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BIOLOGY

2024

BIOLOGY OLD QUESTION PAPER SOLVED

Part – Ⅰ (Botany)

1. Name the Bacterium used in pesticides?

Ans: Bacillus thuringiensis.

2. Who first coined the term ‘mutation’?

Ans: Hugo de Vries.

3. Give an example of adaptive radiation.

Ans. Darwin’s finches. 

4. What is gene therapy?

Ans. Gene therapy is a collection of methods  that allow correction of a gene defect that has been diagnosed in an embryo. 

5. Answer the following:

(a) Write the biotic component of an ecosystem.

Ans. Animals, plants, Fungi and Bacteria.

(b) Name one homologous and one analogous organ of plant.

Ans. Bougainvillaea is homologous, sweet potato is analogous.

(c) Define fermentation. Name one microorganism used in industrial fermentation.

Ans. The process in which Detritivores break down detritus into smaller particles. Saccharomyces cerevisiae is used in industrial fermentation.

(d) Mention the different kinds of pollination.

Ans. Pollination can be three types:

(i) Autogamy.

(ii) Geitonogamy. 

(iii) Xenogamy.

6. Write short notes on: (any two)

(a) Embryosac.

Ans. The embryosac is a thin walled sac within the ovule of a flowering plant that contains the egg nucleus and other nuclei.An embryo sac is said to form when the haploid megaspore nucleus divides. It possesses two haploid nucleus and six haploid cells which do not have cell walls. The polar nuclei combine, generation a diploid secondary nucleus develops into an endosperm.

(b) Antibiotic. 

Ans. Antibiotics produced by the microbes are regarded as one of the most significant discoveries of the twentieth century and have greatly contributed toward the welfare of the human society. Anti is a Greek word that means against life. Whareas with reference to human Beings they are pro life and not against. Antibiotics are chemicals substances, which are produced by some microbes and can kill or retard the growth of other microbes.

(c) Ecological Succession. 

Ans. The process of change in the species composition of a biological community overtime it involves the replacement of one community by another in the same area resulting in changes to the ecosystem’s structure and function. There are two  main types of ecological succession.

(i) Primary Successession. 

(ii) Secondary Successession.

7. Write the scientific name with the utility of the following plants:

(a) Neem.

Ans. Azadirachta indica.

(b) Rauwolfia. 

Ans. Rauwolfia serpentina.

(c) Cinchona.

Ans. Cinchona officinalis.

(d) Sal.

Ans. Shorea robusta.

8. How is genetically engineered insulin produced?

Ans. Genetically engineered insulin produced by the human inserting the human insulin gene into plasmid into bacteria, and putting the recombinant bacteria in fermentation tanks.

Or

Describe the various types of ecological pyramids.

Ans. Their are three types of ecological pyramids:

(a) Pyramid of number: pyramid of number in a grassland ecosystem. Only three top – carnivores  are supported in an ecosystem based on production of nearly 6 millions  plants.

(b) Pyramid of biomass: pyramid of biomass shows a sharp decrease in biomass at higher trophic levels.

(c) Pyramids of energy: pyramid of biomass small standing crop  of phytoplankton supports large standing crop of zooplankton. 

9. Draw and describe the different parts of a complete flower.

Ans.

The different parts of a complete flowers are as follow:

(i) Sepals: These are the small, leaf like parts growing at the base of the petals. They form the outermost whorl of the flower.

(ii) Petals: This layer lies just above the sepal layer. They are often bright in colour as their main function is to attract pollinators such as insects, butterflies etc  to the flowers .

(iii) Stamens: These are the male parts of a flowers. Many stamens are collectively known as the androecium.

(iv) Filament: The part that is long and slender and attached the anther to the flower.

(v) Anthers: It is the head of the stamen and is responsible for producing the pollen which is transferred to the pistil or female parts of the same or another flower to bring about fertilization.

(vi) Pistil: This forms the female parts of a flower. A collection of pistils is called the gynoecium.

Female reproductive organs consisting of: 

(a) Stigma: The sticky surface at the top of the pistil that catches pollen.

(b) Style: The narrow tube that connects the stigma to the ovary.

(c) Ovary: The base of the pistil that contains ovules (eggs) where fertilization occurs.

Or

Explain the Hardy-Weinberg principle.

Ans. Hardy-Weinberg principle stated it using algebraic equations. This principle says that allele frequencies in a population are stable and is constant from generation to generation. The gene pool (total genes and their alleles in a population) remains a constant. This is called genetic equilibrium. Sum total of all the allelic frequencies is 1. Individual frequencies, for example, can be named p, q, etc. In a diploid, p and q represent the frequency of allele A and allele a. The frequency of AA individuals in a population is simply p². This is simply stated in another ways, i.e., the probability that an allele A with a frequency of p appear on both the chromosomes of a diploid individual is simply the product of the probabilities, i.e., p². Similarly of aa is q², of Aa 2pq. Hence, p² + 2pq + q² = 1. This is a binomial expansion of (p + q)². When frequency measured differs from expected values, the difference (direction) indicates the extent of evolutionary change. Disturbance in genetic equilibrium, or Hardy- Weinberg equilibrium, i.e., change of frequency of alleles in a population would then be interpreted as resulting in evolution. 

10. Write an account on biotechnological application in agriculture.

Ans. Biotechnology has revolutionized agriculture, enabling farmers to produce more efficiently, sustainably, and safely.

Here are some key biotechnological applications in agriculture:

(i) Genetic engineering: Techniques to alter the chemistry of genetic material (DNA and RNA) to introduce these into host organisms and thus change the phenotype of the host organism.

(ii) Bioprocess engineering: Maintenance of sterile (microbial contamination-free) ambience in chemical engineering processes to enable growth of only the desired microbe/eukaryotic cell in large quantities for the manufacture of biotechnological products like antibiotics, vaccines, enzymes, etc.

Or

Write briefly on modern synthetic theory of evolution.

Ans: The Modern Synthetic Theory of Evolution, also known as the Neo-Darwinian theory, is a widely accepted theory that explains how evolution occurs. It combines Darwinian evolution with Mendelian genetics to describe how genetic changes in a population lead to the formation of new species.

The theory is based on several concepts, including:

(i) Genetic variability: Genetic variations in a population play a role in evolution. 

(ii) Natural selection: Natural selection is a major factor in evolution. 

(iii) Reproductive and geographical isolation: Populations with different genotypes must be isolated so that differences can accumulate and form new species. 

(iv) Gene pool and gene frequency: The theory describes the gene pool and gene frequency of a population

11. Describe the carbon cycle in ecosystem with diagram.

Ans. Carbon Cycle is a biogeochemical cycle where various carbon compounds are interchanged among the various layers of the earth, namely, the biosphere, geosphere, pedosphere, hydrosphere and atmosphere.Carbon Cycle is an important aspect of the survival of all life on earth. From an environmental perspective, carbon provides insulation by trapping the sun’s heat. From a biological perspective, carbon is the building block of life and forms stable bonds with other elements necessary for life.

 Some steps of the carbon cycle are as follow: 

(i) Photosynthesis: Plants absorb carbon dioxide from the atmosphere and use it to produce carbohydrates and oxygen.

(ii) Consumption: Animals eat plants and accumulate carbon in their bodies. 

(iii) Decomposition: When plants and animals die, carbon is released back into the atmosphere. 

(iv) Fossil fuels: Some carbon becomes fossil fuels when plants are buried. 

(v) Combustion: When fossil fuels are burned for human activities, carbon is released into the atmosphere. 

(vi) Respiration: During respiration, organisms break down glucose to produce energy and carbon dioxide. 

Or

Describe the process of tissue culture.

Ans. Tissue culture is a process that involves exposing plant tissue to a specific regimen of nutrients, hormones, and light under sterile, in vitro conditions to produce many new plants, each a clone of the original mother plant, over a very short period of time.

There are some steps of tissue culture:

(i) Initiation Phase: The tissue is initiated in the culture at this time. The tissue of interest is acquired, introduced, and sterilized to avoid contamination.

(ii) Multiplication Phase: The sterile explant is placed in a medium containing growth regulators and required nutrients. They are responsible for cell division and multiplication to produce an undifferentiated mass of cells known as a callus.

(iii) Root Formation: At this stage, to start the root development process, hormones are given. The roots begin to grow, and plantlets are formed.

(iv) Shoot Formation: Plant hormones are administered to promote the formation of shoots, and growth is monitored for a week.

(v) Acclimatization: When plants begin to grow, they are moved to a greenhouse where they can grow in a controlled environment. Finally, they are delivered to the nurseries.

Part – ⅠⅠ ( Zoology)

Fill in the blanks: 

(a) The acrosomal vesicle of mature sperm contains __________.

Ans. Hydrolytic enzymes.

(b)  _____________ was known as father of genetics.

Ans. Gregor Mendel.

(c) Transgenic cow milk contains _______________ protein.

Ans. Alpha – lactalbumin.

(d) The disease transmitted through sexual intercourse is _______________.

Ans. Syphilis.

2. Answer any two:

(a) What is ovulation?

 Ans. The Graafian follicle now ruptures to release the secondary oocyte (ovum) from the ovary by the process called ovulation.

(b) Name one contagious disease.

Ans. Common cold.

(c) What is human genome?

Ans. Human genome is said to have approximately 3 x 10⁹ bp, and if the cost of sequencing required is US $ 3 per bp (the estimated cost in the beginning), the total estimated cost of the project would be approximately 9 billion US dollars.

(d) Name the host plant of Muga silkworm.

Ans. The host plants of the muga silkworm are the som (Persea bombycina) and soalu (Litsea monopetala) trees:

3. Answer any four:

(a) Write the different stages of fertilization.

Ans. The different stages of fertilization are:

(i) Fusion of Gametes.

(ii) Penetration of the Zone pellucida.

(iii) Fusion of the sperm and Egg Nuclei.

(b) What is meant by incomplete dominance?

Ans. Incomplete dominance is a phenomenon in genetics where one allele does not completely dominate the expression of the other allele. Instead, the effect of the two alleles is blended, resulting in a new trait that is a combination of the two parental traits.

(c) Write the name of the enzymes in DNA replication.

Ans. The Name of the enzymes in DNA replication are: 

DNA helicase, RNA primase, DNA polymerase, and DNA ligase.

(d) Mention the various types of cancer.

Ans. The various types of Cancer are:

Carcinoma, sarcoma, leukemia, and lymphoma.

(e) Name two biosphere reserves of North-East Region of India. 

Ans. Dibru-Saikhowa, Assam and Nokrek, Meghalaya.

 4. Write the differences between:

(a) Linkage and recombination.

Ans. 

(b) Nucleotide and nucleoside.

Ans.

(c) Vaccination and Immunisation.

Ans.

(d) Addiction and Dependence.

Ans.

5. Draw a labelled diagram of T.S. of testis.

Ans.

Or

Draw a labelled diagram of transmission process in bacterial cell.

Ans.

6. What is genetic diversity? Write its difference from ecological diversity.

Ans. The range of distinct inherited qualities within a species is genetic diversity.

The different forms of ecological diversity:

(i) Species Diversity: Species diversity refers to the variety of different species present in an ecosystem. This includes the number of species, as well as the relative abundance of each species.

(ii) Genetic diversity: A single species might show high diversity at the genetic level over its distributional range. The genetic variation 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.

(iii) Ecological diversity: At the ecosystem level, India, for instance, with its deserts, rain forests, mangroves, coral reefs, wetlands, estuaries, and alpine meadows has a greater ecosystem diversity than a Scandinavian country like Norway.

(iv) Functional Diversity: Functional diversity refers to the variety of different roles or functions that species play in an ecosystem. This includes different types of herbivores, carnivores, decomposers, and primary producers.

(v) Phylogenetic Diversity: Phylogenetic diversity refers to the variety of different evolutionary histories present in a group of organisms. This includes the number of different taxonomic groups, as well as the relationships between them.

Or

Define mutation. Write about the differences between deletion and duplication.

Ans. Mutation is a phenomenon which results in alteration of DNA sequences and consequently results in changes in the genotype and the phenotype of an organism.

7. Write the diseases of silkworm.

Ans. Pebrine is the most serious disease of muga silkworm caused by a protozoan of Nosema sp. It is unique in being transmitted to offspring by transovarial/ transovum means from other moths. If infection is primary, more than 50% larvae die before 3rd moult and rarely any larva goes for spinning.

8. How did Griffith prove that DNA is the genetic material?

Ans: In 1928 by Frederick Griffith was the first experiment suggesting that bacteria are capable  of transferring genetic information through the process known as transformation.

Griffith was studying the possibility of creating a vaccine for pneumonia. He used two strain of pneumococcus bacteria which infect mice- a type III – S (Smooth) and type II- R (Rough) strain.

In this experiment, Bacteria from type III-S Strain were killed by heat and their  remains were added to type  II- R Strain bacteria while neither alone harmed the mice , the combination  was able to kill the host .Griffith was also able to isolate both live II-R and live III-S Strain of pneumococcus  from the blood of these  dead mice .Giffith concluded that the type II-R has been transforming  into the lethal III-S strain by a transforming principle that was somehow part of the dead III-S strain bacteria. He has no idea of that transforming agent.

Or

Describe the various population growth factors.

Ans. (i) Natality – Also known as birth rate, it is the number of people born during a given period. An increased birth rate inturn causes the number of people in a population to grow. 

(ii) Mortality – The term mortality refers to the number of deaths in the population during a given time frame. It causes a decrease in the number of people in the population.  

(iii) Immigration – Immigration refers to the number of individuals of the same species, moving from one area to another during a particular period, causing the population to increase or grow.

9. Describe the reproductive health problems and strategies.

Ans. Some common  reproductive health problem include:

(i) SEXUALLY TRANSMITTED INFECTIONS (STIS): Infections or diseases which are transmitted through sexual intercourse are collectively called sexually transmitted infections (STI) or venereal diseases (VD) or reproductive tract infections (RTI).

(ii) MEDICAL TERMINATION OF PREGNANCY (MTP): Intentional or voluntary termination of pregnancy before full term is called medical termination of pregnancy (MTP) or induced abortion. Nearly 45 to 50 million MTPs are performed in a year all over the world which accounts to 1/5th of the total number of conceived pregnancies in a year.

(iii) INFERTILITY: A discussion on reproductive health is incomplete without a mention of infertility. A large number of couples all over the world including India are infertile, i.e., they are unable to produce children in spite of unprotected sexual co -habitation.                                        

Or

Describe the salient features of human genome.

Ans: (i) The human genome contains 3164.7 million bp.

(ii) The average gene consists of 3000 bases, but sizes vary greatly, with the largest known human gene being dystrophin at 2.4 million bases.

(iii) The total number of genes is estimated at 30,000–much lower than previous estimates of 80,000 to 1,40,000 genes. Almost all (99.9 per cent) nucleotide bases are exactly the same in all people.

 (iv) The functions are unknown for over 50 per cent of the discovered genes.

 (v) Less than 2 per cent of the genome codes for proteins.

 (vi) Repeated sequences make up very large portion of the human genome.