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CBSE Class 12 Board Exam 2019 : Biology (Series 3)

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SET-1 H$moS> Z . Series BVM/3 Code No. amob Z . 57/3/1 narjmWu H$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 _| >27 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 27 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 57/3/1 Maximum Marks : 70 1 P.T.O. gm_m ` {ZX}e : (i) Z-n _| Mma I S>m| _ o Hw$b 27 Z {XE JE h & g^r Z A{Zdm` h & (ii) I S> A _| Z g `m 1 go (iii) I S> ~ _| Z g `m 6 go (iv) I S> g _| Z g `m 13 go 24 bKw-C mar` Z H$ma II Ho$ h , `oH$ Z 3 A H$m| H$m h & (v) I S> X _| Z g `m 25 go 27 XrK -C mar` Z h , `oH$ Z 5 A H$m| H$m h & (vi) Z-n _| g_J na H$moB {dH$ n Zht h , {\$a ^r 1 A H$ dmbo Xmo Zm| _|, 2 A H$m| dmbo Xmo Zm| _|, 3 A H$m| dmbo Mma Zm| _| 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$aZm h & 5 A{V 12 bKw-C mar` Z h , `oH$ Z 1 A H$ H$m h & bKw-C mar` Z H$ma I Ho$ h , `oH$ Z 2 A H$m| H$m h & (vii) Amd `H$VmZwgma, {M m| H$m aoIZ gm\$-gwWam Ed `Wmo{MV bo~b hmoZm Mm{hE & General Instructions : (i) There are a total of 27 questions and four 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 12, short-answer type I questions of 2 marks each. (iv) Section C contains questions number 13 to 24, short-answer type II questions of 3 marks each. (v) Section D contains questions number 25 to 27, long-answer type questions of 5 marks each. (vi) There is no overall choice in the question paper, however, an internal choice is provided in two questions of 1 mark, two questions of 2 marks, four questions 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. (vii) Wherever necessary, the diagram drawn should be neat and properly labelled. 57/3/1 2 I S> A SECTION A 1. bmoZ Ordm| _| {d{dYVm n[ab{jV `m o Zht hmoVr ? Xmo H$maU {b{IE & 1 Why are no variations seen in clones ? State two reasons. 2. EH$ S>r.EZ.E. `yp b`moQ>mBS> VWm EH$ Ama.EZ.E. `yp b`moQ>mBS Ho$ _ ` A Va n > H$s{OE & 1 Differentiate between a DNA and a RNA nucleotide. 3. S>r d r O Ho$ AZwgma gm Q>oeZ `m h ? 1 What is Saltation according to de Vries ? 4. Cg Ord H$m d km{ZH$ Zm_ {b{IE {Og na H$m` H$aVo h E Abo O|S>a boq_J Zo {VO {dH$ H$s gd W_ ImoO H$s & C hm|Zo {Og Ord na H$m` {H$`m dh H$dH$ Wm AWdm OrdmUw ? AWdm 1 A `{YH$ A V: OZZ AdgmXZ H$s g_ `m Ho$ {ZXmZ hoVw EH$ {d{Y H$m gwPmd Xr{OE & 1 Write the scientific name of the organism Alexander Fleming worked on and discovered the first antibiotic. Was the organism he worked on a fungus or a bacterium ? OR Suggest a method to overcome excessive inbreeding depression. 5. Eo Q>mH ${Q>H$ jo _| Amo OmoZ-{N> Ho$ {bE C maXm`r X fH$ H$m Zm_ {b{IE & 1 AWdm 1 H$m~ Z S>mBAm gmBS> Ho$ A{V[a $ J rZhmCg J gm| H$s gyMr ~ZmBE & Name the pollutant attributed to be the cause of ozone-hole over the Antarctica region. OR List the greenhouse gases other than carbon dioxide. 57/3/1 3 P.T.O. I S> ~ SECTION B 6. 7. (a) Joh Ho$ nw n Ho$ {H$ ht Xmo {d{e Q> A{^bjUm| H$s gyMr ~ZmBE Omo Bgo dm`w namJU H$m EH$ A N>m CXmhaU ~ZmVo h & (b) Eogm XoIm J`m h {H$ Joh Ho$ g H$aU Ho$ {bE nmXn OZH$ ~h Ym namJ ~ H$ go namJH$Um| H$mo m V H$a CZH$m Cn`moJ H$aVo h & `m Amn Bggo gh_V h ? AnZo C ma Ho$ g_W Z _| EH$ H$maU Xr{OE & (a) List any two characteristic features of wheat flowers that make it a good example of wind pollination. (b) It is observed that plant breeders carrying out wheat hybridisation often take pollen grains from the pollen banks . Do you agree ? Give one reason in support of your answer. Q>Z a qgS >mo_ VWm S>mCZ {g S >mo_ _| A Va n Q> H$s{OE & 2 2 Differentiate between Turner s syndrome and Down s syndrome. 8. {Vajm AZw{H $`m H$mo {dH${gV H$aZo _| ~r-bgrH$mUwAm| VWm Q>r-bgrH$mUwAm| Ho$ _ ` g ~ Y H$s `m `m H$s{OE & 2 Explain the relationship between B-lymphocytes and T-lymphocytes in developing an immune response. 9. ^maV gaH$ma Zo Or.B .E.gr. Zm_H$ g WmZ H$s WmnZm `m| H$s ? H$moB Xmo H$maU {b{IE & 2 AWdm mH $-B gw{bZ Ho$ B gw{bZ _| $nm VaU H$m `d Wm _H$ {Z $nU Xr{OE & Why has the Indian Government set up the organisation named GEAC ? Give any two reasons. OR Give a schematic representation of the transformation of a pro-insulin into insulin. 57/3/1 4 2 10. Ori `m h ? g dmhH$ H$s bmoqZJ _| BgH$m _h d {b{IE & AWdm 2 EH$ C{MV CXmhaU H$s ghm`Vm go daU`mo ` {M H$ Ho$ _h d H$s `m `m H$s{OE & 2 What is Ori ? State its importance during cloning of a vector. OR Explain the importance of selectable marker , with the help of a suitable example. 11. {H$gr Amdmg _| EH$ Om{V H$s nmofU j_Vm `m h ? g ^ma-V (bm {Op Q>H$) d { _m S>b H$mo A{YH$ `WmW nyU `m| _mZm OmVm h ? 2 What is carrying capacity of a species in a habitat ? Why is logistic growth model considered more realistic ? 12. D$Om H$m {na {_S> gX d D$ dm Ya (I S>r) Ad Wm _| hmoVm h VWm H$^r AYmo_wIr Zht hmo gH$Vm & H$WZ H$s `m`g JVVm {g H$s{OE & 2 Justify the statement, Pyramid of energy is always upright, and can never be inverted. I S> g SECTION C 13. AnZo eham| _| A{V J ^ra dm`w X fU H$s g_ `m Ho$ g_mYmZ hoVw {H$ ht VrZ gwYmam _H$ Cnm`m| H$s `m `m H$s{OE & AWdm d{Z X fU Ho$ Eogo H$moB VrZ VarHo$ {b{IE Omo _mZd eara na X ^md S>mbVo h & d{Z X fU H$mo H$_ H$aZo Ho$ {bE AnZmE OmZo dmbo {H$ ht VrZ Cnm`m| H$s gyMr ~ZmBE & 3 3 Explain any three remedial measures to overcome the acute air pollution in our cities. OR Write any three ways by which noise pollution affects the human body adversely. List any three steps that should be followed in order to reduce noise pollution. 57/3/1 5 P.T.O. 14. (a) {H$gr nm[aV H$s mW{_H$ C nmXH$Vm `m h VWm Bgo {H$g H$ma ` $ H$aVo h (b) {Z Z{b{IV g_rH$aU `m Xem Vm h , CgH$s `m `m H$s{OE & EZ.nr.nr. = Or.nr.nr. ? 3 Ama AWdm (a) Cg H$ma Ho$ AnaX H$m Zm_ {b{IE {Oggo AnKQ>Z Vrd J{V go hmoVm h & Eogo {H$ ht Xmo H$maH$m| H$s gyMr ~ZmBE Omo AnKQ>Z H$s Xa H$mo ~ T>mVo h & (b) AnKQ>Z H $_ Ho$ Xm amZ y_r{\$Ho$eZ VWm I{ZOrH$aU {H $`m Ho$ {d{^ MaU {b{IE & (a) What is the primary productivity of an ecosystem and how is it expressed ? (b) Explain what does the equation given below show : 3 NPP = GPP R OR 15. (a) Name the type of detritus that decomposes faster. List any two factors that enhance the rate of decomposition. (b) Write the different steps taken in humification and mineralisation during the process of decomposition. (a) {Z Z{b{IV Ho$ A{^bjUm| H$s VwbZm H$s{OE (b) (a) (b) 57/3/1 : (i) n WwVmnr (`yarW_ b) VWm VZwVmnr ( Q>oZmoW_ b) Ord (ii) n WwbdUr (`yarh bmBZ) VWm VZwbdUr ( Q>oZmoh bmBZ) Ord Vw JVm ~r_mar Ho$ {V h_mam eara {H$g H$ma n` ZwHy${bV (Eop b_oQ>mB S>) hmo OmVm h ? Compare the characteristics of the following : (i) Eurythermal and Stenothermal organisms (ii) Euryhaline and Stenohaline organisms How does our body get acclimatized to altitude sickness ? 6 3 16. {dfmUw g H $_U H$s map ^H$ Ad Wm _| amoJ {ZXmZ H$s {H$ ht Xmo O d-amgm`{ZH$/Amp dH$ VarHo$ {b{IE & BZ_| go {H$gr EH$ Ho$ {g m V H$s `m `m H$s{OE & 3 AWdm 3 dm{hV _b Ho$ { Vr`H$ CnMma Ho$ Xm amZ AnZmE JE MaUm| H$m dU Z H$s{OE & Write any two biochemical/molecular diagnostic procedures for early detection of viral infection. Explain the principle of any one of them. OR Describe the steps that are followed during secondary treatment of sewage. 17. C ma ^maV _| IoVr Ho$ {bE nmXn OZH$ J o H$s Cn`w $ {H$ _| H $go {dH${gV (C n ) H$aVo h ? dh Bgo `m| H$aVo h ? 3 How did the plant breeders produce suitable varieties of sugarcane for cultivation in North India ? Why did they do it ? 18. 3 {H$gr nd Vr` jo Ho$ ^ _U Ho$ Xm amZ, Hw$N> ~ m| _| EobOu Ho$ bjU C n hmo JE h & (a) {H$ ht Xmo EobOu A{^bjUm| H$s gyMr ~ZmBE & (b) {H$ ht Xmo EobO Zm| Ho$ Zm_ {b{IE & (c) {H$ ht Xmo {VEobO Zm| (E|Q>rEobO g) H$s gyMr ~ZmBE & While on an excursion to a hill station, some of the children developed allergic symptoms. 19. (a) List any two allergic symptoms. (b) Name any two allergens. (c) List any two antiallergens. B b S> _| Am moJrH$aU Ho$ n MmV H$mbo dU (Jhao a J) dmbo eb^m| H$m mX ^m d mH ${VH$ daU mam {dH$mg H$m EH$ {Ma {Vp R>V CXmhaU h & `m `m H$s{OE & 3 Appearance of melanised moths post-industrialisation in England is a classic example of evolution by natural selection. Explain. 57/3/1 7 P.T.O. 20. _mZd OrZmo_ moOo Q> go m V _mZd OrZmo_ H$s H$moB N>: {deofVmE {b{IE & 3 Write any six salient features of the human genome as drawn from the human genome project. 21. {df_`w _H$Vm `m h ? S >mogmo{\$bm _| qbJ {ZYm aU H $_ H$s `m `m H$s{OE & 3 AWdm gwH|$ {H$`m| _| {df_m Jr H|$ H$s` Ama.EZ.E. (hnRNA) go nyU V: {H $`merb E_.Ama.EZ.E. (mRNA) Ho$ {Z_m U Ho$ H $_ H$s `m `m H$s{OE & H$mo{eH$m _| `h H $_ H$hm g n hmoVm h ? 3 What is heterogamety ? Explain the mechanism of sex determination in Drosophila. OR Explain the process of making heterogeneous nuclear RNA (hnRNA) into a fully functional mRNA in eukaryotes. Where does this process occur in the cell ? 22. 23. (a) {H$ ht Xmo H$ma Ho$ A V:J^m e`r `w{ $`m| (AmB .`y.S>r.) Ho$ Zm_ {b{IE VWm CZH$s {H $`m{d{Y H$s `m `m H$s{OE & (b) ghobr Zm_H$ Jmobr H$m J^ {ZamoYH$ Ho$ $n _| Cn`moJ H$aZo Ho$ bm^m| H$s gyMr ~ZmBE & (a) Name and explain the mode of action of any two types of IUDs. (b) List the advantages of using Saheli as a contraceptive. (a) EH$ OrdmUw H$mo gj_ `m| ~Zm`m OmE (b) O d- m mo{JH$s _| gy _-A V:jonU (_mBH $moB Oo eZ) VWm OrZ JZ H$s ^y{_H$m H$s `m `m H$s{OE & ? (a) Why should a bacterium be made competent ? (b) Explain the role of microinjection and gene gun in biotechnology. 57/3/1 8 3 3 24. EH$ Amd V~rOr nmXn Ho$ An[an d namJH$moe H$s AZw W-H$mQ> H$m AmaoI ~ZmBE & BgH$s {^{ m H$s {d{^ naVm| H$mo Zm_m {H$V H$s{OE VWm CZHo$ H$m` {b{IE & 3 Draw a T.S. of a young anther of an angiosperm. Label the different layers of the wall and write their functions. I S X SECTION D 25. (a) namJ- rHo$ga g H$f U _| d{V H$mJ H$s ^y{_H$m H$s `m `m H$s{OE & (b) Amd V~rOr nmXnm| _| { -H$moer` namJH$Um| go ma ^ H$a namJU-n M n[aKQ>ZmAm| H$m dU Z H$s{OE Omo Xmoham {ZfoMZ VH$ AJ gm[aV hmoVr h & 5 AWdm (a) { `m| _| gJ^ Vm Ho$ Xm amZ CZ n[aKQ>ZmAm| H$m C oI H$s{OE {OZgo Anam ( b g|Q>m) H$m {dH$mg hmoVm h & (b) gJ^ Vm Ho$ Xm amZ Anam ( b g|Q>m) H$s ^y{_H$m H$s `m `m H$s{OE VWm BgHo$ A V: mdr A J Ho$ $n _| H$m` H$aZo H$s ^r `m `m H$s{OE & (a) Explain the role of stigma in pollen-pistil interactions. (b) Describe the post-pollination events leading to double fertilization in angiosperms, starting with a two-celled pollen grain. 5 OR 26. (a) Mention the events that lead to the development of placenta during pregnancy in human females. (b) Explain the role of placenta during pregnancy including its action as an endocrine organ. (a) Amn H $go nVm bJmE Jo {H$ C mZ _Q>a H$m {X`m J`m b ~m nm Ym g_`w _Or (hmo_mo OmBJg) h AWdm {df_`w _Or (hoQ>oamo OmBJg) ? nZoQ> dJm] H$s ghm`Vm go AnZo C ma H$mo _m{UV H$s{OE & 57/3/1 9 P.T.O. (b) dV $n go H$amE JE Xmo EH$-g H$a H $m g Ho$ {Z Z{b{IV h : (i) 1:2:1 (ii) 3:1 F2-bjU $nr AZwnmV `oH$ AZwnmV `m Xem Vm h ? C oI H$s{OE & 5 AWdm (a) (b) AnZo `moJm| _| hf o Ed Mog Zo {d{H$aU-g{H $` (ao{S>`moEop Q>d) 32P VWm 35S H$m Cn`moJ `m| {H$`m ? `m `m H$s{OE & AnZo `moJm| go m V n[aUm_m| Ho$ AmYma na C hm|Zo `m {Z H$f {ZH$mbo Am a H $go ? (a) How would you find out whether a given tall garden pea plant is homozygous or heterozygous ? Substantiate your answer with the help of Punnett squares. (b) Given below are the F2-phenotypic ratios of two independently carried monohybrid crosses : (i) 1:2:1 (ii) 3:1 5 Mention what does each ratio suggest. OR 27. (a) Why did Hershey and Chase use radioactive 32P and 35S in their experiments ? Explain. (b) Following the experiments conducted by them, write what conclusion did they arrive at and how. (a) Cg OrZg b _mo{S>`_ H$m {d{e Q> Zm_ {b{IE Omo _Zw `m| _| A{V J ^ra amoJ H$m H$maH$ h & amoJ H$m Zm_ {b{IE & b _mo{S>`_ Ho$ OrdZ MH $ H$s CZ n[aKQ>ZmAm| H$m dU Z H$s{OE Omo _mXm EZmo\o$br O _| g n homVr h & O~ b _mo{S>`_ _mZd H$s bmb {Ya-H${UH$mAm| _| doe H$aVo h , Vmo CZ_| `m n[adV Z hmoVm h ? `m `m H$s{OE & _Zw ` Ho$ eara na BgH$m `m ^md n S>Vm h ? AWdm (b) (c) {H$ ht VrZ g_w{MV CXmhaUm| H$s ghm`Vm go H$m~ {ZH$-IoVr VWm O d-Cd aH$m| Ho$ ~rM nma n[aH$ g ~ Y H$s `m `m H$s{OE & 57/3/1 10 5 5 (a) Write the specific name of the genus Plasmodium that causes one of the most serious types of diseases in humans. Name the disease. (b) Describe the events in the life cycle of Plasmodium which take place in the female Anopheles. (c) Explain what happens in the RBCs of the humans when Plasmodium gains entry into them. How does the human body get affected ? OR Explain the interrelationship between organic farming and biofertilizers, with the help of any three suitable examples. 57/3/1 11 P.T.O.

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