Class 12 biology 1 mark questions

2024 में आने वाले Class 12 biology 1 mark questions इस प्रकार हैं

2024 में आने वाले Class 12 biology 1 mark questions part-1

(a) TAC           (b) UAC

(c) UTC           (d) AUG

• (b)
• The transcribed mRNA of a segment of DNA with the codons GAT CAT TAT is

(a) CUA GUA AUA        (b) CUA GUA UAU

(c) CAU GUA AUA        (d) CUA GAU AUA

• (a)
• The complementary strand of DNA synthesised on a template of DNA with the codons TAG CAT. ACT is    (a) ATCGTA TGA  (b) AUCGATTGA  (c) ATGGUATGA  (d) ATCGTA TCA
• (a)
• What is the function of amino-acyl-tRNA synthetase?
• The enzyme helps in combining amino acid to its particular acid and is specific for amino acid.
• A technique used in making copies of a specific segment of DNA involves:

(a) ligase chain reaction                             (b) transcription

(c) polymerase chain reaction                    (d) translation

• (c)
• What forms the backbone of a polynucleotide strand of a nucleic acid?
• The backbone of each polynucleotide chain is made of alternate sugar-phosphate groups.
• Who proposed the central dogma of molecular biology?
• The concept of central dogma was proposed by Francis Crick in 1958.
• Write the concept of central dogma.
• The concept of central dogma proposed unidirectional flow of information from DNA to RNA and then to protein.
• What is the distance between two base pairs in DNA?
• The average distance between two adjacent base pairs in DNA is about 0.34 nm (3.4 A).
• Which one is removed during splicing-introns or exons?
• Splicing is removal of introns and fusion of exons to form functional RNAs
• How many base pairs are present in one full turn of DNA helix?
• There are roughly 10 base pairs in each turn.
• Name the enzyme that joins the short pieces in the lagging strands during synthesis of DNA.
• The enzyme DNA ligase joins the sort pieces (Okazaki Fragments) in the lagging strands during DNA synthesis
• Who first identified DNA and what was it named?
• Friedrich Meischer named it nuclein.
• What is the term used for the regions of a gene which become part of mRNA and code for the different regions of proteins.
• Exon.
• How are the two strands in a DNA molecule held together?
• The two strands are held together by hydrogen bonds between their bases.
• Define a codon.
• Three adjacent bases constitute a codon which specifies the placement of one amino acid in a polypeptide.
• What are introns?
• Introns are the segments of mRNA which do not take part in the synthesis of proteins.
• Name one organism where RNA is the genetic material.
• Tobacco Mosaic Virus or TMV.
• What is origin of replication?
• DNA replication begins at a particular spot called origin of replication.
• When does DNA replicate in the cell cycle of eukaryotes?
• DNA replication occurs during S-phase of cell cycle.
• Define transcription.
• The process of copying genetic information from sense strand of the DNA into RNA is called transcription.
• What is meant by hnRNA?
• Primary transcript is often larger than the functional RNAs, which is called heterogeneous or hnRNA especially in case of mRNA.
• Who first suggested that codons are triplets?
• George Gamow first suggested that codons are triplet.
• What is meant by unambiguous Lode?
• One codon specifies only one amino acid and not any other.
• Define translation.
• Translation is the process of polymerisation of amino acids to form a polypeptide.
• Describe an anticodon?
• The anticodons present on the tRNA are made up of three nitrogen bases for recognising and attaching to the codon of mRNA.
• Who proposed the operon concept?
• Jacob and Monad (1961).
• Name the inducer of lac-operon concept?
• Lactose.
• What does the gene z code for, in the lactose operon?
• The gene z codes for beta-galactosidase (p-gal), which is primarily responsible for the hydrolysis of the lactose.
• When was the Human Genome Project launched and when was it completed?
• Human Genome Project is a mega project started in 1990 and completed in 2003.
• Name the chromosome that has
  • The most/maximum number of genes
  • The least number of genes.
• Chromosome I has the maximum number of genes (2968).
• Y -chromosome has the least number of genes (231).
• Who discover the technique of DNA finger-print?
• Sir Alec Jeffrey discovered the technique of DNA fingerprinting.
• Define DNA polymorphism.
• If a variant at a locus (in the satellite DNA of human genome) is present with a frequency of more than 0.01 populations, it is called DNA polymorphism.
• What is a probe in DNA-finger printing?
• DNA probes contain repeated sequences of bases complementary to those on VNTRs and are made radioactive by labeling with radioactive isotopes.
• Define DNA fingerprinting.
• DNA fingerprinting is a modern technique of identifying individuals by comparing nucleotide sequences of their DNAs.
• Name the enzymes which cut the DNA molecules into fragments with sticky ends.
• Restriction endonucleases
• What are Variable Number of Tandem Repeats or VNTRs?
• These are short nucleotide repeats in the DNA that vary in number from person to person, but are inherited.
• Who for the first time experimentally demonstrated bacterial transformation? Which bacterium was used?
• Transformation was first studied by S.f. Griffith (1928) in Streptococcus pneumoniae.
• How is protein synthesis initiated in a cell?
• During initiation of protein synthesis, the m-RNA at its 5′- end binds to the small sub-unit of ribosome.
• Who experimentally proved that DNA replication is semi-conservative?
• Matthew Meselson and Franklin Stahl.
• Mention the components of a transcription unit.
• It has three components (i) a promoter, (ii) the structural gene and (iii) a terminator.
• Name the factor present in DNA which is required for termination of transcription.
• Termination Factor called Rho (p) factor
• What are retroviruses?
• Group of viruses containing RNA as hereditary material are known as retroviruses.
• Define transduction.
• The transfer of genetic material from one bacterium to another through bacteriophage is called transduction.
• What do you understand by semi-conservative replication of DNA?
• It is a type of DNA replication in which one strand of the daughter duplex is derived from the parent while the other strand is formed anew
• Define nucleoside and nucleotide.
• A sugar molecule with the nitrogenous base forms a nucleoside. A nucleoside with a phosphate group forms a nucleotide.
• Name the amino acid first coded in protein synthesis
• Methionine is the first amino acid coded in protein synthesis.
• What are the termination codon on mRNA?
• UAA, UAG and UGA are the termination codon on mRNA.
• Which enzyme is responsible for the formation of peptide bond during the protein synthesis?
• The peptide bond formation is catalysed by the enzyme peptidyl transferase.
• Name the major enzyme of DNA replication
• Phosphorylase, primase, DNA polymerase, DNA ligase.
• Define genetic code.
• The relationship between the sequence of amino acids in a polypeptide and nucleotide sequence of DNA or mRNA is called genetic code.
• What is a nucleoid?
• In prokaryotes, the DNA is supercoiled to form a compact mass of DNA called as nucleoid.
• What is the function of a regulator gene in lac-operon?
• In lac operon, the regulator gene called as i-gene produces an inhibitor or repressor which binds to operator gene and stop its working.
• How do the tRNA molecules appear in
  • two dimensional and
  • three dimensional views?
• (1) clover like form
• (2) L-shaped form
• Name the amino acid residues of his tones involved in eukaryotic DNA packing.
• Lysine and Arginine.
• What do you understand by sense strand?
• The DNA strand which functions as template for RNA synthesis is known as sense strand or template strand.
• State anyone reason to explain why RNA viruses mutate and evolve faster than other viruses.
• RNA being unstable mutate at a faster rate. 2′ -OH group present at every nucleotide is a reactive group, so it is vary labile and more catalytic and hence, reactive.
• Mention anyone major source of variation in a sexually reproduced offspring.
• Mutation.
• In which form/ forms did Urey-Miller supply energy in their experiment.
• The energy was in the form of electric discharges from electrodes.
• Who provided experimental support for Oparin-Haldane hypothesis.
• Stanley Miller and Urey.
• Which statement is correct regarding Biston beiularia, a species of moth found in England, during the late 19th century?
• The black colouration of the moth was caused by pollution from burning coal.
•  Black moths were covered with soot from coal burning factories.
•  These moths were killed by devastating fungus Phytophthora.
• An occasional mutation caused black moths to be born.
• (d).
• Name the first probable compound molecules on earth
• Water, Ammonia.
• Who proposed the most accepted theory of the origin of universe Big – Bang Theory?
• Abbe Lemaitre.
• Which theory is also referred as chemical theory or naturalistic theory?
• Oparin Haldane theory.
• Give the age of the earliest free living eukaryotic cell like organisms.
• 1.5 billion years.
• What are homologous organs?
• The organs which have the same internal structure but are different in functions are
  called homologous organs
• Give an example of homologous organs found in plant.
• Thorn of Bougainvillea and tendril of Cucurbita.
• What is molecular homology?
• Homology seen amongst the molecules of organisms is called molecular homology.
• State Haekel’s biogenetic law.
• It states that Ontogeny repeats Phylogeny.
• What is adaptive radiation?
• Development of different functional structures from a common ancestral form is called adaptive radiation.
• Give an example of convergent evolution.
• Australian marsupials and placental mammals show convergent evolution e.g., Placental wolf and Tasmanian wolf marsupial
• What do you mean by parallel evolution?
• When convergent evolution is found in closely related species, it is called parallel evolution.
• What are the two basic points in Darwin’s theory of evolution?
• Branching descent and natural selection are the two basic points in Darwinian Theory of evolution.
• Name the theory of evolution put forward by August Weismann.
• Theory of Continuity of Germplasm.
• In what way mutation theory of Hugo de Varies differs from Darwin’s theory.
• According to Hugo de Vries, new species are not formed by continuous variations but by sudden appearance of variations which he named as mutations.
• What was the plant on which Hugo de Vries conducted his experiments?
• Oenoihera lamarckiana (Evening Primrose).
• Which principle defines the genetic structure of a non-evolving population.
• Hardy – Weinberg Equilibrium Principle.
• Origin of vertebrates took place in which period and in which form.
• Ordovician period in the form of ostracoderms (jaw less vertebrates related to cyclostornes).
• Name the three fossils included in Homo erectus.
• Java Ape man, Peking Man and Heidelberg man.
• Which prehistoric man was referred as the tool maker or handy man.
• Homo habilis.
• Which true man is considered to be more intelligent than the modem man and why?
• Cro- Magnon man, because its cranial capacity was about 1650 cc.
• Which among the three types of natural selection is the rarest?
• Disruptive selection.
• What is known as discontinuous distribution?
• Sometimes closely similar species exist at widely separated places without any representative in intervening territory. This is called discontinuous distribution.
• Name the scientists who disproved the theory of spontaneous generation of life?
• Spallanzani, Redi and Pasteur.
• Name the scientists who experimentally confirmed the Oparin-Haldane theory of the origin of life.
• Stanley Miller and Harold Urey.
• In what form forms had Urey and Miller supplied energy in their experiment?
• Electric sparks and heat from electric heater.
• Who was the first scientist to object ‘theory of abiogenesis’?
• Francisco Redi.
• What is the probable period of origin of cyanobacteria?
• About 3.3 to 3.5 billion years ago.
• Name the possible sources of energy in most accept theory of origin of life.
• UV radiations, electric energy produced during lightening, heat of the earth.
• Which gas was sealed in the spark chamber in famous Miller and Urey simulation experiment?
• Mixture of methane (CH₄), Ammonia (NH₃), Hydrogen (H₂) gas and water (H₂0) vapours.
• Who obtained proteinoid microspheres by heating a mixture of dry amino acids to 130 -I80^aC and later cooling them in water?
• Sydney Fox (1950).
• Give two examples of connecting links.
• Lungfish, egg-laying mammals.
• Name two vestigial organs of human body.
• Nictitating membrane, vermiform appendix
• Mention one temporary embryonic structure of no use.
• Teeth in bird embryo.
• What is Archaeopteryx? What is its significance in evolution?
• It is regarded as a connecting link between reptiles and birds.
• Name the era in the geological time scale when life had not yet originated on earth.
• Early Archeozoic.
• In which era of geological time scale mammals dominated the scene?
• Miocene epoch of Cenozoic era.
• Name the theory of evolution proposed by Lamarck.
• Inheritance of acquired characters.
• Evolution is a discontinuous process. Is it correct?
• Yes.
• Cite one example of natural mutation producing a new species.
• Ancon (short-legged) sheep.
• What is the significance of the Lederberg experiment?
• It demonstrates that preexisting gene mutation is the basis of adaptation.
• It demonstrates that preexisting gene mutation is the basis of adaptation.
• Dryopithecus.
• Where have the fossils of Ramapithecus found?
• In the Shivalik hills of India.
• Name the extinct representative of modern man.
• Cro-Magnon man.
• Name any two vertebrate body parts that are homologous to human forelimbs.
• Forelimbs of horse / cow / dog / cat
  Wings of bird / bat.
• Flippers of dolphins / whale / seal
• What causes speciation according to Hugo deVries?
• Mutation (s)/large (heritable) differences arising suddenly in a population/Saltation (single step large mutation).
• Expand the term LAB.
• Lactic acid bacteria.
• What is the role of LAB in our stomach?
• In our stomach LAB play a very beneficial role in checkirig disease – causing microbes.
• Write the scientific name of baker’s yeast.
• Saccharomyces cerevisiae
• What is toddy?
• Toddy a traditional south Indian drinks containing 6% alcohol and is produced by fermenting sap from palm.
• What are the causes of large holes in ‘Swiss cheese’?
• The large holes in Swiss cheese are due to production of a large amount of CO₂ by the bacterium Propionibacterium sharmanil.
• What are fermentors?
• Production of industrial products requires growing microbes in very large vessels called ferrnentors.
• Name the microbes used for fermenting malted cereals and fruit juices.
• Saccharomyces cerevisiae.
• What is meant by antibiotic?
• An antibiotic is a substance produced by a microorganism which inhibits the growth and metabolic activity of pathogenic organisms without harming the host.
• Name the first antibiotic to be discovered. Who discovered it?
• Penicillin. It was discovered by Alexander Fleming.
• Name the scientists who established the full potential of penicillin as an antibiotic.
• Earnst Chain and Howard Florey.
• How is acetic acid prepared with the help of microbes?
• It is prepared from fermented alcohols with the help of acetic acid bacteria Acetobacter aceti.
• What is the medical use of cyclosporin A?
• It is used as an immunosuppressive agent in organ – transplant patients.
• How does statin reduce the blood cholesterol level?
• It acts by competitively inhibiting the enzyme responsible for synthesis of cholesterol.
• Define sewage.
• Municipal waste water with large amount of human excreta and other organic wastes is called sewage.
• State one difference between primary and secondary treatment.
• Primary treatment involves the removal of large sized floating and suspended solids by physical methods, while secondary treatment involves decomposition of organic wastes by microbial actions.
• Name the physical processes employed in the primary treatment of sewage.
• Filtration and sedimentation
• What are Flocs?
• Masses of bacteria associated with fungal filaments to form mesh like structures are called flocs.
• What is activated sludge?
• After the reduction of BOD of the sewage the effluent is passed into a settling tank where the bacterial floes are allowed to sediment. This sediment is called activated sludge.
• Name the gas produced in an anaerobic sludge digesters during secondary treatment of        sewage.
• Methane, hydrogen sulphide and carbon dioxide.
• What is the function of methanogens in the rumen of cattle?
• In rumen, the methanogens help in the breakdown of cellulose and play an important role in the nutrition of cattle.             
• Name the gaseous composition of biogas.
• Biogas is made up of methane (50-70%) carbondioxide (30-40%) with traces of hydrogen sulphide and hydrogen.
• Who developed the technology of biogas production in India?
• The technology of biogas production was developed in India by Indian Agricultural Research Institute (lARI) and Khadi Village Industries Commission (KVIC).
• What is meant by biocontrol?
• The natural method of pest and pathogen control involving use of viruses, bacteria and other insects is called biocontrol or biological control.
• Name one fungus which is being developed as a biocontrol.
• Trichoderma species.
• Expand the term
              (i) IARI (ii) IPM
• (i) Indian Agricultural Research Institute, (ii) Integrated Pest Management.
• Name the sources of biofertilisers.
• Bacteria, cyanobacteria (blue-green algae) and mycorrhizal fungi.
• Name the bacterium that acts as a biofertilisers in symbiotic association with legumes.
• Rhizobium.
• Name few cyanobacteria which can fix atmospheric nitrogen.
• Anabaena, Nostoc, Oscillatoria, etc.
• Name any two free-living nitrogen fixing bacteria.
• Azotobacter, Beijerinckia.
• What is Integrated Pest Management?
• Integrated Pest Management is an important step taken by Government of India which involves the harmonious application of various ‘Cultural controls’ to ensure minimum environmental pollution and proper maintenance of ecological balance.
• Name the first organic acid produced by microbial fermentation.
• Lactic acid.
• Expand TPA. Give its importance.
• Tissue Plasminogen Activator. It is an enzyme obtained from the cultures of some haemolytic streptococci. It has fibrinolytic effect. Therefore, it helps in clearing blood clots inside the blood vessels through dissolution of intravascular fibrin.
• State the use of :

(i) Trichoderma with respect to organ transplant, and

(ii) Nucleopolyhedrovirus with respect to pest management.

• (i)Trichoderma-Biocontrol agent of several plant pathogens produces      Cyclosporin A, which is used as an immuno-suppressive agent in organ transplanted patients.
• (ii) Nucleo polyhedrovirus-Narrow spectrum insecticide.          
• Bacteria that convert milk into curd play two other beneficial roles. What are they?
• Increase in nutritional quality (vit. B₁₂); check disease causing microbes in the stomach.
• What are biofertilisers? Name the two elements which are made available by them?
• Biofertilisers are those micro-organisms, which are added to soil to increase its fertility. The elements added by them are nitrogen and phosphorus.
• What is mycorrhiza? How do they help as biofertilisers?
• Mycorrhiza is an association between the roots of a higher plant with a fungus. These fungi solubilize phosphorus and produce growth promoting substances. They also protect the plant from soil pathogens.
• What is BOD? What does it means if a water sample has more BOD?
• Biochemical oxygen demand (BOD) represents the amount of dissolved oxygen that would be consumed to broken down all the organic matter in one litre of water by microorganisms.
• More value of BOD means the water sample is polluted by organic matter.
• What is the function of aeration tank-in the treatment of sewage?
• Aeration tank is meant for agitating the liquid effluent from the primary settling tank, where the air is allowed to pass through agitating mixture to make it aerobic.
• Mention the functions of LAB that are useful to man
• Lactic acid bacteria growing in milk converts it into curd. LAB converts lactose sugar of milk into lactic acid, which causes coagulation of milk protein caesin.
• It also increases the nutritional quality of curd by increasmg the content of vitamin B₁₂. In our stomach, the LAB play very beneficial rule in checking disease-causing microbes.
• What is the use of Baker’s yeast in the production of bread?
• Saccharomyces cerevisiae (Baker’s yeast) causes alcoholic fermentation of sugars of wheat flour and produces ethanol and CO₂, This raises the dough. The raised dough when baked is porous and soft as CO₂ and ethanol evaporates.
• Name any two varieties of cheese and mention the name of the microbes used.
• Swiss cheese – Propionibacterium sharmanii.
• Roquefort cheese – Peniciluumroqueiorti.
• Name two alcoholic drinks produced in each of the following ways:

        (i) Without distillation       (ii) With distillation

• (i) Without distillation :- wine and beer
• (ii)With distillation :- Whisky and Brandy
• What are bioactive molecules? Give two examples.
• Bioactive molecules are those molecules, which are functional in living systems organ or can interact with their components.
• Examples: Bioactive molecule obtained from microbes are statin, cyclosporin A  etc,.
• What is the microbial source of streptokinase? What is the medical use of it?
• The enzyme streptokinase is produced by the bacterium Streptococcus.
• It is modified by genetic engineering and used as a ‘Clot-buster’ for removing clots from blood vessels especially in people who have undergone myocar~”tntraction leading to heart attack.
• Name the microbial sources of bioactive molecules cyclosporin A and Statin
• (i) Cyclosporin A – . Trichoderma polysporum                                       .

                  (ii) Statin         –    Monascus purpureus.

• Give the scientific name of the fungus that produces critic acid. Mention its commercial use
• Citric acid is added in dyeing, engraving, medicines flavorings and preservation of food and citric acid is produced by aspergillus niger
• (i)Why are bottled fruit juices clear as compared to the home-made ones?

            (ii) Give one important function of lipases.

• (i) This is because the bottled juices are clarified by the use of pectinases and proteases.

                 (ii) Lipases are used in detergent formulations and helpful in removing oily stains from the laundry.

• Differentiate between primary sludge and activated sludge?
• The sediment obtained in settling tank during primary treatment of sewage is called as primary sludge, while those obtained during the secondary or biological treatment is referred as activated sludge.
• What is biogas? Name one methanogenic bacterium.
• Biogas is a methane rich fuel gas produced by anaerobic breakdown or digestion of biomass with the help of methanogenic bacteria.
• Methanogenic bacterium – Methanobacterium.
• What are baculoviruses? Give one example.
• Baculoviruses are pathogens that attack insects and other arthropods. The majority of baculoviruses, used as biological control agents, are in the genus Nucleopolyhedrovirus.
• What is the role of baculoviruses in the Integrated Pest Management (IPM) programme?
• Baculoviruses are ideally suited for species – specific, narrow spectrum insecticidal applications.
• They have no negative impact on plants, mammals, birds or even on non-target insects. This is especially desirable as it aids in the overall IPM programme, where beneficial insects are conserved.
• What are biofertilisers? Name two free living nitrogen fixing bacteria found in the soil
• Biofertilisers are microorganisms, which bring about nutrient enrichment of soil by enhancing the availability of nutrients like nitrogen and phosphorus.
• Azotobacter, Azospirillum.
• Define Biotechnology?
• It is the controlled use of biological agents, such as live organisms or cellular components to produce products and processes useful to men.
• Which enzymes are called molecular scissors?
• Restriction endonucleases.
• Name the enzymes which cut the DNA molecules into fragments with sticky ends.
• Restriction endonucleases
• Name two types of cloning vectors?
• (i) Plasmid vectors and (ii) Bacteriophage vectors.
• What is vector?
• Vector is DNA molecule that can carry a foreign DNA segment and replicates inside the host cell.
• How many types of restriction endonucleases are found?
• Three types namely Type I, Type II and Type III.
• Which type of restriction endonucleases take part in recombinant DNA technology?
• Type II.
• Write another name of genetic engineering.
• Recombinant DNA technology.
• Which was the first enzyme taking part in genetic engineering?
• Restriction endonuclease.
• Which cloning vector was discovered first time?
• Cloning vector pBR322
• Name the method in which foreign DNA is directly introduced into host cell?
• Microinjection.
• Write the full form of PCR?
• Polymerase Chain Reaction.
• What are exonucleases?
• They remove nucleotides from the ends of the DNA.
• Name the enzyme commonly used to dissolve the bacterial cell wall.
• Lysozyme
• What are molecular scissors?      
• These are restriction endonucleases which cut the DNA molecule into fragments with sticky ends.
• What are plasmids?
• Plasmids are extra-chromosomal, self-replicating, usually circular, double stranded DNA molecules found naturally in many bacteria and also in some yeast.
• What do you mean by Ori?
• Ori is the short form of origin of replication. This is the sequence from where replication start
• Which was the first type II restriction endonuclease to be discovered?
• Hind II (From Haemophilus influenzae, strain Rd)
• Name a ‘natural genetic engineer’ of plants.       
• Agrobacterium tumifaciens, a crown gall bacterium is called natural genetic engineer of plants.
• What type of cut ends are formed when both the strands of DNA molecule is cleaved at exactly the same nucleotide position?
• Blunt or flush end.
• What is microinjection?
• Microinjection is the method of introducing recombinant DNA by directly injecting it into the nucleus of an animal cell.
• What is gene gun?
• It is a method of vectorless direct gene transfer in which the plant cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA.
• What is the function of DNA-ligase?
• The enzyme DNA-ligase covalently links the two sticky ends of DNA fragments.
• What are the three basic steps involved in a single PCR amplification cycle.
• The three basic steps are denaturation, annealing and extension (polymerisation)
• Name the polymerase which is generally used in PCR reactions.
• Taq polymerase
• Who invented Polymerase chain Reaction?
• Kary Mullis
• Taq polymerase is isolated from which bacterium.
• It is isolated from a bacterium Thermus aquaticus.
• What are the basic requirements of a PCR reaction?
• DNA template, Primers and Enzyme
• A technique used in making copies of a specific segment of DNA involves

     (i) ligase chain reaction
      (ii) transcription

(iii) polymerase chain reaction

     (iv) translation                                                                                         

• (iii)
• What do cellular oncogenies code for, in normal cells?
• Cellular oncogenes (c-one) when activated by the carinogens cause alteration in the genetic material, which leads to oncogenic transformation of the cells.
• Give the scientific name of the causative germ of elephantiasis.
• Wuchereria bancrofti and W. malayi.
• What is meant by metastasis?
• Cells deteched from malignant tumours reach distant sites through blood and wherever they get lodged in the body they start a new tumour there. This property is called metastasis.
• Diagnosis of typhoid is done by,

(a) ESR     (b) ELISA test (c) Widal test

• (c)
• The pathogen that causes elephantiasis is,
• Wuchereria bancrofti 
•  Treponema palladium
• Entamoeba histolytica
• Ascaris lumbricoides
• (a)
• The pathogen that causes malaria is,
  • female Anopheles
  • female Culex
  • Mycobacterium
  • Plasmodium
• (d)
• Which category of adaptive immunity is provided by vaccination
• Artificial active immunity
• What are interferons
• Interferons are anti-viral proteins released outside by the virus-infected cells, which protects non infected cells from further viral infection.
• Name the type of cells that produce antibodies.
• Antibodies are produced by B-Iymphocytes and plasma cells
• How does saliva act in body defence?
• Bicarbonate ions in salvia neutralise the acids in food.
• What are primary lymphoid organs?
• The primary lymphoid organs are those organs where T lymphocytes and B lymphocytes, mature and acquire their antigen-specific receptors.
• What happens in lymphoid organs with respect to immunity?
• The maturation and proliferation of lymphocytes-takes place in the lymphoid organs
• Name the two major groups of cells required in attaining specific immunity.
• T lymphocytes and B lymphocytes.
• It was diagnosed by a specialist that the immune system of the body of a patient has been suppressed. Name the disease the patient is suffering from and its causative agent
• Acquired Immun Deficiency Syndrome (AIDS) and it is caused by Human Immunodeficiency Virus (HIV), a retrovirus.
• Define disease.
• Any functional or physical change from the normal state that causes discomfort, disability, or impairs the health of a living organism is called a disease
• Name two diseases that spread by droplet infection.
• The two diseases that spread by droplet infection are diptheria and common cold.
• Name two important diseases caused by bacteria.
• Typhoid and Tuberculosis.
• What name is given to the infectious stage of Plasmodium?
• The infective stage of Plasmodium is the sporozoite.
• Mention the main source of infection of typhoid.
• The pathogens enter the small intestine by consumption of food and water contaminated with them.
• Give two examples of diseases caused by protozoans.
• Amoebiasis and Malaria.
• Name the causal organism which causes amoebic dysentery.
• Entamoeba histolytica.
• What is ‘Typhoid Mary’?
• Typhoid Mary was a cook by profession and a typhoid carrier, who continued to spread typhoid for several years through the food she prepared.
• Name the types of barriers which confers innate immunity.
• Physical barriers, physiological barriers, cellular barriers and cytokine barriers.
• Why is the antibody-mediated immunity called humoral immunity?
• Antibody-mediated immunity is also called as humoral immune response because these antibodies are found in the blood.
• Which type of immune response is responsible for the graft rejection?
• Cell-mediated immune response.
• What is passive immunity?
• When ready-made antibodies are directly given to protect the body against foreign agents, it is called passive immunity.
• Define vaccination.
• The process of introduction of vaccine into an individual to provide protection against a disease is called vaccination.
• Which property of the immune system forms the basis of the immunisation and vaccination?
• The principle of immunisation or vaccination is based on the property of ‘memory’ of the immune system.
• Define allergy.
• Allergy is the presensitiveness of a person to some foreign substance when coming in contact with or entering the body.
• Recently chikungunya cases were reported from various parts of the country. Name the vector responsible.     
• Aedes mosquitoes
• Give examples of secondary lymphoid organs.
• Secondary lymphoid organs are lymph nodes, spleen tonsils, Peyer’s patches of the small intestine, appendix and muscosal associated lymphoid tissues
• Give two examples of primary lymphoid organs.
• Bone marrow and thymus.
• Which is the main lymphoid organ of the body?
• Bone marrow is the main lymphoid organ where all blood cells including lymphocytes are produced.
• Write the full from of NACO.
• National AIDS Control Organisation.
• Name the cells of immune system that are affected by HIV.
• Helper T-Iymphocytes and macrophages.
• What is meant by contact inhibition?
• Normal cells of the body show a property called contact inhibition by virtue of which contact with other cells inhibits their uncontrolled growth.
• Name the most common infectious fungal disease.
• Ring worm.
• What is the role of histamine in inflammatory response?
• Histamine is released by lymphocytes, which cause blood vessels to dilate.
• Name the two chemicals released by damaged cells, that help in immunity.
• Histamine and prostaglandins.
• What are antigenic determinants?
• Antigenic determinants are those sites on antigens that are recognised by antibodies and receptors present on B-cells and T -cells.
• Mention the four general methods of treatment of cancer.
• Surgery, radiation therapy, chemotherapy and immunotherapy.
• What is heroin chemically?
• Heroin, commonly called smack is chemically diaetylmorphine.
• Give the scientific name of the plant from which cocaine is obtained.
• Coca alkaloid or cocaine is obtained from coca plant Erythroxylum coca.
• Name some drugs which are normally used as medicines but are often abused.
• Drugs like barbiturates, amphetaminos, benzodiazepines, lysergic acid diethyl amides (LSD).
• Define adolescence.
• Adolescence means both a period and a process during which a child becomes mature in terms of his/her attitudes and beliefs for effective participation in society.
• Why does blood pressure or heart rate increase by tobacco consumption?
• Tobacco contains an alkaloid nicotine, which stimulates adrenal gland to release adrenaline and noradrenaline in blood circulation, both of which raise blood pressure and increase heart beat.
• What do you understand by addiction?
• Addiction is a psychological attachment to certain effects- such as euphoria and a temporary feeling of well-being associated with drugs and alcohol.
• How is oxygen deficiency caused in the body by smoking?
• Smoking increases carbon monoxide (CO) content in blood and reduces the concentration of haembound oxygen. This causes oxygen deficiency in the body
• Name two plants that have hallucinogenic properties.
• Atropa belladona and Datura.
• Name three diseases caused by alcohol.
• Alcohol dementia, Alcoholic myopathy and Alcohol cirrhosis.
• Mention any two measures for prevention and control of alcohol and drug abuse among
  adolescents.
• Avoid undue peer pressure, education and counselling, seeking help from parents and peer, looking at danger signs, seeking professional or medical help. (any two)
• How do neutrophils act as a cellular barrier to pathogens in humans?    
• Phagocytose/kill/destroy microbes.
• Name the two types of cells in which the HIV multiplies after gaining entry into the human body.
• HIV enters – Macrophages
  Helper T lymphocytes
• Given below are some human organs. Identify one primary and one secondary lymphoid organs:        Liver, Thymus, Stomach, Thyroid, Tonsils.         
• Primary lymphoid organ – Thymus
• Secondary lymphoid organ – Tonsils
• Name few drugs which reduce the symptoms of allergy.
• Antihistamine, adrenaline and steroids.
• What causes swelling of the lower limbs in patients suffering from filariasis?     
• Chronic inflammation of lymphatic vessels due to the presence of the worms
• How do B- cells of the immune system respond to antigens?
• B-Iymphocytes or B-cells produced by the bone marrow produce specialised proteins called antibodies and therefore, generate antibody mediated or humoral immunity. The B-cells also give rise to plasma cells (effector B cells), which after exposure to an antigen secrete millions of antibodies daily.
• What harm do cancerous cells cause?      
• Cancer is an abnormal and uncontrolled division of cells, known as cancer cells, that invade and destroy the surrounding tissues. Cancer cells do not respond to control mechanism and do not show contact inhibition, as a result they divide giving rise to masses of cells called tumours. Cells sloughed from malignant tumours reach distant sites through blood, and wherever they get lodged in the body they start a new tumour there. Benign tumours causes little damage to the body
• What are allergens? How do they cause inflammatory response inside the human body?
• The substances that cause allergic reaction are called allergens. They act as a mild antigen and stimulate the formation of IgE antibodies, which bind to mast cells. The allergens then combine with antibody-bound mast cells, which rupture and release histamine and serotonin. It causes marked dilation of all the peripheral blood vessels and the capillaries become highly permeable so that large amounts of fluid leak out from the blood into the tissues. As a result of this, the affected area shows inflammation. This reaction of the body is called inflammatory response and is a part of the internal defence.
• Which kind of immunity, active or passive, is produced by vaccination? Name the disease against which protection is provided by BCG vaccine.
• Active immunity is produced by vaccination.
• The vaccine Bacillus Calmette Guerin (BCG) provides protection against tuberculosis.
• How do B-cells direct humoral immunity?
• B lymphocytes produce antibodies that regulate humoral immunity or antibody-mediated immunity. Antibody formation by B cells is stimulated by helper T cells and inhibited by suppressor T cells. Certain B-Iymphocytes are transformed into plasma cells which produce antibodies at a rapid rate. A small portion of them develops into memory cells which have a long life span and serve to recognise the same antigen when introduced subsequently.                                                             
• Name the cells that produce antibodies. Explain the main function of these compounds.
• Antibodies are produced by B lymphocytes and plasma cells. Antibodies are immunoglobulins (Igs), which are produced in response to antigenic stimulation. They direct the antibody-mediated immunity (= humoral immunity).
• Enumerate any two properties of cancer cells that distinguish them from normal cells.
• Cancer cells divide in an unregulated/ uncontrolled manner as they do not show contact inhibition, which is shown by normal cells. Cancer cells do not have a definite life span. Some of the cancer cells get detached from the main site of origin and travel by blood and lymph to distant sites and form fresh colonies, called metastasis or secondary growth.
• Write the full form of ELISA. Give an example of the clinical application of ELISA test.
• ELISA stands for Enzyme Linked Immunosorbent Assay. HIV infection can be diagnosed by ELISA Test
• Name and explain the type of barrier of innate immunity system, which involves macrophages?
• How do killer T-cells work?
• What is meant by active immunity and passive immunity?
• Define animal husbandry?
• Animal husbandry is the science that deals with feeding breeding, housing, health care of
  common domestic animals for getting maximum benefits.
• Which are the two major practices included in animal husbandry?
• Poultry Farming and Fisheries.
• Define dairying.
• Dairying is the management of animals for milk and its products for human consumption.
• Mention the four essential methods for livestock improvement.
• These are breeding, weeding, feeding and heeding.
• What do you understand by the term poultry.
• The term poultry refers to rearing of birds, which can be raised under domestication for economic
  purpose like chickens, turkeys, ducks, geese, swan, guinea fowls, pea fowls etc.
• What are the two main methods of animal breeding?
• Inbreeding and outbreeding are the two main methods of animal breeding.
• Define outbreeding.
• Outbreeding is the breeding between the unrelated animals which may be between individuals
  of the same breed or between different breeds of different species.
• What are single cell protein (SCP)?
• The cell from microorganisms such as bacteria, yeasts, filamentous algae, treated in various
  ways and used as food, are called single cell protein (SCP).
• Name the two techniques involved in controlled breeding experiments.
• Controlled breeding experiments are carried out by using artificial insemination and multiple ovulation embryo transfer technology (MOET)
• Define apiculture.
• Rearing of honey bees for obtaining honey and bee wax is called apiculture.
• Name the four important species of honey-bees.
• Apis mellifera, A indica, A. dorsata and A. Florea . 
• Define fisheries.
• Fisheries is an industry related to the catching, processing or selling of fish, shellfish or other
  aquatic animals.
• Name some edible marine fishes?
• Hilsa, Sardines, Mackerel and Pomfrets.
• What is meant by plant breeding?
• Plant breeding is the genetic improvement of the crop in order to create desired plant types that are better suited for cultivation which give better yields and are disease resistant.
• Define germplasm collection.
• The entire collection (of plants/seeds) having all the diverse alleles for all genes in a given crop is called germplasm collection.
• Mention the various types of hybridisation involved in plant breeding.
• Hybridisation may involve a single cross or multiple cross. It may be of the following types- intravarietal, intervarietal (= intraspecific) or interspecific and intergeneric.
• Name the two semi-dwarf varieties of wheat introduced into all wheat growing regions of India.
• Sonalika and Kalyan Sona.
• Name the Indian variety of rice patented by an American company.     
• Basmati.
• What are the main factors on which the disease development in a plant depends?
• The three main factors are host genotype, pathogen genotype and environment.
• Mention any two methods used for breeding for disease resistance, apart from the conventional method ofhybridisation.
• Selection among somaclonal variants and genetic engineering.
• Define mutation breeding.
• Use of induced mutations in plant breeding to develop improved varieties is called mutation breeding.
• Give an example where mutation breeding has been successfully carried out for introducing
  disease resistance.
• Resistance to yellow mosaic virus in bhindi (Abelmoschus esculentus) was transferred from a
  wild species Abelmoschus manihotland and resulted in a new variety of A. esculentus called
  Parbhani Kranti.
• What is biofortification?
• Breeding of crops with higher levels of vitamins and minerals or higher protein and healthier fats is called biofortification.
• Define totipotency.
• The capacity to generate a whole plant from any cell or explant is called totipotency.
• What is an inbred line?
• An inbred line is a nearly homozygous line produced by continuous inbreeding in a cross- pollinated crop and is maintained by strict inbreeding.
• During a meristem culture some explants were kept in culture medium containing more of auxins than cytokinins. Which organ of the plant is expected to differentiate from the callus?
• Root
• What is an explant?
• An explant is the plant part excised from a specific location in a plant that is used for initiating a culture.
• Define somaclonal variation .
• The genetic variation found among the plant cells in a culture is called somaclonal variation.
• What is the economic value of Spirulina?
• Food rich in proteins / single cell protein / reduces pollution if grown in large quantities in waste waters.
• List any two economically important products for humans obtained from Apis indica.
• Honey, (Bee) wax.
• Name two diseases caused by fungus in crop plants.
• Brown rust of wheat, red rot of sugarcane.
• What is single cell protein? What is the significance of such a protein?
• Refer (1 Mark Type).

Single cell protein can reduce the pressure on agricultural production systems for the supply of required proteins. As its production is based on industrial effluents it can help to minimise environmental pollution.

• What is inbreeding in plants? What happens to the recessive alleles in this process?
• Inbreeding is mating of individuals that are closely related by ancestry. It is used in developing pure lines or homozygous lines. Self pollination  is a form of inbreeding. Most of the recessive alleles are harmful and therefore, they will express their harmful effects in cross pollinated plants causing in breeding depression
• How is mutation breeding carried out for developing crop varieties?
• Use of induced mutations in plant breeding to develop improved varieties is known as mutation breeding. It is possible to induce mutations artificially through use of chemicals or radiations, and selecting and using the plants that have the desirable character as a source in breeding
• What is interspecific hybridisation? Give one example of a crop in which it is practised and mention one advantage derived from it.          
• Interspecific hybridisation is the process of crossing individuals of two different species to produce a hybrid. Examples of interspecific hybridisation are the development of rice variety ADT – 37 from a cross between Oryza japonica and o. indica.

Advantages: It brings about useful genetic/heritable variations of two or more lines together.

• What is emasculation? Explain its importance in hybridisation.
• What is mutation? List the steps how mutation breeding is carried out in agricultural crops.

• Explain the two essential methods for livestock improvement. (i) Breeding (ii) Weeding.
• Mention the important components of poultry farm management.
• Mention four important objectives of animal breeding.
• Explain artificial insemination method of controlled breeding.
• How are fishes helpful in controlling diseases? Give examples of such fishes.
• What do you understand by the terms’ aquaculture’ and ‘pisciculture’?
• What is meant by disease resistance? Mention the two factors on which a successful breeding for disease resistance depends.
• What are the advantages of breeding for disease-resistance in plants?
• How is evaluation and testing of the new variety carried out?
• List the various steps involved in breeding a new genetic variety of a crop.
• What are the objectives of breeding for improving nutritional quality.
• Why hardening is essential for establishment of plantlets in the field?
• What is meant by plant tissue culture? Name two types of plant tissue culture.
• Describe few examples of nutritionally rich crop plants.
• Why does a beekeeper keep beehives in crop fields during the flowering periods? State any two advantages.