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CBSE Class 12 Board Exam 2018 : Biology

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SET-1 H$moS> Z . Series SGN Code No. amob Z . 57/1 narjmWu H$moS >H$mo C ma-nwp VH$m Ho$ _wI-n >na Ad ` {bIo & Roll No. Candidates must write the Code on the title page of the answer-book. H $n`m Om M H$a b| {H$ Bg Z-n _o _w{ V n > 11 h & Z-n _| Xm{hZo hmW H$s Amoa {XE JE H$moS >Z ~a H$mo N>m C ma-nwp VH$m Ho$ _wI-n > na {bI| & H $n`m Om M H$a b| {H$ Bg Z-n _| >26 Z h & H $n`m Z H$m C ma {bIZm ew $ H$aZo go nhbo, Z H$m H $_m H$ Ad ` {bI| & Bg Z-n H$mo n T>Zo Ho$ {bE 15 {_ZQ >H$m g_` {X`m J`m h & Z-n H$m {dVaU nydm _| 10.15 ~Oo {H$`m OmEJm & 10.15 ~Oo go 10.30 ~Oo VH$ N>m Ho$db Z-n H$mo n T>|Jo Am a Bg Ad{Y Ho$ Xm amZ do C ma-nwp VH$m na H$moB C ma Zht {bI|Jo & Please check that this question paper contains 11 printed pages. Code number given on the right hand side of the question paper should be written on the title page of the answer-book by the candidate. Please check that this question paper contains 26 questions. Please write down the Serial Number of the question before attempting it. 15 minute time has been allotted to read this question paper. The question paper will be distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the students will read the question paper only and will not write any answer on the answer-book during this period. Ord {dkmZ (g mp VH$) BIOLOGY (Theory) {ZYm [aV g_` : 3 K Q>o A{YH$V_ A H$ : 70 Time allowed : 3 hours 57/1 Maximum Marks : 70 1 P.T.O. gm_m ` {ZX}e : (i) Z-n _| nm M I S>m| _ o 26 Z {XE JE h & g^r Z A{Zdm` h & (ii) I S> A _| Z g `m 1 go 5 (iii) I S> h & 10 (iv) I S> C _| Z g `m H$m h & (v) I S> D _| Z g `m 23 _y ` AmYm[aV Z 4 A H$m| H$m h & (vi) I S> E _| Z g `m 24 go (vii) Z-n _| g_J na H$moB {dH$ n Zht h , {\$a ^r 2 A H$m| dmbo EH$ Z _|, 3 A H$m| dmbo EH$ Z _| Am a 5 A H$m| dmbo g^r VrZm| Zm| _| ^rVar M`Z-{dH$ n {XE JE h & `oH$ narjmWu H$mo Eogo Zm| Ho$ Xmo {dH$ nm| _ o go H$moB EH$ Z hb H$aZm h & B _| Z g `m 6 go 11 go A{V bKw-C mar` Z h , `oH$ Z 1 A H$ H$m h & bKw-C mar` Z H$ma I Ho$ h , `oH$ Z 22 26 bKw-C mar` Z H$ma II 2 Ho$ h , `oH$ Z A H$m| H$m 3 A H$m| XrK -C mar` Z h , `oH$ Z 5 A H$m| H$m h & General Instructions : (i) There are a total of 26 questions and five sections in the question paper. All questions are compulsory. (ii) Section A contains questions number 1 to 5, very short-answer type questions of 1 mark each. (iii) Section B contains questions number 6 to 10, short-answer type I questions of 2 marks each. (iv) Section C contains questions number 11 to 22, short-answer type II questions of 3 marks each. (v) Section D contains question number 23, value based question of 4 marks. (vi) Section E contains questions number 24 to 26, long-answer type questions of 5 marks each. (vii) There is no overall choice in the question paper, however, an internal choice is provided in one question of 2 marks, one question of 3 marks and all the three questions of 5 marks. In these questions, an examinee is to attempt any one of the two given alternatives. 57/1 2 I S> A SECTION A 1. dh Xmohao C o ` {b{IE {OZH$s ~h bH$sH$aU _| ny{V S>rAm gramB~mo `yp b`mogmBS> Q >mB\$m \o$Q> H$aVo h & 1 Write the dual purpose served by Deoxyribonucleoside triphosphates in polymerisation. 2. Xmo amoJm| Ho$ Zm_ {b{IE {OZH$m gma ES>r O _ N>am| Ho$ C _ybZ Ho$ mam {Z` { V {H$`m Om gH$Vm h & 1 Name two diseases whose spread can be controlled by the eradication of Aedes mosquitoes. 3. _mZd _| gmBQ>moH$mBZ amoY _mZd _| {H$g H$ma ghO {Vajm XmZ H$aVo h ? 1 How do cytokine barriers provide innate immunity in humans ? 4. {Z Z{b{IV Ho$ Zm_ {b{IE (a) 15 (b) 2 : 1 {_{b`Z df nyd dZ_mZwf (Eon) Ho$ g_mZ mB_oQ> {_{b`Z df nyd nydu A\ $sH$m Ho$ Kmg- Wbm| _| ahZo dmbo mB_oQ> Write the names of the following : 5. (a) A 15 mya primate that was ape-like (b) A 2 mya primate that lived in East African grasslands mH $-B gw{bZ _| hmoZo dmbo Cg amgm`{ZH$ n[adV Z H$m C oI H$s{OE {OgHo$ mam dh n[an d B gw{bZ H$s Vah H$m` H$aZo _| gj_ hmo OmVm h & 1 Mention the chemical change that proinsulin undergoes, to be able to act as mature insulin. 57/1 3 P.T.O. I S> B SECTION B 6. {~Zm-\$brXma Wbr` \$gb H$mo CJmZo Ho$ {bE {_ >r _| ZmBQ >moOZ H$s _m m _| gwYma hoVw AmnH$s gbmh _m Jr JB h & (a) Eogo Xmo gy _Ordm| H$s AZwe gm H$s{OE Omo {_ >r _| ZmBQ >moOZ H$m g dY Z H$a gH|$ & (b) \$brXma \$gbm| H$mo {_ >r Ho$ Bg H$ma Ho$ g dY Z H$s Amd `H$Vm `m| Zht hmoVr ? 2 Your advice is sought to improve the nitrogen content of the soil to be used for cultivation of a non-leguminous terrestrial crop. 7. (a) Recommend two microbes that can enrich the soil with nitrogen. (b) Why do leguminous crops not require such enrichment of the soil ? Eogm _mZm OmVm h {H$ {H$gr g_{ > _| EH$ OrZ H$s Eobrb Amd { m`m nr T>r Xa nr T>r EH$g_mZ ahVr h & hmS>u-doZ~J Zo ~rOJ{UVr` g_rH$aU H$s ghm`Vm go BgH$s `m `m {H$g H$ma H$s ? AWdm ` {n Agr_Ho$ H$s H$mo{eH$m _| n > Ho$ H$ Zht hmoVm, {\$a ^r S>r.EZ.E. nyar H$mo{eH$m _| \ $bm Zht hmoVm & `m `m H$s{OE & 2 2 With the help of an algebraic equation, how did Hardy-Weinberg explain that in a given population the frequency of occurrence of alleles of a gene is supposed to remain the same through generations ? OR Although a prokaryotic cell has no defined nucleus, yet DNA is not scattered throughout the cell. Explain. 8. g .am. A_o[aH$m Ho$ AH$m Q>m, H ${b\$mo{Z `m, Ho$ AH$m Q>m H$ N> Ho$ {_ Zm_H$ ZmJ[aH$ g_yh Zo EH$sH $V An{e > Ob CnMma mam H$ N> ^y{_ Ho$ Ob H$s JwUd mm gwYmaZo _| {H$g H$ma ghm`Vm H$s ? Mma MaUm| _| BgH$s `m `m H$s{OE & How did a citizen group called Friends of Arcata Marsh, Arcata, California, USA, help to improve water quality of the marshland using Integrated Waste Water Treatment ? Explain in four steps. 57/1 4 2 9. AmnH$mo A{YH$ CnO dmbr Q>_mQ>a H$s EH$ ZB {H$ _ m V h B h & Cg VH$ZrH$ H$m Zm_ {b{IE {OgHo$ mam Q>_mQ>a \$gb H$s ^mdr nr{ T>`m| H$s ~ S>r g_{ >`m| _| dm {N>V bjUm| H$s {Za VaVm ~ZmE aIZo H$mo gw{Zp MV {H$`m Om gHo$ & Bg {d{Y H$s `m `m ^r H$s{OE & 2 You have obtained a high yielding variety of tomato. Name and explain the procedure that ensures retention of the desired characteristics repeatedly in large populations of future generations of the tomato crop. 10. (a) (b) {hamoBZ S >J Ho$ moV nm Yo H$m Zm_ {b{IE & `h nm Yo go {H$g H$ma m V H$s OmVr h ? _mZd eara na {hamoBZ Ho$ ^mdm| H$mo {b{IE & (a) Name the source plant of heroin drug. How is it obtained from the plant ? (b) Write the effects of heroin on the human body. 2 I S> C SECTION C 11. nyU {dH${gV (n[an d) _mZd ewH $mUw H$m {M ~ZmBE & BgHo$ VrZ ^mJm| H$mo Zm_m {H$V H$a CZHo$ H$m` {b{IE & 3 Draw a diagram of a mature human sperm. Label any three parts and write their functions. 12. 13. (a) (b) dr.EZ.Q>r.Ama. H$m nyam Zm_ {b{IE VWm S>r.EZ.E. q\$Jaq qQ>J (S>r.EZ.E. A Jw{bN>mnr) _| BgH$s ^y{_H$m H$m dU Z H$s{OE & S>r.EZ.E. A Jw{bN>mnr VH$ZrH$ Ho$ H$moB Xmo AZw `moJ {b{IE & (a) Expand VNTR and describe its role in DNA fingerprinting. (b) List any two applications of DNA fingerprinting technique. A{ZfoH$\$bZ VWm A{ZfoH$OZZ _| {d^oX H$s{OE & `oH$ H$m EH$-EH$ CXmhaU ^r Xr{OE & 3 3 Differentiate between Parthenocarpy and Parthenogenesis. Give one example of each. 14. {M{H$ gm H$s { > go g^r `wdm _mVmAm| H$mo `h gbmh Xr OmVr h {H$ CZHo$ ZdOmV {eewAm| Ho$ {bE VZnmZ gdm} m_ h & `m Amn Bggo gh_V h ? H$maU g{hV AnZo C ma H$s nw{ > H$s{OE & 3 Medically it is advised to all young mothers that breastfeeding is the best for their newborn babies. Do you agree ? Give reasons in support of your answer. 57/1 5 P.T.O. 15. n{j`m| _| qbJ-{ZYm aU H$s {H $`m{d{Y H$s `m `m H$s{OE & _mZdm| _| qbJ-{ZYm aU go `h {H$g H$ma {^ h ? 3 Explain the mechanism of sex determination in birds. How does it differ from that of human beings ? 16. 17. (a) ~m`mo[aEo Q>a H$m {dH$mg O d- m mo{JH$s _| {H$g H$ma ghm`H$ h Am ? (b) gdm {YH$ Cn`moJ _| AmZo dmbo ~m`mo[aEo Q>a H$m Zm_ {bIH$a CgH$s H$m` {d{Y H$m dU Z H$s{OE & (a) How has the development of bioreactor helped in biotechnology ? (b) Name the most commonly used bioreactor and describe its working. nwZ`m}JO S>r.EZ.E. m mo{JH$s _| {Z Z{b{IV H$s ^y{_H$m H$s `m `m `oH$ Ho$ EH$-EH$ CXmhaU H$s ghm`Vm go H$s{OE : (a) {V~ YZ E OmB_ (b) bmp _S> 3 3 Explain the roles of the following with the help of an example each in recombinant DNA technology : 18. (a) Restriction Enzymes (b) Plasmids newnmbZ _| ~{h OZZ, ~{h g H$aU VWm nma- OZZ (g H$aU) n {V`m| H$s `m `m H$s{OE & 3 Explain out-breeding, out-crossing and cross-breeding practices in animal husbandry. 19. 57/1 (a) O {dH$ {H$gmZ amoJm| Ed nr S>H$m| Ho$ {Z` U Ho$ {bE agm`Zm| H$s Anojm O d {Z` U H$mo dar`Vm XoVo h & Am {M ` {g H$s{OE & (b) O d {Z` H$ Ho$ $n _| Cn`moJ {H$E OmZo dmbo OrdmUw, H$dH$ Ed H$sQ> H$m EH$ -EH$ CXmhaU Xr{OE & (a) Organic farmers prefer biological control of diseases and pests to the use of chemicals for the same purpose. Justify. (b) Give an example of a bacterium, a fungus and an insect that are used as biocontrol agents. 6 3 20. (a) (b) 21. g_ $n VWm g_OmV g aMZmAm| _| {d^oX H$s{OE & {Z Z{b{IV gyMr _| go g_ $n g aMZmAm| H$m M`Z H$aHo$ {b{IE (i) {VVbr Ed n{j`m| Ho$ n I (ii) H$eo H$s X` (iii) ~m JoZ{d{b`m Ed Hw$Hw$a{~Q>m Ho$ VmZ (iv) eH$aH $X Am a Amby Ho$ H $X : 3 (a) Differentiate between analogous and homologous structures. (b) Select and write analogous structures from the list given below : (i) Wings of butterfly and birds (ii) Vertebrate hearts (iii) Tendrils of bougainvillea and cucurbita (iv) Tubers of sweet potato and potato (a) Zm d} H$s Anojm ^maV _| nm[aV {d{dYVm A{YH$ h & `m Amn Bg H$WZ go gh_V h ? H$maU ~VmVo h E AnZo C ma H$s nw{ > H$s{OE & AmZwd {eH$ O d-{d{dYVm VWm OmVr` ( nrer O) O d-{d{dYVm _| A Va {b{IE Omo O {dH$ g JR>Z Ho$ g^r Vam| _| n[ab{jV hmoVo h & 3 AWdm O~ {H$gr ZXr _| ehar dm{hV _b H$m {dgO Z {H$`m OmVm h , Vmo ZXr Ho$ bjUm| na n S>Zo dmbo ^md H$s `m `m H$s{OE & 3 (b) (a) India has greater ecosystem diversity than Norway. Do you agree with the statement ? Give reasons in support of your answer. (b) Write the difference between genetic biodiversity and species biodiversity that exists at all the levels of biological organisation. OR Explain the effect on the characteristics of a river when urban sewage is discharged into it. 22. V ~mHy$ Ho$ nm Ym| _| {_ dmS>oJmBZ BZH$moJZr{e`m Ho$ g H $_U Ho$ {Z` U _| EJ mo~ Q>r[a`_ H$m g dmhH$ Ho$ $n _| Cn`moJ {H$g H$ma ghm`H$ ahm h ? ghr AZwH $_ _| `m `m H$s{OE & 3 How has the use of Agrobacterium as vectors helped in controlling Meloidegyne incognitia infestation in tobacco plants ? Explain in correct sequence. 57/1 7 P.T.O. I S> D SECTION D 23. dm`w- X fU Ho$ H$maU Xoe Ho$ AZoH$ eham| _| dm`w H$s JwUd mm Ho$ {JaVo Va H$mo boH$a ZmJ[aH$ ~h V A{YH$ qM{VV h Ed AnZo dm ` H$mo boH$a naoemZ ^r h & {OZ eham| _| dm`w H$s JwUd mm A ` V IVaZmH$ Va VH$ nh M MwH$s h , CZ_| {M{H$ gH$m| Zo dm ` AmnmV Kmo{fV H$a {X`m h & (a) dm`w- X fU Ho$ Xmo _wI H$maH$m| H$m C oI H$s{OE & (b) dm`w- X fU Ho$ H$maU nmXnm| Ed _mZdm| na n S>Zo dmbo H$moB Xmo hm{ZH$maH$ ^md {b{IE & (c) AnZo {d mb` Ho$ B H$mo- b~ Ho$ H $ Q>Z H$s h {g`V go {d mb` Ed Amgnmg Ho$ jo m| _| dm`w- X fU amoH$Zo Ho$ {bE {d m{W `m| _| OmJ $H$Vm A{^`mZ Ho$ Am`moOZ Ho$ {bE {H$ ht Xmo H$m` H $_m| H$m gwPmd Xr{OE & Looking at the deteriorating air quality because of air pollution in many cities of the country, the citizens are very much worried and concerned about their health. The doctors have declared health emergency in the cities where the air quality is very severely poor. (a) Mention any two major causes of air pollution. (b) Write any two harmful effects of air pollution to plants and humans. (c) As a captain of your school Eco-club, suggest any two programmes you would plan to organise in the school so as to bring awareness among the students on how to check air pollution in and around the school. 57/1 8 4 I S> E SECTION E 24. (a) nw nr nmXnm| H$s {H$ ht Xmo `w{ $`m| H$m dU Z H$s{OE Omo d`w _Z VWm na{ZfoMZ H$mo ~m{YV H$aVr h & (b) EH$ Amd V~rOr Ho$ ~rOm S> H$s {H$gr EH$ ghm` H$mo{eH$m _| namJZ{bH$m Ho$ doe Ho$ Cnam V { {ZfoMZ VH$ H$s n[aKQ>ZmAm| H$m dU Z H$s{OE & 5 AWdm (a) _mZd { `m| _| AmV d MH $ H$s `m `m H$s{OE & (b) _mZd { `m| _| AmV d MH $ H$s d km{ZH$ g_P J^ {ZamoYH$ Cnm` Ho$ $n _| {H$g H$ma ghm`H$ hmo gH$Vr h ? (a) Describe any two devices in a flowering plant which prevent both autogamy and geitonogamy. (b) Explain the events upto double fertilisation after the pollen tube enters one of the synergids in an ovule of an angiosperm. 5 OR 25. (a) Explain menstrual cycle in human females. (b) How can the scientific understanding of the menstrual cycle of human females help as a contraceptive measure ? (a) Cg Ord H$m d km{ZH$ Zm_ {b{IE {OgH$m Cn`moJ Wm _g h Q> _m J Z Am a CZHo$ gm{W`m| Zo AnZo `moJm| _| {H$`m Wm & OrZm| Ho$ g X^ _| ghb ZVm Am a nwZ`m}OZ Ho$ ~rM ghg ~ Y _| CZHo$ mam {H$E JE A ``Z H$s `m `m H$s{OE & (b) _m J Z Ho$ gmW H$m` H$aVo h E Q>Q>ud|Q> Zo OrZ {M U (OrZ _ qnJ) H$s `m `m {H$g H$ma H$s ? 5 AWdm 57/1 9 P.T.O. (a) \ ${gg {H $H$ mam {Vnm{XV _yb {g m V (go Q >b S>mo _m) {b{IE & `m BgHo$ Hw$N> AndmX ^r h ? H$maU ~VmVo h E EH$ CXmhaU H$s ghm`Vm go AnZo C ma H$s nw{ > H$s{OE & (b) $nm Var` {g m V H$s O damgm`{ZH$ H ${V H$m {ZYm aU {H$g H$ma h Am Omo {J {\$W Ho$ `moJm| mam n > Zht hmo nm`m Wm ? g_PmBE & (a) Write the scientific name of the organism Thomas Hunt Morgan and his colleagues worked with for their experiments. Explain the correlation between linkage and recombination with respect to genes as studied by them. (b) How did Sturtevant explain gene mapping while working with Morgan ? 5 OR 26. (a) State the Central dogma as proposed by Francis Crick. Are there any exceptions to it ? Support your answer with a reason and an example. (b) Explain how the biochemical characterisation (nature) of Transforming Principle was determined, which was not defined from Griffith s experiments. (a) {d{^ AO d H$maH$m| Ho$ {V {d{^ O VwAm| H$s {Z Z{b{IV AZw{H $`mE n[ab{jV hmoVr h & `oH$ Ho$ EH$-EH$ CXmhaU H$s ghm`Vm go BZH$m dU Z H$s{OE & (i) {Z`_Z H$aZm (ii) g $nU aIZm (iii) dmg H$aZm (iv) {Zb {~V H$aZm (b) 80 {VV{b`m| H$s EH$ g_{ > _| `{X EH$ g Vmh _| 8 {VV{b`m| H$s _ `w hmo OmVr h , Vmo Cg Ad{Y _| {VV{b`m| H$s g_{ > H$s _ `w Xa H$s JUZm H$s{OE & AWdm 57/1 10 5 {H$gr nm[aV _| nmofU Va `m hmoVm h \$gb) H$m `m A{^ m` h ? (b) {H$gr nm[aV _| W_ nmofH$ Va H$s ^y{_H$m H$s `m `m H$s{OE & EH$ mH ${VH$ nm[aV _| AnaX Im m Ibm, MmaU Im m Ibm go {H$g H$ma g ~ h ? (c) (a) (b) ? BgHo$ g X^ _| p WV e ` (I S>r (a) 5 Following are the responses of different animals to various abiotic factors. Describe each one with the help of an example. (i) Regulate (ii) Conform (iii) Migrate (iv) Suspend If 8 individuals in a population of 80 butterflies die in a week, calculate the death rate of population of butterflies during that period. OR 57/1 (a) What is a trophic level in an ecosystem ? What is standing crop with reference to it ? (b) Explain the role of the first trophic level in an ecosystem. (c) How is the detritus food chain connected with the grazing food chain in a natural ecosystem ? 11 P.T.O.

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