check entry of mosquitoes.
2. Use of insect repellents to prevent mosquito bites.
3. Sleeping under mosquito nets.
4. Killing mosquito larvae by filling ditches etc., sprinkling kerosene oil on water, introducing larsticidal fishes e.g. gambusia and plants as ultricularia.
5. Killing of adult mosquitoes by spraying insecticides like BHC etc.
OR
22. (a) What is autoimmunity? Name anyone autoimmune disease of human beings.
(b) What is chemical composition of biogas?
Answer:
22. (a) Auto immunity:- It is a type of immune disorder when immune system of an individual starts rejecting its own body cells. This leads to variety of diseases called auto immune diseases. It further depends upon the type of ‘self-antigen’ involved. Some auto immune diseases are:-
1. Chronic anemia: - It occurs if auto antigens are RBC, then lymphocytes of system start destroying its own RBC.
2. Chronic hepatitis: - It is caused if self-antigens are liver cells.
(b) Biogas is produced mainly from cow dung; green plants and other organic item have also been used. They are allowed to decompose in a tank. The gas produced is collected in another tank. The biogas mainly constituted of methane along with methane other gases like
are produced in the chambers. Methane (50-85%), (20-35%) and other are amount loss than 10%.23. What are Cry proteins? How has biotechnologist exploited these proteins to benefit farmers?
Answer:
Cry Proteins:- The Bt plants produce genes depending upon crop and targeted pest. The genes produce toxic proteins that are able to kills specific group of insects. These toxic is coded by gene named cry and the protein thus released is called cry protein. These helped the formers in following ways:-
1. They work for specific group of insects that leaves the useful insects unearned.
2. These do not effect with the plant growth and nourishment.
3. It helped to increase the yield of the crops.
OR
23. Briefly write about:
(a) Downstream processing (b) BIoreactors
Answer:
(a) Downstream processing: - After the completion of biosysntic state, the fermented product has to be subjected though a series of processes before it is ready for marketing. The processes include separation and purification. These processes are collectively called downstream processing. Suitable preservation are also added. For medicines, clinical trials are carried out. Strict control testing for each product is also required. The downstream processing and quality control testing vary from product to product.
(b) Bioreactor :- They are also known as fermenters. Small volumes cultures cannot give large quantities of the products. To produce large quantities of these products, development of bioreactors was carried out where large volume (100-1000 liters) of culture can processed. A bioreactor provides the optimal conditions for obtaining the desired product by providing optimum growth conditions such as temp. ph, substrates, vitamins, oxygen and salts.
24. Name the term used for pollination by insects. Give an example of insect pollinated plant. Write any four characters of insect-pollinated plant.
Answer:
The tern used for pollination by insects is Entomophily. Entomophily is a type of zoophile in which the pollen gains of ripe anthers of one flower are transferred to a mature stigma of another flower thought agency of insects. The insects that carry out pollination are moths, butterflies, wasps, bees, beetles etc.
Examples of plants:- The plants in which insects are used for pollination are sun flower, Bougainvillea , Jasmine , Yucca etc.
Characteristics of Entomophillous Flowers:-
1. Flowers are larges, colorful, fragrant.
2. These are rich in nectar.
3. When the flowers are small no. of flowers are clustered into an inflorescence to make them conspicuous, example:- head in sun flowers
4. When petals are not conspicuous, other parts become showy, example:- bracts in Bougainvillea.
5. Most of such flowers have landing platforms.
6. Flowers produce an odor which may be pleasant, example:- jasmine.
7. Nectar is secreted for feeding insects.
8. Some plants produce edible pollens.
9. Usually stamens are inserted.
10. Pollen grains are surrounded by pollen kit.
11. Stigmas are often inserted and sticky.
12. Some flowers provide safe places for insects for laying eggs, example:- Yucca, Amorphophallus.
OR
24. What is oogenesis? When does oogenesis begin in female? Describe briefly the process of oogenesis with help of suitable diagram.
Answer:
Oogenesis:- The process of formation of a mature female gamete (Ovum) is called oogenesis. Oogenesis starts during the fetus in development of female fetus in the ovaries.
Process of Oogenesis:-
Oogenesis can be explained by following phases:-
1. Multiplication Phase:- It starts when female fetus is in the ovaries, some epithelial cells of ovary divide by mitoses to produces couple of million gamete mother cells (orgonia). No more oogonia are formed or added after birth.
Growth phase:- oogonia grows to primary oocyte. It takes period of years. Its cytoplasm increase and nucleus enlarges after puberty.
3. Maturation phase:- Primary oocyte start division and enter to prophase-I of meiotic division. Division stops temporarily here. In meantime oocyte gets surrounded by granulose cells and is called primary follicle. At puberty only 60000- 80000 price follicles are left in each ovary. The grow to secondary follicle then to tertiary follicle and then to Graafian follicle. Meiosis II starts and proceeds up to metaphase II. Here Grafian follicle ruptures to release sec. oocyte from ovary. The sec. oocyte enters fallopian tube and awaits the arrival of sperm.
25. What is an inducible operon? Name the genes that constitute an operon Explain the lac operon of E.Coli with help of schematic representation.
Answer:
Operon:- An operon is a part of genetic material which acts as simple regulation unit having on or more structural genes, an operator gene, a pronator gene etc. An inducer is chemical which after coming in contact with repressor, changes latter into non DNA birding state so as to free the operator gene. The inducer for lac operon of E.cole is lactose or all lactose.
The gene that constitute an operon are structural gene, operator gene, promoter gene, regular gene, repressor gene and an inducer or co-repressor gene.
Lactose addition to E.coli:- A few molecules are carried into cell by enzyme lactose permease. These are convened into an active form which acts as an inducer and binds to repressor. Repressor inducer complex fails to join operator gene. Which is turned on. The three enzymes to metabolize lactose to galactose and glucose.
OR
25. (a) 'Ontogeny repeats phylogeny' justify.
(b) Describe Charles Darwins's theory of natural selection.
Answer:
(B) Darwin put forward the concept of natural selection as the mechanism of evolution. The concept is based on “An essay on population by Malthus (1799). He got idea of natured selection from artificial selection performed by man to make many breeds of organisms. The salient features is selected over the weak one or the fittest survives. The weak one or the fittest survives. The organisms reproduce at very high rate but these is very limited food and space on earth for survival. Due to limited resources, the organisms struggle for their existence which one another in same species (Intraspecific), with other (Intraspecific) and also with environment. These struggles make differences among some individuals called as variations. The variations that are more useful .acc. to environmental condition will be carried out to next generations. This is known as the Natural Selection by Darwin.
26. What do you means by interspecific interactions? Examlain different types of positive interactions in biotic communtiy.
Answer:
OR
26. Write short notes on:
(a) e-waste
(b) Ozone layer depletion
(c) REd databook
Answer:
(a) E-waste:- In today’s world, we depend too much on the technology. Most of the people depend upon machines for their work need. When these machines are of no use or get damaged, they are thrown out in the dumps. These machines mainly include computer parts, mobile phone, laptops, washing machines, fax machines etc. These all machines are electronic in nature. The waste produced from electronic devices in known as e-waste. This waste is non-degradable and yet there are not proper methods available to handle this kind of waste. This kind of waste is becoming a serious problem in developed and developing countries.
(b) Ozone layer depletion:- Some organic compounds are present in the atmosphere that are responsible for ozone depletion. Such as CH4, CO2, NO2, CFCL2
etc. Those compounds use oxygen from ozone and result in its depletion. The major role is played by chlorofluorocarbons (CFC). They have shelf life of about 100years in the atmosphere. It was manly produced by refrigerators. In some areas, the sunlight reacts more with CFC and other organic compounds that resulted in removal of ozone form that area and the weakest ozone layer is known as ozone hole. This leads to allowance to UV rays to enter earth’s atmosphere.(c) Red Data Book:- IUCN (International Union of conservation of Nature and Nature Resources). Which is now called world conservation union, maintains a red data book or red list which is a catalogue of taxa facing risk of extinction. Red list has following category of species:-
1. Extinct:- That have been completely eliminated from earth example:- Dodo.
2. Extinct in wild:- Taxa that is extinct from its natural habital.
3. Critically endangered:- The taxon is facing high risk of extinction in wild and become extinct in immediate future.
4. Endangered:- it is facing high risk of extinction in wild in near future.
5. Vulnerable:- Presently the population is sufficient but due to some factors it is facing risk of extinction in mid-term future.
6. Lower risk:- They are threatened species which have lower risk of extinction and require small attention.
7. Data deficient:- A taxon is data deficient when no adequate information is available regarding direct or indirect assessment of its risk of extinction.