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CBSE Class 12 Board Exam 2019 : Biology (Series 2)

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SET-1 H$moS> Z . Series BVM/2 Code No. amob Z . 57/2/1 narjmWu H$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 57/2/1 Maximum Marks : 70 1 P.T.O. gm_m ` {ZX}e : (i) Z-n _| Mma I S>m| _ o Hw$b 27 Z {XE JE h & g^r Z A{Zdm` h & (ii) I S> A _| Z g `m 1 go 5 A{V bKw-C mar` Z h , `oH$ Z 1 A H$ H$m h & (iii) I S> ~ _| Z g `m 6 go 12 bKw-C mar` Z H$ma I Ho$ h , `oH$ Z 2 A H$m| H$m h & (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$aZm h & (vii) Amd `H$VmZwgma, {M m| H$m aoIZ gm\$-gwWam Ed `Wmo{MV bo~b hmoZm Mm{hE & General Instructions : (i) There are a total of 27 questions and four sections in the question paper. All questions are compulsory. (ii) Section A contains questions number 1 to 5, very short-answer type questions of 1 mark each. (iii) Section B contains questions number 6 to 12, short-answer type I questions of 2 marks each. (iv) Section C contains questions number 13 to 24, short-answer type II questions of 3 marks each. (v) Section D contains questions number 25 to 27, long-answer type questions of 5 marks each. (vi) There is no overall choice in the question paper, however, an internal choice is provided in two questions of 1 mark, two questions of 2 marks, four questions of 3 marks and all the three questions of 5 marks. In these questions, an examinee is to attempt any one of the two given alternatives. (vii) Wherever necessary, the diagram drawn should be neat and properly labelled. 57/2/1 2 I S> A SECTION A 1. C d~oYZ (Eop Z`mog|Q>o{gg) na d Ym{ZH$ {V~ Y H$mo `m`mo{MV {g H$aZo Ho$ nj _| EH$ H$maU Xr{OE & 1 Give one reason to justify statutory ban on amniocentesis. 2. 1 {Z Z{b{IV Ho$ H$maU hmoZo dmbo _mZd AmZwd {eH$ {dH$ma H$m Zm_ {b{IE : (a) {H$gr nw f _| EH$ A{V[a $ (b) {H$gr r _| EH$ X-H $mo_mogmo_ X-H $mo_mogmo_ hmoZm H$m A^md hmoZm AWdm 1 ~VmBE AgwJw{UVm (E `w bm BS>r) H$m `m n[aUm_ hmoVm h & Name a human genetic disorder due to the following : (a) An additional X-chromosome in a male (b) Deletion of one X-chromosome in a female OR State what does aneuploidy lead to. 3. nm Ym| VWm m{U`m| go `oH$ H$m EH$-EH$ CXmhaU Xr{OE Omo Angmar {dH$mg X{e V H$aVo h & 1 Mention one example each from plants and animals exhibiting divergent evolution. 4. {H$ ht Xmo H$m{`H$ amoYm| (\$s{ O`mobm {OH$b ~ [a`g ) Ho$ Zm_ {b{IE Omo ghO {Vajm XmZ H$aVo h & AWdm {Z Z{b{IV \$gbm| H$s {H$ _m o _| go Xmo amoJ {VamoYr {H$ _m| H$m M`Z H$s{OE {h_{Jar, nygm Jm ad, nygm H$mo_b, nygm 57/2/1 3 : 1 1 A-4 P.T.O. Name any two physiological barriers that provide innate immunity. OR Select two disease resistant crop varieties from the list of crop varieties given below : Himgiri, Pusa Gaurav, Pusa Komal, Pusa A-4 5. n[a ` $ IoVm| _| H $bmoQ >mo{ng O gr IanVdma `m| \$bVr-\y$bVr h ? Xmo H$maU Xr{OE & 1 Give two reasons as to why a weed such a Calotropis flourishes in abandoned fields. I S> ~ SECTION B 6. _m g VWm _|T>H$ XmoZm| H$mo {ZfoMZ Ho$ {bE _m `_ Ho$ $n _| Ob H$s Amd `H$Vm hmoVr h & BZ XmoZm| Ordm| _| `w _H$-g b`Z H$hm g n hmoVm h Am a `h {H$g H$ma gw{Zp MV hmoVm h ? AWdm m{U`m| H$s A S> OH$ VWm gOrd OH$ lo{U`m| Ho$ EH$-EH$ CXmhaU XoVo h E C h| dJuH $V H$aZo H$m AmYma {b{IE & 2 2 Mosses and frogs both need water as a medium for fertilisation. Where does syngamy occur and how is it ensured in both these organisms ? OR Write the basis of categorising animals as oviparous or viviparous, giving one example of each. 7. (a) AmnH$mo Aa S> VWm go_ Ho$ ~rO {XE JE h & ^ yU-nmof H$m AdbmoH$Z H$aZo Ho$ {bE Amn BZ_| go {H$gH$m M`Z H$a|oJo ? (b) nm Ym| _| ^ yU-nmof H$m {dH$mg ^y U go nhbo hmoVm h & `m`g JVVm {g H$s{OE & (a) You are given castor and bean seeds. Which one of the two would you select to observe the endosperm ? (b) The development of endosperm precedes that of embryo in plants. Justify. 57/2/1 4 2 8. S>r.EZ.E. AUw H$s EH$ m Ibm _| 546 `yp b`moQ>mBS> g h & `{X Bg_| EoS>oZrZ `yp b`moQ>mBS >g H$s g `m 96 h , Vmo Cg_| Cnp WV gmBQ>mogrZ `yp b`moQ>mBS >g H$s g `m {H$VZr hmoJr ? 2 A segment of DNA molecule comprises of 546 nucleotides. How many cytosine nucleotides would be present in it if the number of adenine nucleotides is 96 ? 9. H$m{`H$ g H$aU {H$g H$ma {H$`m OmVm h ? H$m{`H$ g H$a H$m EH$ CXmhaU Xr{OE & 2 How is somatic hybridization carried out ? Mention one example of a somatic hybrid. 10. Oob d wV H$U-g MbZ (Oob-Bbo Q >mo\$moao{gg) Ho$ Xm amZ S>r.EZ.E. I S>m| H$s Cnp W{V H$m _mZgXe Z (Am^mg) {H$g H$ma {H$`m OmVm h ? jmbZ (BbyeZ) `m hmoVm h ? 2 How are DNA fragments visualised during gel-electrophoresis ? What is elution ? 11. _ Ho$ H$s IoVr H$aZo dmbm EH$ {H$gmZ AnZr \$gb _| _ H$m-^oXH$ nr S>H$ Ho$ AmH $_U H$s {MaH$m{bH$ g_ `m go nr{ S>V h & n`m daU Ho$ {V g doXZerb hmoZo Ho$ H$maU dh H$sQ>ZmeH$ H$m {N> S>H$md Zht H$aZm MmhVm & O d- m mo{JH$s Ho$ AnZo kmZ Ho$ AmYma na BgH$m g_mYmZ gwPmBE & Bgo m V H$aZo Ho$ {bE {H$E OmZo dmbo Cnm` Ho$ {d{^ MaU {b{IE & 2 A corn farmer has perennial problem of corn-borer infestation in his crop. Being environmentally conscious he does not want to spray insectides. Suggest solution based on your knowledge of biotechnology. Write the steps to be carried out to achieve it. 12. O_ Zr Ho$ H ${V{dX Abo O|S>a dm Z h ~mo Q> mam X{jUr A_o[aH$m Ho$ O Jbm| _| {H$E JE JhZ A dofU Ho$ g_` CZHo$ mam {H$E JE Xmo ojU {b{IE & AWdm `{X {H$gr N gmB O H$s g_p Q> _| O _-Xa H$mo b VWm _ `w-Xa H$mo d mam {Z ${nV {H$`m OmVm h , V~ BH$mB g_` Ad{Y t _| N _| d { AWdm mg {Z Z H$ma go hmoJm : 2 dN (b d ) N dt Cn`w $ g_rH$aU H$mo Bg H$ma ^r {Z ${nV H$a gH$Vo h : dN r N , {Og_| r = (b d) dt r `m {Z ${nV H$aVm h ? {H$gr g_p Q> Ho$ {bE {b{IE & 57/2/1 5 r H$m n[aH$bZ H$aZo H$m H$moB EH$ _h d 2 P.T.O. State two observations made by German naturalist, Alexender von Humboldt during his extensive explorations in South American jungles. OR If in a population of size N the birth rate is represented as b and the death rate as d , the increase or decrease in N during a unit time period t will be : dN (b d ) N dt The equation given above can also be represented as : dN r N , where r = (b d) dt What does r represent ? Write any one significance of calculating r for any population. I S> g SECTION C 13. nw nr nmXnm| _| Q>onrQ>_ Ed ghm` H$mo{eH$mE H$~ Am a H$hm C n hmoVr h ? CZHo$ H$m`m] H$m dU Z H$s{OE & AWdm EH$ Amd V~rOr Ho$ Za `w _H$moX{ ^X _| {Z Z{b{IV g aMZmE H$hm Cnp WV hmoVr h ? `oH$ Ho$ H$m` H$m C boI H$s{OE & (a) OZZ-{N> (b) nmoamonmobo{ZZ (c) OZZ H$mo{eH$m When and where do tapetum and synergids develop in flowering plants ? Mention their functions. OR 57/2/1 6 3 3 Where are the following structures present in a male gametophyte of an angiosperm ? Mention the function of each one of them. 14. (a) Germ pore (b) Sporopollenin (c) Generative cell 3 A S>OZZ n[aKQ>ZmAm| Ho$ C{MV AZwH $_ H$mo X{e V H$aZo Ho$ {bE EH$ dmh MmQ> ~ZmBE & Construct a flow chart exhibiting sequential events of oogenesis. 15. Kmg Ho$ ^y U H$s AZwX ` /AZw W-H$mQ> H$m AmaoI ~ZmH$a CgHo$ ^mJm| H$mo Zm_m {H$V H$s{OE & 3 AWdm nw f H$s ewH $OZH$ Z{bH$m H$s H$mQ> Ho$ AmaoIr` ` (Amd{Y V) H$m aoIm{M ~ZmBE VWm BgHo$ ^mJm| H$mo Zm_m {H$V H$s{OE & 3 Draw L.S. of an embryo of grass and label its parts. OR Draw a diagrammatic sectional view of a seminiferous tubule (enlarged) in humans and label its parts. 16. 17. (a) (b) C n[adV Z H $go K{Q>V hmoVo h ? {~ X C n[adV Z VWm \o $_{e Q> C n[adV Z _| A Va n > H$s{OE & (a) How does mutation occur ? (b) Differentiate between point mutation and frameshift mutation. 3 _ogo gZ VWm Q>mb mam AnZo `moJm| _| ZmBQ >moOZ Ho$ ^mar g_ Wm{ZH$ Ho$ Cn`moJ go `h {g hmo J`m {H$ S>r.EZ.E. AY -g ajr H$s Vah {VH ${V H$aVm h & `m `m H$s{OE {H$ do Bg {Z H$f na {H$g H$ma nh Mo & 3 AWdm EH$ Agr_Ho$ H$s Ho$ amB~mogmo_ _| hmoZo dmbo WmZm VaU ( $nm VaU) H$s {H $`m{d{Y H$s `m `m H$s{OE & 57/2/1 7 3 P.T.O. Use of heavy isotope of nitrogen by Meselson and Stahl demonstrated semi-conservative mode of replication of a DNA molecule. Explain how did they arrive at this conclusion. OR Explain the mechanism of translation that occurs in the ribosomes in a prokaryote. 18. S>m{d Z Ho$ mH ${VH$ daU Ho$ {g m V Ho$ AZwgma ZE Ord $nm| Ho$ Am{d^m d H$s Xa Ord Ho$ OrdZ-MH $ AWdm OrdZ-H$mb go g ~ h & EH$ CXmhaU H$s ghm`Vm go n Q> H$s{OE & 3 According to Darwinian theory of natural selection the rate of appearance of new forms is linked to the life-cycle or the life-span of an organism. Explain with the help of an example. 19. (a) `y_mo{Z`m VWm gm_m ` OwH$m_ Ho$ amoJH$maH$ Ordm| Ho$ Zm_ {b{IE & (b) BZ amoJm| Ho$ bjUm o _| `m A Va h (c) XmoZm| amoJm| Ho$ Xmo C^`{Z R> bjU {b{IE & ? 3 AWdm (a) _bo[a`m Ho$ amoJH$maH$ Ord Am a amoJdmhH$ Ord Ho$ d km{ZH$ Zm_ {b{IE VWm Bg amoJ Ho$ bjU {b{IE & (b) B {S>g nr. mam \ $bZo dmbo Xmo amoJm| Ho$ Zm_ {b{IE & (a) Name the causative agents of pneumonia and common cold. (b) How do these differ in their symptoms ? (c) Mention two symptoms common to both. OR (a) Write the scientific names of the causative agent and vector of malaria, and write its symptoms. (b) Name any two diseases spread by Aedes sp. 57/2/1 8 3 20. (a) (b) 21. A V: OZZ VWm ~{h: OZZ _| A Va n Q> H$s{OE & new OZZ (newnmbZ) _| A V: OZZ Ho$ H$moB VrZ bm^ VWm EH$ _h dnyU hm{Z {b{IE & (a) Differentiate between inbreeding and outbreeding. (b) List any three advantages and one important disadvantage of inbreeding practice in animal husbandry. O d- m mo{JH$s `moJembmAm| _| gdm {YH$ Cn`moJ {H$E OmZo dmbo ~m`mo[aEo Q>a H$m Zm_ {b{IE & Bg ~m`mo[aEo Q>a Ho$ A{Zdm` g KQ>H$m| H$m C oI H$s{OE {Oggo A{YH$ _m m _| dm {N>V C nmX nmZo Ho$ {bE g dY Z _m `_ H$mo AZwHy$bV_ n[ap W{V`m Cnb Y H$amB Om gH|$ & 3 3 Name the most commonly used bioreactor in biotechnology labs. Mention the most essential components this bioreactor must have so as to provide the optimum conditions to the culture medium, resulting in production of large volume of desired product. 22. EH$ {eew E.S>r.E.-A^md Ho$ gmW n Xm h Am h & (a) OrdZn` V Wm`r CnMma H$m EH$ g ^m ` VarH$m gwPmBE VWm CgH$s `m `m ^r H$s{OE & (b) Bg amoJ Ho$ {H$gr A ` g ^m ` CnMma H$m Zm_ {b{IE & 3 A child is born with ADA-deficiency. 23. (a) Suggest and explain a procedure for possible life-long (permanent) cure. (b) Name any other possible treatment for this disease. gmar (~ T>Vr) Am`w {na {_S> VWm p Wa Am`w {na {_S> _| A Va n > H$s{OE & AnZo C ma H$s AmaoIm| Ho$ gmW nwp Q> H$s{OE & 3 Differentiate between an Expanding age pyramid and a Stable age pyramid . Substantiate your answer with diagrams. 24. {H$gr {XE JE jo _| {dXoer Om{V`m| Ho$ AmH $_U Ho$ O d-{d{dYVm na ^md H$m {d bofU H$s{OE & Xmo CXmhaU ^r Xr{OE & 3 Analyse the effects of Alien species invasion on the biodiversity of a given area. Provide two examples. 57/2/1 9 P.T.O. I S X SECTION D 25. _|S>b Zo nrbo Ed Jmob ~rO dmbo g_`w _Or _Q>a Ho$ EH$ nm Yo H$m hao Ed PwauXma ~rO dmbo EH$ A ` _Q>a Ho$ nm Yo Ho$ gmW g H$aU {H$`m & CgZo nm`m {H$ F2-nr T>r H$s Hw$N> g_p Q>`m| _| OZH$ A{^bjUmo Ho$ ZE g `moOZ n[ab{jV hmo aho h & OZH$ nm Ym| Ho$ A{^bjUm| H$s F2-g V{V _| ZE g `moOZ Ho$ Am{d^m d H$s `m `m Amn {H$g H$ma H$a oJo ? nZoQ> dJ H$s ghm`Vm go AnZo C ma H$m g_W Z H$s{OE & AWdm Eg.Eb. {_ba Ho$ `moJ H$m dU Z H$s{OE & CZHo$ mam {H$E JE ojUm| VWm n dr na OrdZ H$s C n{ m Ho$ jo _| CZHo$ `moJXmZ na {Q> nUr H$s{OE & 5 5 Mendel crossed a homozygous pea plant having yellow and round seeds with another pea plant bearing green and wrinkled seeds. He found that in some of the F2 population new combination of parental characters were observed. How will you explain the appearance of a new combination of parental characters in F2-offsprings ? Support your answer with the help of Punnett square. OR Describe S.L. Miller s experiment. Comment on the observations he made and his contribution towards the origin of life on Earth. 26. (a) g{H $` {Vajm VWm {Zp H $` {Vajm _| A Va n > H$s{OE & (b) _mZd g_p Q> H$mo d W aIZo Ho$ {bE Q>rH$mH$aU Am a {VajrH$aU Ho$ `moJXmZ na {Q> nUr H$s{OE & AWdm eham| _| O{ZV `W Ob (dm{hV _b) H$mo mH ${VH$ Ob moVm| _| {dg{O V H$aZo go nhbo {H$E OmZo dmbo { Vr`H$ CnMma H$m dU Z H$s{OE & Bg H $_ mam hmoZo dmbo EH$ A ` bm^ H$m C oI H$s{OE & (a) (b) Differentiate between active and passive immunity. Comment on the role of vaccination and immunization in keeping human population healthy. OR Describe the process of secondary treatment given to municipal waste water (sewage) before it can be released into fresh waterbodies. Mention another benefit provided by this process. 57/2/1 10 5 5 27. ~ Jbw $ _| bmp Q>H$ H$s ~moar Ho$ C nmXZH$Vm Ah_X ImZ Zo bmp Q>H$ An{e Q> H$s g_ `m H$m EH$ AmXe hb Ty> T> {ZH$mbm & R>mog An{e Q> {ZnQ>mZ H$s MwZm {V`m| Ho$ g_mYmZ hoVw Ah_X ImZ mam {H$E JE `mgm o H$s `m `m nm M MaUm| _| H$s{OE & 1 5=5 AWdm (a) (b) nm[ap W{VH$ {na {_S> `m {Z ${nV H$aVo h ? BZ {na {_S>m| H$s {H$ ht Xmo gr_mAmo| H$m C oI H$s{OE & EH$ CXmhaU H$s ghm`Vm go O d-_m m Ho$ EH$ C Q>o {na {_S> H$m dU Z H$s{OE & 3+2=5 A plastic sack manufacturer in Bengaluru, Ahmed Khan has managed to find an ideal solution to the problem of plastic waste. Explain in five steps the efforts of Ahmed Khan to meet the challenges of solid waste management. OR (a) What does an ecological pyramid represent ? State any two limitations that these pyramids have. (b) Describe an inverted pyramid of biomass with the help of an example. 57/2/1 11 P.T.O.

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