24277 + Interview Questions in Biology in Class 12 Page 454 InterviewSolution

22651.	Question : According to Oparin and Haldane, transformation of lifeless chemicals into living matter extended
Answer» 1 BILLION YEARS 2 billion years 3 billion years 4 billion years Answer :C

Discussion

22652.	Question : [A]: When platelets disintegrate, 5-hydroxy tryptamine and histamine are liberated. [R]: Speed of clot reaction is directly propor- tional to the number of platelets present.
Answer» If both A and R are TRUE and R is the correct EXPLANATION of A If both A and R are true but R is not the correct explanation of A If A is true and R is false If both A and R are false Answer :B

Discussion

22653.	Question : According to observations of Human Genome project, which chromosome has minimum genes ?
Answer» On SOMATIC CHROMOSOME in Y Both X Y in X SOLUTION :in Y

Discussion

22654.	Question : [A]: When doing genetics problems, firs de- cide the appropriate key and then determine the genotype and gametes for both parents. [R]: It is necessary to keep in mind that al- though an individual has two alleles for each trait, each gamete has only one allele for each trait
Answer» If both A and R are true and R is the correct EXPLANATION of A If both A and R are true but R is not the correct explanation of A If A is true and R is FALSE If both A and R are false ANSWER :A

Discussion

22655.	Question : According to noise pollution rules 2000, the permissible level of noise in commercial area is during day and .............. during night
Answer» 55 DB, 65 db 65 db, 55 db 70 db, 60 db 75 db, 65 db Solution :65 db, 55 db

Discussion

22656.	Question :a. When and where does spermatogenesis in a human male begin to take place? b. With the help of schematic labelled diagrams, trace the development of mature spermatozoa in a human male? c. Describe the structure of a human sperm.
Answer» Solution :a. In testis, the immature male germ CELLS (spermatogonia) PRODUCE sperms by spermatogenesis that begins at puberty. The structure of a sperm is divided into a head, neck, a MIDDLE piece and a tail. A plasma membrane envelops the whole body of sperm. The anterior portion of which is covered by a cup like structure called acrosome. Acrosome is filled with enzymes that help FERTILISATION of the ovum. The middle piece, possesses numerous mitochondria which produce energy for the MOVEMENT of tail that facilitate sperm motility essential for fertilisation.

Discussion

22657.	Question : According to Mercer's Index of "world's most liveable cities", which city topped the index?
Answer» NEW York Paris London VIENNA ANSWER :D

Discussion

22658.	Question : A wheat variety resistant to hill bunt discase is ………. .
Answer» PUSA Shubhra Himgiri Pusa gaurav Pusa swarnim Answer :B

Discussion

22659.	Question :According to modern scheme of photosynthetic electron transport the correct sequence of electron transfer from excited 9700 to NADP + is
Answer» `A_(1) rarr A_(0) rarr F_(x) rarr F_(A)//F_(B) rarr Fd rarr NADP^(+)` `A_(1) rarr A_(0) rarr F_(A) //F_(B) rarr FX rarr FNR rarr NADP^(+)` `A_(0) rarr A_(1) rarr F_(A) //F_(B) rarr Fx rarr NADP` `A_(0) rarr A_(1) rarr Fx rarr F_(A) //F_(B) rarr Fd rarr NADP^(+)` Answer :D

Discussion

22660.	Question : A wheat crop is ripening in the field. This shows
Answer» TRANSFER of ENERGY transformation of energy entropy none of the above ANSWER :A

Discussion

22661.	Question : According to Mendel's law of purity of gametes, I. In F_(1)hybrid, the dominant and recessive character though remain together for long time but do not contaminate or mix with each other. ii. The inheritance of one character is always independent to the inheritance of other character within the same individual. III. the gamete formed contains the factor, which determines single trait pertaining to a particular characteriv. two genes of allelomorphic pair are not related as dominant or recessive but each of them express itself partially.Choose the correct option.
Answer» I and II III and IV I and IV II and III Answer :A

Discussion

22662.	Question : A wheat variety, Atlas 66 which has been used as a donor for improving cultivated wheat, which is rich in
Answer» (a) IRON (B) carbonhyrates (C) PROTEINS (d) vitamins Answer :C

Discussion

22663.	Question : (a) What is adaptive radiation. (b) Explain with the help of suitable example where adaptive radiation has occurred to represent convergent evolution.
Answer» Solution :(a) Adaptive radiation refers to the process of evolution of different speciesin a GIVEN geographical area starting from a point and literally radiating to other areas (B) Australian MARSUPIALS represent one of the best examples of adaptive radiation. A number of marsupials, each different from the other evolved from an ancestral stock. but all within the Australian island CONTINENT When more than one adaptive radiation appeared to have occurred in an isolated geographical area (representing different habitats]. it is called convergent evolution. (Darwin finches and placental mammals in Australia also exhibit adaptive radiation)

Discussion

22664.	Question : (a) What is a tropihic level in an ecosystem? What is standing crop with reference to it ? (b) Explain the role of the first troplhic level in an ecosystem . (c ) How is the detritus food chain connected with the grazingfood chain in a natural ecosystem?
Answer» Solution :(a) tropic level : organisms occupy a plce in the natureal SURROUNDING or ina community accroding to their feeding relationshio with other organisms .Based on the source of their nutrition or gfood organisms occupu a specifice place in the food chain and this is knwo as trophic level (b) First trophic level is formed by prducer theis is the basic unit these organisms can live without feeding on any another level.The only THING that these organisms need to sur vie is sunlight and water which they can turn into energy themselves .all other trophic level DEPENDS on thius for energy . (c ) GFC is GRAZING food chain : it is depicted as below: Grass`rarr`Deer`rarr`Lion DFC is detritus food chain : It begin withdead organic matter .It is made up of decomposers which are hetyerotyrophic organisms like fungi bactgreria etc GFC is the MAJOR condut for energy flow .DFC may be connected with GFC at some levels : some of the organisms of DFC are prey to the GFC animlas.

Discussion

22665.	Question : According to Mendel, which is not a dominant trait ?
Answer» WRINKLED seeds Purple flower INFLATED POD form AXIAL flower portion Answer :A

Discussion

22666.	Question : (a) What in plasmid? (b) What is meant by ADA dehciency ? How is gene therapy a solution to this problem ? Why is it not a permanent cure ?
Answer» Solution : (a) Plasmid refers to the extra chromosomal circular DNA molecule that replicate. AUTONOMOUSLY in a BACTERIAL cell. (b) Adenosine deaminase (ADA) deficiency. It is associated with (SCID) severe combined immunodeficiency. ADA is very crucial for immune systems to function. The deficiency of ADA causes severe combined immune deficiency disease. The patient lacks functional T-lymphocyteo and fails to fight the infections pathogens. Using the gene-therapy lymphocytes are extracted from the patient’s bone marrow and a normal functional gene for ADA is introduced into these lymphocytes with the help of the retro virus. The lymphocyctes of bone marrow contains the functional ADA gene and reactivate the patient’e immune SYSTEM. In some CHILDREN, ADA deficiency can be treated bone marrow transplantation, in other it can be treatedby enzyme replacement therapy, in which functional ADA is given to the patient by injection. But the problem with both of these approaches that they are not completely curative.

Discussion

22667.	Question : According to Lock and Key Hypothesis
Answer» Both enzyme and substrate molecules have specific geometrical shapes Only ENZYMES have a fixed shape Only SUBSTRATES have a fixed shape Only products have specific shape which is COMPATIBLE to the enzyme's ACTIVE site Answer :A

Discussion

22668.	Question : (a) What did Meselson and Stahl observe when : (i) They cultured E. coli in a medium containing ""^(15)NH_(4)Cl for a few generations and centrifuged the content (ii) They transferred one such bacterium to the normal medium of NH_(4)CI and cultured for 2 generations (iii) What did Meselson and Stahl conclude from this experiment ? Explain with the help of diagram. (iv) Which is the first genetic material ? Give reasons in support of your answer.
Answer» SOLUTION :(i), (II) and (III)

Discussion

22669.	Question : According to Lamrckicm, long necked giraffes evolved because
Answer» nature SELECTED only long necked ones humans preferred only long necked ones short NECKS SUDDENLY CHANGED into long necks of stretching of necks over many generations by short necked ones. Answer :D

Discussion

22670.	Question : (a) What do 'Y' and 'B' stand for in 'YAC' and 'BAC' used in Human Genome Project (HGP). Mention their role in the project. (b) Write the percentage of the total human genome that codes for proteins and the percentage of discovered genes whose functions are known as observed during HGP. (c) Expand 'SNPs' identified by scientists in HGP.
Answer» SOLUTION :(a) The BAC (BACTERIAL artificial Chromosomes and YAC (Yeast artificial chromosomes) represent the host cells used for cloning of DNA fragments using specialized vectors. (b) Less than 2 PERCENT of the human genome codes for proteins. Less than 50 percent of the discovered genes have their functions known. (c) SNP: Single nucleotide POLYMORPHISM. These are sites for single DNA BASE differences. SNPS hold promise for location of disease-associated sequences on chromosomes and tracing human history.

Discussion

22671.	Question : According to Lamarckism, long necked giraffes evolved because
Answer» nature slected only long necked ONES humans preferred only long necked ones short necks suddenly changed into long necks of strethcing ofnecks over many generations by short necked ones. Solution :According to Lamarckism, the ancestors of giraffe had small neck and forelimbs and were like HORSES. They were residing in places with no surface VEGETATION, THEREFORE, they had to stretch their neck and forelimbs to take the leaves for food. This LED to slight elongation of these parts. Whatever they acquired in one generation was trasnmitted to the next generation with the result that a race of long forelimbed giraffes were developed.

Discussion

22672.	Question : According to IUCN ( 2004 ) , the total number of plant and animal species described so far is slightly more than ____________________
Answer» 1.5 MILLION 2.5 million 3.5 million 4.5 million Answer :D

Discussion

22673.	Question :(a) What depletes ozone in the stratosphere? How does this affect human life? (b) Explain biomagnification of DDT in an aquatic food chain. How does it affect the bird population?
Answer» Solution : (a) The thin layer of ozone around the atmosphere that prevents entry of harmful UV rays is CALLED ozone shield. Methane and chlorfloro carbons are the two ozone DEPLETING substances. CFCS release active chlorine (Cl atoms) when acts with UV rays and Cl atoms degrade ozone releasing MOLECULAR oxgen. Depletion of ozone allows the entry of UVB radiation to the earth which DAMAGES DNA. This causes mutation leading to skin cancer in humans and also rate of photosynthesis decreases in plants. (b) Biomagnification is the increase in concentration of toxic MATERIALS like heavy metals and pesticides at each trophic level of a food chain due to their accumulation in fat. The population of fish-eating birds living on the bank shows biomagnification of insecticides. DDT being highly, poisonous causes the thinning of their egg-shells and population of birds declines.

Discussion

22674.	Question : According to imbibition theory I. ascent of sap could takes place by imbibition through the walls of xylem. II. Water can rise through the wall due to imbibitional pressure upto a certain height only. III. The pressure at the transpiring surface falls below that of atmsophere. IV. rate of transpiration is roughly equal to the rate of imbibition.
Answer» I and II II and IV Only IV Only III Answer :A

Discussion

22675.	Question : (a) What are the effects of ozone depletion? (B)BOD is an index of water pollution. Comment.
Answer» Solution :The BOD TEST measures the rate of UPTAKE of oxygen by microorganisms in a sample of water and thus INDIRECTLY BOD is a measure of the ORGANIC matter present in the water. The greater the BOD of waste water, more is its POLLUTING potential.

Discussion

22676.	Question : According to immunity theory, ageing is due to
Answer» Accumlation of ERRORS Rediced functioning of endocrine glands DEGENERATION of thymus Accumulation of waste PRODUCTS Solution :According to immuity THEORY, ageing is due to degeneration of thymus.

Discussion

22677.	Question : a. What are the features of an ideal contraceptive? b. Mention the natural methods of contraception.
Answer» Solution :a. The features of an ideal CONTRACEPTION are They should be USER friendly They should be easily available They should not effective and show side EFFECTS They not interfere with SEXUAL desire and sexual act of user. b. The natural methods of contraception are: Periodic abstinence Withdrawal method Lactational amenorrhoea

Discussion

22678.	Question : According to immunity theory ,ageing is due to
Answer» ACCUMULATION of errors Reduced FUNCTIONING of ENDOCRINE glands Degeneration of thymus Accumulation of WASTE products. Answer :C

Discussion

22679.	Question : a. What are molecular scissors ?Give one example .b. Explain their role in recombinant DNA technology .
Answer» Solution :a. These are restriction ENDONUCLEASES which CUT the DNAmolecule into fragments with sticky ends. b.The enzyme restriction endonuclease cleaves DNA at specific site resulting in the formation of stickyends. In practice,the digestion by the restriction enzyme is performed by INCUBATION of the puri-fied DNA molecules with the specific enzyme KEEPING all other conditions at the optimum level and CHECKED by using agarose gel electrophoresis .

Discussion

22680.	Question : According to Hugo deVries what causes evolution?
Answer» SMALL and CONTINUOUS variations Small and DISCONTINUOUS variations Large and discontinuous variations large and continuous variations Answer :C

Discussion

22681.	Question : During embryonic development some parts of the embryo differentiate into a set of membranes called extra embryonic membrane. a. Name the extra embryonic membrane. b. Mention its importance in the embryonic development.
Answer» Solution :(a)The extra embryonic membranes include amnion, yolk sac, allantois and chorion. They protect the embryo from dessication, mechanical shock, absorption of nutrients, gaseous exchange and placental formation. (b)LIST out of the effects of air pollution. •Affects all organisms as they DEPEND on the atmosphere for respiration. • Causes irration in the throat, nose, lungs and eys. It causes breathing problems and aggravates existing health conditions such as emphysema and asthma. •Contaminated air reduces the body.s defense mechanism and decreases the body.s capacity to fight other infections in the respiratory system. •Frequent exposure to polluted air increases the risk of cardiovascular diseases. Breathing air that is filled with fine particulate matter can induce hardening of the arteries, triggering cardiac arrhythmia or even a heart attack. •People who exercise outdoors can sometimes be susceptible to ADVERSE effects of air pollution because it involves deeper and faster breathing. Hence it is advisable to walk or jog in the mornings in places with AMPLE tree cover. •Gas leaks can be lethal or affect the QUALITY of air in the affected area. •CO in the atmosphere interferes with `O_(2)` transport since haemoglobin has greater affinity for carbon monoxide. At low concentration it causes headache and blurred vision. In higher concentration, it can lead to coma and death.

Discussion

22682.	Question : According to Hugo deVries mutations are:
Answer» Large Random Directionless All of the above Answer :D

Discussion

22683.	Question : A) What are false fruits? Give an example. B) Write the characteristie features of insect pollinated flowers.
Answer» Solution :a) The fruits develop from the part other than ovary i.e., thalamus is called false fruits. Ex: apple, strawberry, cashew. b) Characteristics I. The flowers are large, conspicuous, coloured and showy. II. When flowers are small, they AGGREGATE in the form of an inflorescence. III. The flowers have a fragrance and sweet nectar. IV. Pollengrains are rough and SURROUNDED by sticky substance called pollenkitt. V. Flowers are very good places for the insects to lay their eggs. Ex: Yucca, FICUS.

Discussion

22684.	Question : According to Hardy-Weinberg principle, allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences. It makes several assumption which were given below i. Random Mating ii. Sexual Reproduction iii. Non-overlapping Generations iv. Occurrence of Natural Selection v. Small size of population Identify two assumptions which do not meet for a population of reach Hardy-Weinberg Equilibrium ?
Answer» IV and v II and iv iii, iv and v i, ii and iii Answer :A

Discussion

22685.	Question : A well preserved and most complete homonid fossil named Lucy belongs to genus
Answer» Dryopithecus Oreopithecus Pithecanthropus Australopithecus. Solution :ASSORTATIVE Mating. Selective mating between genetically related individuals having SIMILAR traits CARRIED over generations can THEORETICALLY form new species without geographical ISOLATION.

Discussion

22686.	Question : According to Hugo de - Vries, the mechanism of evolution is
Answer» Minor MUTATIONS MULTIPLE step mutations Phenotypic VARIATIONS SALTATION SOLUTION :Multiple step mutations

Discussion

22687.	Question : A well developed archegonium with neck consisting of 4-6 rows of neck canal cells,characterises
Answer» GYMNOSPERMS only bryophytes and pteridophytes pteridophytes and gymnosperms gymnosperms and flowering plants Solution :(b) ARCHEGONIUM is te flask-shaped female REPRODUCTIVE body of bryophytes and pteridophytes.Archegonium usually consists ofa tubular neck and a swollen venter. Neck is made up of 4-6vertical row of cells and encloses 6-10 neck CANAL cells in bryophytes and 4 vertical rows in pteridophytes enclosing 1-4 neck canal cells. Venter has 1-2 layer but itt is wall-less in pteridophytes.

Discussion

22688.	Question : According to Hugo de Vries the mechanism of evolution is
Answer» Saltation Phenotypic variations Multiple STEPS mutations Minor mutations Answer :A

Discussion

22689.	Question : A waxy thick layer generally covers the epidermis which prevent water loss it is absent in
Answer» Stem Root LEAVES Flower Answer :B

Discussion

22690.	Question : According to Haberland, which of the following is not developed from ground meristem :-
Answer» Hypodermis Xylem Pericycle Pith Answer :B

Discussion

22691.	Question : A well developed archegonium with neck consisting of 4 - 6 rows and neck canal cells , characterises
Answer» GYMNOSPERMS and FLOWERING plants Pteridophytes and gymnosperms Gymnosperms only Bryophytes and pteridophytes Answer :D

Discussion

22692.	Question : According to Fisher, Rh antigen is controlled by how many closely linked genes?
Answer» 3 4 5 6 Answer :A

Discussion

22693.	Question : A Volcano erupted in Hawaii, and lava covered land that had been farmed for centuries. Eventually, new lichens, and then plants, grew on the lava. Is this an example of primary or secondary successions? Give the reason also.
Answer» Solution :This is an EXAMPLE of PRIMARY SUCCESSION. Because it begins from a state of LITTLE or no life.

Discussion

22694.	Question : According to EFB, "The integration of natural science and organisms, cells, parts ther of and molecular analogues for products and services," is
Answer» BIOCHEMISTRY BIOINFORMATICS BIOTECHNOLOGY Biology Solution :Biotechnology

Discussion

22695.	Question : A Volcano erupted in Hawaii, and lava covered land that had been farmed for centuries. Eventually, new lichens, and then plants, grew on the lava. Give the reason.
Answer» Solution :This is an EXAMPLE of primary SUCCESSION becausethis BEGINS from a state of little or no LIFE.

Discussion

22696.	Question : According to deep sea vents hypothesis, primitive sea was
Answer» Acidic Neutral Alkaline Both (a) and (B) ANSWER :C

Discussion

22697.	Question : A Volcano erupted in Hawaii, and lava covered land that had been farmed for centuries. Eventually, new lichens, and then plants, grew on the lava. Give the reaosn also.
Answer» SOLUTION :Because it BEGINS from a STATE of LITTLE or no LIFE.

Discussion

22698.	Question : According to David Tilman, greater the diversity, greater is the primary productivity. Can you think of a very low diversity man-made ecosystem that has high productivity ?
Answer» Solution :Agricultural FIELDS like WHEAT field/paddy field which are ALSO examples of MONOCULTURE PRACTICES.

Discussion

22699.	Question : A Volcano erupted in Hawaii, and lava covered land that had been farmed for centuries. Eventually, new lichens, and then plants, grew on the lava. Is this an example of primary or secondary successions?
Answer» SOLUTION :This is an EXAMPLE of PRIMARY SUCCESSION.

Discussion

22700.	Question : A viral DNA can be made radioactive.
Answer» <P>by CULTURING the viruseson a mediumof POTATO, dectrose and `P^(32)` by culturing thevirusesin a mediumof `P^(32)` by providing`P^(32)` to a BACTERIUM, which has been infected by a virus by providing `P^(32)` to VIRUSES when theyareaboutto attach the bacteria Answer :C

Discussion

Explore topic-wise InterviewSolutions in .

Question : According to Oparin and Haldane, transformation of lifeless chemicals into living matter extended

Question : [A]: When platelets disintegrate, 5-hydroxy tryptamine and histamine are liberated. [R]: Speed of clot reaction is directly propor- tional to the number of platelets present.

Question : According to observations of Human Genome project, which chromosome has minimum genes ?

Question : [A]: When doing genetics problems, firs de- cide the appropriate key and then determine the genotype and gametes for both parents. [R]: It is necessary to keep in mind that al- though an individual has two alleles for each trait, each gamete has only one allele for each trait

Question : According to noise pollution rules 2000, the permissible level of noise in commercial area is during day and .............. during night

Question :a. When and where does spermatogenesis in a human male begin to take place? b. With the help of schematic labelled diagrams, trace the development of mature spermatozoa in a human male? c. Describe the structure of a human sperm.

Question : According to Mercer's Index of "world's most liveable cities", which city topped the index?

Question : A wheat variety resistant to hill bunt discase is ………. .

Question :According to modern scheme of photosynthetic electron transport the correct sequence of electron transfer from excited 9700 to NADP + is

Question : A wheat crop is ripening in the field. This shows

Question : A wheat variety, Atlas 66 which has been used as a donor for improving cultivated wheat, which is rich in

Question : (a) What is adaptive radiation. (b) Explain with the help of suitable example where adaptive radiation has occurred to represent convergent evolution.

Question : (a) What is a tropihic level in an ecosystem? What is standing crop with reference to it ? (b) Explain the role of the first troplhic level in an ecosystem . (c ) How is the detritus food chain connected with the grazingfood chain in a natural ecosystem?

Question : According to Mendel, which is not a dominant trait ?

Question : (a) What in plasmid? (b) What is meant by ADA dehciency ? How is gene therapy a solution to this problem ? Why is it not a permanent cure ?

Question : According to Lock and Key Hypothesis

Question : According to Lamrckicm, long necked giraffes evolved because

Question : According to Lamarckism, long necked giraffes evolved because

Question : According to IUCN ( 2004 ) , the total number of plant and animal species described so far is slightly more than ____________________

Question :(a) What depletes ozone in the stratosphere? How does this affect human life? (b) Explain biomagnification of DDT in an aquatic food chain. How does it affect the bird population?

Question : (a) What are the effects of ozone depletion? (B)BOD is an index of water pollution. Comment.

Question : According to immunity theory, ageing is due to

Question : a. What are the features of an ideal contraceptive? b. Mention the natural methods of contraception.

Question : According to immunity theory ,ageing is due to

Question : a. What are molecular scissors ?Give one example .b. Explain their role in recombinant DNA technology .

Question : According to Hugo deVries what causes evolution?

Question : During embryonic development some parts of the embryo differentiate into a set of membranes called extra embryonic membrane. a. Name the extra embryonic membrane. b. Mention its importance in the embryonic development.

Question : According to Hugo deVries mutations are:

Question : A) What are false fruits? Give an example. B) Write the characteristie features of insect pollinated flowers.

Question : A well preserved and most complete homonid fossil named Lucy belongs to genus

Question : According to Hugo de - Vries, the mechanism of evolution is

Question : A well developed archegonium with neck consisting of 4-6 rows of neck canal cells,characterises

Question : According to Hugo de Vries the mechanism of evolution is

Question : A waxy thick layer generally covers the epidermis which prevent water loss it is absent in

Question : According to Haberland, which of the following is not developed from ground meristem :-

Question : A well developed archegonium with neck consisting of 4 - 6 rows and neck canal cells , characterises

Question : According to Fisher, Rh antigen is controlled by how many closely linked genes?

Question : A Volcano erupted in Hawaii, and lava covered land that had been farmed for centuries. Eventually, new lichens, and then plants, grew on the lava. Is this an example of primary or secondary successions? Give the reason also.

Question : According to EFB, "The integration of natural science and organisms, cells, parts ther of and molecular analogues for products and services," is

Question : A Volcano erupted in Hawaii, and lava covered land that had been farmed for centuries. Eventually, new lichens, and then plants, grew on the lava. Give the reason.

Question : According to deep sea vents hypothesis, primitive sea was

Question : A Volcano erupted in Hawaii, and lava covered land that had been farmed for centuries. Eventually, new lichens, and then plants, grew on the lava. Give the reaosn also.

Question : According to David Tilman, greater the diversity, greater is the primary productivity. Can you think of a very low diversity man-made ecosystem that has high productivity ?

Question : A Volcano erupted in Hawaii, and lava covered land that had been farmed for centuries. Eventually, new lichens, and then plants, grew on the lava. Is this an example of primary or secondary successions?

Question : A viral DNA can be made radioactive.