CBSE Class 12 Biology Question Paper 2020 Set 57-2-3

H$moS> Z§.
Code No. 57/2/3
amob Z§. narjmWu H$moS >H$mo CÎma-nwpñVH$m Ho$ _wI-n¥ð
Roll No. >na Adí` {bIo§ &
Candidates must write the Code on the
title page of the answer-book.

ZmoQ> NOTE
(I) H¥$n`m Om±M H$a b| {H$ Bg àíZ-nÌ _o§ _w{ÐV (I) Please check that this question
n¥ð> 19 h¢ & paper contains 19 printed pages.

(II) àíZ-nÌ _| Xm{hZo hmW H$s Amoa {XE JE H$moS (II) Code number given on the right
>Zå~a H$mo N>mÌ CÎma-nwpñVH$m Ho$ _wI-n¥ð> na hand side of the question paper
{bI| & should be written on the title page of
the answer-book by the candidate.
(III) H¥$n`m Om±M H$a b| {H$ Bg àíZ-nÌ _| (III) Please check that this question
>27 àíZ h¢ & paper contains 27 questions.

(IV) H¥$n`m àíZ H$m CÎma {bIZm ewê$ H$aZo go (IV) Please write down the Serial
nhbo, CÎma-nwpñVH$m _| àíZ H$m H«$_m§H$ Number of the question in the
Adí` {bI| & answer-book before attempting it.
(V) Bg àíZ-nÌ H$mo n‹T>Zo Ho$ {bE 15 {_ZQ >H$m (V) 15 minute time has been allotted to
g_` {X`m J`m h¡ & àíZ-nÌ H$m {dVaU read this question paper. The
nydm©• _| 10.15 ~Oo {H$`m OmEJm & question paper will be distributed
10.15 ~Oo go 10.30 ~Oo VH$ N>mÌ Ho$db at 10.15 a.m. From 10.15 a.m. to
10.30 a.m., the students will
àíZ-nÌ H$mo n‹T>|Jo Am¡a Bg Ad{Y Ho$ Xm¡amZ read the question paper only and
do CÎma-nwpñVH$m na H$moB© CÎma Zht {bI|Jo & will not write any answer on the
answer-book during this period.

Ord {dkmZ (g¡ÕmpÝVH$)
BIOLOGY (Theory)

{ZYm©[aV g_` : 3 KÊQ>o A{YH$V_ A§H$ : 70
Time allowed : 3 hours Maximum Marks : 70

.57/2/3 1 P.T.O.

gm_mÝ` {ZX}e :
{ZåZ{b{IV {ZX}em| H$mo ~hþV gmdYmZr go n{‹T>E Am¡a CZH$m g™Vr go nmbZ H$s{OE :
(i) àíZ-nÌ nm±M IÊS>m| _§| {d^m{OV {H$`m J`m h¡  H$, I, J, K Am¡a L> &
(ii) Bg àíZ-nÌ _| 27 àíZ h¢ & g^r àíZ A{Zdm`© h¢ &
(iii) IÊS> H$ _| àíZ g§»`m 1 go 5 VH$ ~hþ{dH$ënr` àíZ h¢, àË`oH$ àíZ 1 A§H$ H$m h¡ &
(iv) IÊS> I _| àíZ g§»`m 6 go 12 VH$ bKw-CÎmar` àH$ma-I Ho$ àíZ h¢, àË`oH$ àíZ 2 A§H$m|
H$m h¡ &
(v) IÊS> J _| àíZ g§»`m 13 go 21 VH$ bKw-CÎmar` àH$ma-II Ho$ àíZ h¢, àË`oH$ àíZ
3 A§H$m| H$m h¡ &
(vi) IÊS> K _| àíZ g§»`m 22 go 24 VH$ bKw-CÎmar` àH$ma-III Ho$ àíZ h¢, àË`oH$ àíZ
3 A§H$m| H$m h¡ &
(vii) IÊS> L> _| àíZ g§»`m 25 go 27 VH$ XrK©-CÎmar` àíZ h¢, àË`oH$ àíZ 5 A§H$m| H$m h¡ &
(viii) CÎma g§{já VWm q~Xþdma hmoZo Mm{hE &
(ix) Bg àíZ-nÌ _| g_J« na H$moB© {dH$ën Zht h¡ & VWm{n EH$-EH$ A§H$ dmbo Xmo àíZm| _|,
Xmo-Xmo A§H$m| dmbo EH$ àíZ _§o, VrZ-VrZ A§H$m| dmbo Xmo àíZm| _§o Am¡a nm±M-nm±M A§H$m|
dmbo VrZm| àíZm| _§o Am§V[aH$ {dH$ën {XE JE h¢ & Eogo àíZm| _| Ho$db EH$ hr {dH$ën H$m
CÎma Xr{OE &
(x) Ohm± Amdí`H$ hmo, dhm± gmµ\$-gwWam, AmZwnm{VH$ VWm g_w{MV Zm_m§{H$V {MÌ ~ZmBE &
(xi) BgHo$ A{V[aº$, Amdí`H$VmZwgma, àË`oH$ IÊS> Am¡a àíZ Ho$ gmW `Wmo{MV {ZX}e {XE JE
h¢ &
IÊS> H$
ZmoQ> : {ZåZ{b{IV àíZm| _| àË`oH$ àíZ _| {XE JE {dH$ënm| go ghr {dH$ën MwZH$a {b{IE &
1. {ZåZ{b{IV _| go H$m¡Z-gm nmaOrdr à`moJm| H$m CËnmX Zht h¡ ? 1

(A) nr‹S>H$-n«{VamoYr µ\$gb H$s {H$ñ_
(B) ImÚmZm| _| Cƒ nm¡f{UH$ _mZ
(C) Ama.-S>r.EZ.E. VH$ZrH$ Ûmam B§gwbrZ H$m CËnmXZ
(D) Obm^md-à{VamoYr µ\$gb|
2. _mZdm| _| Q>mB\$m°BS> H$s nw{ï> hoVw {ZXmZmË_H$ narjU h¡ 1
(A) E{bgm
(B) {dS>mb
(C) E_.Ama.AmB©.
(D) Cë~doYZ
.57/2/3 2

General Instructions :
Read the following instructions very carefully and strictly follow them :
(i) Question paper comprises five sections – A, B, C, D and E.
(ii) There are 27 questions in the question paper. All questions are compulsory.
(iii) Section A – Questions no. 1 to 5 are multiple choice questions, carrying
1 mark each.
(iv) Section B – Questions no. 6 to 12 are short-answer questions type-I,
carrying 2 marks each.
(v) Section C – Questions no. 13 to 21 are short-answer questions type-II,
carrying 3 marks each.
(vi) Section D – Questions no. 22 to 24 are short-answer questions type-III,
carrying 3 marks each.
(vii) Section E – Questions no. 25 to 27 are long-answer questions, carrying
5 marks each.
(viii) Answers should be brief and to the point.
(ix) There is no overall choice in the question paper. However, an internal
choice has been provided in two questions of 1 mark, one question of
2 marks, two questions of 3 marks and three questions of 5 marks. Only
one of the choices in such questions have to be attempted.
(x) The diagrams drawn should be neat, proportionate and properly labelled,
wherever necessary.
(xi) In addition to this, separate instructions are given with each section and
question, wherever necessary.

SECTION A
Note : Choose the correct option from the choices given in each of the following
questions.

1. Which one of the following is not the product of transgenic experiments ? 1
(A) Pest-resistant crop variety
(B) High nutritional value in grains
(C) Production of insulin by rDNA technique
(D) Drought-resistant crops

2. The diagnostic test that confirms typhoid in humans is 1
(A) ELISA
(B) Widal
(C) MRI
(D) Amniocentesis
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3. O¡d-g{H«$` AUw {OgH$m Cn`moJ A§J à{VamonU Ho$ Xm¡amZ à{Vajm -{ZamoYH$ (Bå`yZmogàog|Q> )
Ho$ ê$n _| {H$`m OmVm h¡ 1

(A) Q>oQ´>mgmBŠbrZ
(B) gmBŠbmoñnmo[aZ-E
(C) ñQ>¡{Q>Z
(D) ñQ´>¡ßQ>mo_mBgrZ
AWdm
‘Zrbr H«$m§{V’ H$m Cn`moJ Bg g§X^© _| {H$`m OmVm h¡ 1

(A) Ob g§ajU hoVw ~m±Y ~ZmZm
(B) ~‹S>r _mÌm _| _Ëñ` CËnmXZ
(C) dm{hV _b H$m CnMma
(D) e¡dmb àñ\w$Q>Z (AëJb ãby_) H$m {Z`§ÌU

4. AZwÝ_rë` namJUr nwîn ñdnamJUr hmoVo h¢ Š`m|{H$ 1

(A) do C^`qbJr ({ÛqbJr) nwîn hmoVo h¢ Omo H$^r ^r AZmd¥V Zht hmoVo &
(B) do C^`qbJr ({ÛqbJr) VWm AZmd¥V nwîn hmoVo h¢ &
(C) do EH$qbJr hmoVo h¢ &
(D) namJH$moe Ho$ ñ\w$Q>Z go nhbo hr d{V©H$mJ« n[anŠd hmo OmVm h¡ &
AWdm
Bg_| Mb ~rOmUwAm| Ûmam Ab¢{JH$ àOZZ hmoVm h¡ 1

(A) no{Zgr{b`_
(B) hmBS´>m
(C) ñn§O
(D) Šb¡{_S>mo_moZmg

.57/2/3 4

3. The bioactive molecule used as an immunosuppressive agent during
organ transplant is 1

(A) Tetracyclin

(B) Cyclosporin-A

(C) Statin

(D) Streptomycin

OR

‘Blue revolution’ refers to 1

(A) construction of water dams for conservation of water

(B) production of fish in large quantities

(C) sewage treatment

(D) controlling algal bloom

4. Cleistogamous flowers are self-pollinated because 1

(A) they are bisexual flowers which do not open at all.

(B) they are bisexual and open flowers.

(C) they are unisexual.

(D) their stigma matures before the anthers dehisce.

OR

Asexual reproduction by zoospores is observed in 1

(A) Penicillium

(B) Hydra

(C) Sponge

(D) Chlamydomonas

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5. Hw$H$a{~Q²>g C^`qbJml`r nm¡Yo h¢ Š`m|{H$ 1
(A) `h EH$ hr nm¡Yo na Ho$db Za nwîn CËnÞ H$aVo h¢ &
(B) `h XmoZm| Za Ed§ _mXm nwîn EH$ hr nm¡Yo na CËnÞ H$aVo h¢ &
(C) `h C^`qbJr ({ÛqbJr) nwîn CËnÞ H$aVo h¢ &
(D) `h EH$ hr nm¡Yo na Ho$db _mXm nwîn CËnÞ H$aVo h¢ &
IÊS> I
6. XþX©_ A~w©X gwX_ A~w©X go {H$g àH$ma {^Þ h¢ ? Hw$N> amo{J`m| H$m CnMma -B§Q>a\o$am°Zm| go Š`m|
{H$`m OmVm h¡ ? 2

AWdm
Cg hm°_m}Z H$m Zm_ {b{IE Omo _ëQ>rnb Am¡ì`yboeZ E¡på~«`mo Q´>m§g \$a (MOET) VH$ZrH$
Ûmam Jm` H$mo {X`m OmVm h¡ & Bg hm°_m}Z H$m àH$m`© {b{IE & 2

7. _mZd eara _| ßbrhm Ho$ àH$m`© H$m C„oI H$s{OE & Bg_| CnpñWV Xmo {^Þ àH$ma H$s
H$mo{eH$mAm| Ho$ Zm_ {b{IE & 2

8. àË`oH$ H$m EH$-EH$ CXmhaU XoVo hþE ~VmBE {H$ d§emJ{V Ho$ {ZåZ{b{IV n¡Q>Z© H$mo Š`m H$hm
OmVm h¡ : 2
(a) EH$b OrZ EH$ go A{YH$ bjUàê$nr (\$sZmoQ>r{nH$) A{^ì`{º$ H$m {Z`§ÌU H$aVm
h¡ &
(b) EH$ bjUàê$nr bjU H$m {Z`§ÌU Xmo `m Xmo go A{YH$ OrZm| H$s ^mJrXmar Ûmam hmoVm
h¡ &
9. ZdOmV {eew H$mo _m± Ûmam àXmZ H$s OmZo dmbr à{Vajm Ho$ àH$ma H$m Zm_ {b{IE & `h
H¡$go hmoVr h¡ ? 2

10. _mZd _| (a) AY©gyÌmUw (AY©gyÌr H$mo{eH$m), VWm (b) `w½_H$m| _| gyÌJwUVm VWm JwUgyÌm| H$s
g§»`m {b{IE & 2

11. Cg d¡km{ZH$ H$m Zm_ {b{IE {OgZo _yb {gÕmÝV (g|Q´>b S>mo½_m) àñVwV {H$`m & BgH$s
ì`dñWmË_H$ àñVw{V Xr{OE & 2

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5. Cucurbits are monoecious plants as 1
(A) they produce only male flowers on the same plant.
(B) they produce both male and female flowers on the same plant.
(C) they produce bisexual flowers.
(D) they produce only female flowers on the same plant.

SECTION B

6. How are malignant tumours different from benign tumours ? Why are
some patients treated with -interferons ? 2

OR

Name the hormone with which a cow is administered using MOET
technology. State the function of this hormone. 2

7. Mention the function of the spleen in the human body. Name the two
different types of cells present in it. 2

8. State giving one example each, what are the following pattern of
inheritance called, where 2

(a) A single gene controls more than one phenotypic expression.

(b) Two, or more than two genes are involved in controlling a
phenotypic character.

9. Name the type of immunity the mother provides the newborn baby. How
does it happen ? 2

10. Write the ploidy and number of chromosomes in human (a) meiocytes,
and (b) gametes. 2

11. Name the scientist who proposed the Central Dogma. Give its schematic
representation. 2

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12. (a) ZrMo Xr JB© gyMr _| go {H$Ýht Xmo {eewYmZr àm{U`m| H$mo nhMmZ H$a {b{IE :
(i) bo_a
(ii) Yã~oXma H$ñH$g
(iii) C‹S>Z-\¡$boÝOa
(iv) ~m¡~H¡$Q>
(v) Vñ_m{Z`mB© ^o{‹S>`m
(vi) >N>Ny>±Xa

(b) ‘‘AmñQ´>o{b`m Ho$ {eewYmZr àm{U AZwHy$br {d{H$aU àX{e©V H$aVo h¢ &’’ H$WZ H$s
Ý`m`g§JVVm {gÕ H$s{OE & 2

IÊS> J
13. _¸$m Ho$ XmZo H$s I‹S>r (AZwàñW) H$mQ> H$m AmaoI ~ZmH$a BgHo$ ^«yUnmof, àm§Hw$a,
àm§Hw$a-Mmob, ñHw$Q>ob_, _ybm§Hw$a VWm _ybm§Hw$a-Mmob H$mo Zm_m§{H$V H$s{OE & 3

14. EH$ gm_mÝ` dU© (a§J) Ñ{ï> dmbr _{hbm {OgHo$ {nVm dUmªY Wo, EH$ gm_mÝ` dU© Ñ{ï> dmbo
nwéf go {ddmh H$aVr h¡ & Cggo OÝ_ boZo dmbr g§V{V Ho$ dU© g§doXr Ñ{ï> H$s g§^mì`Vm H$mo
Xem©Zo hoVw EH$ H«$m°g ~ZmBE & 3

15. d¡pídH$ ñVa na H$m~©Z H$m pñWarH$aU Ord_§S>b _| àH$me-g§íbofU Ho$ Ûmam hmoVm h¡ &
(a) {H$Ýht Eogo Xmo VarH$m| H$s ì`m»`m H$s{OE {OZHo$ Ûmam àmH¥${VH$ àH«$_m| Ûmam
dm`w_§S>b _| H$m~©Z H$s nwZamny{V© (dmngr) hmoVr h¡ &
(b) _mZd Ho$ Eogo H$moB© Xmo H$m`©H$bmnm| H$s gyMr ~ZmBE {OZgo àH¥${V _| H$m~©Z MH«$
à^m{dV hwAm hmo & 3

16. (a) EH$ nm[aV§Ì _| naOrdm| _§o {H$g àH$ma H$m AZwHy$bZ hþAm {H$ dh AnZo nanmofr Ho$
gmW gh-ApñVËd ~ZmE aI gH|$ & g_PmBE &
(b) naOrdr {d{eï> nanmofr na hr Am{lV hmoVo h¢ VWm gh-{dH${gV hmoVo h¢ & `{X
nanmofr naOrdr Ho$ à{V à{VamoYr AWdm AñdrH$ma H$aZo H$m VarH$m {dH${gV H$aVm
h¡, Vmo naOrdr {H$g àH$ma AZw{H«$`m H$aoJm ? 3

AWdm
.57/2/3 8

12. (a) Identify any two marsupials from the list given below :
(i) Lemur
(ii) Spotted cuscus
(iii) Flying phalanger
(iv) Bobcat
(v) Tasmanian wolf
(vi) Mole

(b) ‘‘Australian marsupials exhibit adaptive radiation.’’ Justify the
statement. 2

SECTION C

13. Draw a vertical section of maize grain and label its endosperm, plumule,
coleoptile, scutellum, radicle and coleorhiza. 3

14. A woman with normal colour vision, whose father was colourblind,
married a man with normal colour vision. Work out a cross to show the
probability of children born to them with respect to colour vision. 3

15. Global carbon is fixed in the biosphere through photosynthesis.

(a) Explain any two ways by which carbon is returned to the
atmosphere through natural processes.

(b) List any two human activities that have influenced the carbon
cycle in nature. 3

16. (a) Write how parasites have evolved with adaptation to co-exist with
their hosts in an ecosystem.

(b) Parasites are host specific and tend to co-evolve. How would the
parasite respond if the host evolves a certain mechanism to resist
or reject the parasite ? 3

OR
.57/2/3 9 P.T.O.

(a) {H$gr nm[aV§Ì _| nmE OmZo dmbo AmXe© {na¡{_S> H$m Zm_ {b{IE & BgH$mo Vrgao
nmofU ñVa VH$ ~ZmBE VWm CZHo$ Zm_ {b{IE &
(b) {H$gr nm[aV§Ì H$mo gy`© go 1,000,000 J gm¡a D$Om© àmá hmoVr h¡ & H«$_e: àW_ Ed§
Vrgao nmofr ñVa na CnbãY D$Om© H$s _mÌm {b{IE & 3

17. D$VH$ g§dY©Z Š`m h¡ ? Bg VH$ZrH$ Ûmam {dfmUw g§H«${_V Ho$bo Ho$ nm¡Yo go {dfmUw_wº$ ñdñW
Ho$bo Ho$ nm¡Yo {H$g àH$ma àmá {H$E Om gH$Vo h¢ ? ì`m»`m H$s{OE & 3

18. {XE JE {MÌ H$m AÜ``Z H$s{OE :

A EH$ ^«yUmdñWm h¡ Omo B _| ê$nmÝV[aV hmo OmVm h¡ VWm _mZd {ñÌ`m| Ho$ J^m©e` A§V:ñVa
_| A§Vam}{nV hmo OmVm h¡ &
(a) A, B VWm BgHo$ C Ed§ D ^mJm| H$mo nhMmZ H$a {b{IE &
(b) _mZdm| _| ^«yUr` n[adY©Z Ho$ Xm¡amZ H$mbmÝVa _| C VWm D H$m Š`m hmoVm h¡ ? 3

AWdm
(a) ZrMo {XE JE {MÌ H$mo nhMm{ZE VWm BgHo$ B, C, D Ed§ E Ho$ ^mJm| H$mo ^r nhMmZ
H$a {b{IE &

(b) E H$m àH$m`© ^r {b{IE & 3

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(a) Name an ideal pyramid existing in an ecosystem. Construct it up
to its three trophic levels along with their names.
(b) The sun provides 1,000,000 J of sunlight (solar energy) to an
ecosystem. Write the amount of energy that is available to the first
and third trophic levels, respectively. 3

17. What is tissue culture ? Explain how, from a virus infected banana plant,
virus free healthy banana plants can be grown by this technique. 3

18. Study the given diagram :

A is an embryonic stage that gets transformed into B, which in turn gets
implanted in the endometrium in human females.
(a) Identify A, B and its parts C and D.
(b) State the fate of C and D in the course of embryonic development
in humans. 3
OR
(a) Identify the figure given below and also identify the parts B, C, D
and E.

(b) State the function of E. 3

.57/2/3 11 P.T.O.

19. {H$gr nm[aV§Ì _| _yb AÝdofH$ àOm{V Ho$ EH$ Z½Z MÅ>mZ na AmH«$_U go àma§^ H$a
Ma_mdñWm g_wXm` VH$ Ho$ AZwH«$_U Ho$ {d{^Þ MaUm| H$m dU©Z H$s{OE & Bg àH$ma Ho$
AZwH«$_U H$m Zm_ {b{IE & 3

20. ZJam| Ho$ An{eï> Ob Ed§ Am¡Úmo{JH$ ~{h:òmd H$mo àmH¥${VH$ Ob òmoVm| _§o {Z_w©º$ H$aZo go
Obr` OrdZ na {dZmeH$mar (KmVH$) à^md n‹S> ahm h¡ & Bg ~{h:òmd H$mo àmH¥${VH$ Ob
òmoVm| _| {dg{O©V H$aZo go nhbo BgHo$ dm§{N>V O¡{dH$ CnMma H$s ì`m»`m H$s{OE & 3

21. ~¡grbg Wy[a¨{OE|{gg O~ EH$ {d{eï> H$sQ> Ho$ eara _| à{dï> hmoVm h¡, Vmo dh H$sQ> _a
OmVm h¡, naÝVw `h ñd`§ Aà^m{dV ahVm h¡ & g_PmBE {H$ `h {H$g àH$ma g§^d h¡ & 3

IÊS> K

22. (a) ZrMo Xr JB© nm°br_aoO ûm¥§Ibm A{^{H«$`m Ho$ MH«$ _| MaU A VWm B H$mo nhMmZ H$a
{b{IE & >

(b) MaU B _| Cn`moJ {H$E OmZo dmbo E§µOmB_ H$m {d{eï> A{^bjU {b{IE & 3

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19. Starting from the pioneer species, trace the sequence that follows in an
ecological succession on a bare rock, until climax community is reached in
an ecosystem. Name this type of succession. 3

20. The release of municipal wastewater and industrial waste into our
natural water bodies is causing disastrous effect to the aquatic life.
Explain the biological treatment that should be given to it before
releasing into the natural water bodies. 3

21. When Bacillus thuringiensis enters a certain insect’s body, the insect gets
killed, but itself remains unaffected. Explain how it is possible. 3

SECTION D

22. (a) Identify steps A and B in a cycle of Polymerase Chain Reaction
given below.

(b) State the specific characteristic feature of the enzyme in carrying
step B. 3

.57/2/3 13 P.T.O.

23. Eg.Eb. {_ba Ho$ à`moJ H$m AmaoIr` {Zê$nU ZrMo {X`m J`m h¡ & BgH$m AÜ``Z H$s{OE
VWm {ZåZ{b{IV àíZm| Ho$ CÎma Xr{OE :

BboŠQ´>moS>

~ÝX âbmñH$
d¡Š`y_ nån H$mo
J¡g|
Ob ~mha
g§K{ZÌ
Ob A§Xa
Ob {~ÝXþ

H$m~©{ZH$ `m¡{JH$m|
C~bVm Ob dmbm Ob
nme _| Ðd Ob

(a) Eg.Eb. {_ba Zo AnZo à`moJ g§`moOZ _§o CZ n[apñW{V`m| H$mo H¡$go CËnÞ {H$`m Omo
n¥Ïdr na OrdZ H$s CËn{Îm go nyd© _m¡OyX Wt ?

(b) CgHo$ à`moJ Ho$ A§V _§o ~ZZo dmbo H$m~©{ZH$ `m¡{JH$ H$m Zm_ {b{IE {Ogo CgZo àmá
(EH${ÌV) {H$`m &

(c) {dH$mg Ho$ Cg àH$ma H$m Zm_moëboI H$s{OE {OgH$m g_W©Z CgHo$ à`moJ Ûmam
hþAm & 3

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23. Study the diagrammatic representation of S.L. Miller’s experiment given
below and answer the questions that follow :

Electrodes

Closed flask
To vacuum
pump

Gases

Water out
Condenser

Water in
Water droplets

Water containing
Boiling water organic compounds
Liquid water in trap

(a) How did S.L. Miller create the conditions which existed before the
origin of any life on Earth ?

(b) Name the organic compound formed and collected at the end of his
experiment.

(c) Mention the kind of evolution his experiment supports. 3

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24.

D$na {XE JE ì`dñWmnH$ {Zê$nU H$m AÜ``Z H$s{OE VWm {ZåZ{b{IV àíZm| Ho$ CÎma
Xr{OE :
(a) Bg_| A H$mo nhMmZ H$a {b{IE &
(b) Bg_| D H$mo nhMmZ H$a {b{IE &
(c) `{X {XE JE g_` t na g_{ï> KZËd H$m _mZ Cn`w©º$ AmaoImZwgma N h¡, Vmo
g_w{MV g§Ho$Vm| H$m Cn`moJ H$aVo hþE t + 1 g_` na g_{ï> KZËd H$mo g_rH$aU Ho$
ê$n _| {b{IE & 3

IÊS> L>

25. (a) AnZo à`moJm| _| B.H$mobmB© na H$m`© H$aVo hþE _ogoëgZ VWm ñQ>mb Bg {ZîH$f© na
H¡$go nhþ±Mo {H$ S>r.EZ.E. à{VH¥${V`Z AY©g§ajr hmoVr h¡ ?
(b) nwînr nmXnm| _| S>r.EZ.E. à{VH¥${V`Z _§o Q>oba Ed§ CZHo$ gh`mo{J`m| Ho$ `moJXmZ H$s
ì`m»`m H$s{OE & 5
AWdm
(a) CZ MaUm| H$mo {b{IE {OZHo$ Ûmam Q>r-Ama.EZ.E. (A§VaU Ama.EZ.E.) H$m
Eo_rZmoEo{gbrH$aU hmoVm h¡ &
(b) Agr_Ho$ÝÐH$s Ordm| _| ñWmZm§VaU (ê$nm§VaU) Ho$ Xm¡amZ amB~mogmo_m| _| hmoZo dmbr
n[aKQ>ZmAm| H$s ì`m»`m H$s{OE & 5

.57/2/3 16

24.

Study the schematic representation given above and answer the following
questions :

(a) Identify A in it.

(b) Identify D in it.

(c) When the population density at time t is N as shown above, write
the population density at time t + 1 in the form of an equation
using appropriate symbols. 3

SECTION E

25. (a) How did Meselson and Stahl reach the conclusion that DNA
replication is semi-conservative while working with E. coli in their
experiment ?

(b) Explain the contribution of Taylor and his colleagues in DNA
replication in flowering plants. 5

OR

(a) Write the steps that lead to aminoacylation of tRNA in the cell.

(b) Explain the events that occur in ribosomes during translation in
prokaryotes. 5

.57/2/3 17 P.T.O.

26. {díd _| ha OJh àH¥${V _| nm[apñW{VH$ g§VwbZ ~ZmE aIZo Ho$ {bE O¡d{d{dYVm g§ajU Ho$
à{V AË`{YH$ qMVm h¡ & VrZ H$maU XoVo hþE BgH$s ì`m»`m H$s{OE & Eogo {d{^Þ Cnm`m| H$mo
{b{IE Omo h_mao Xoe _| ~mKm| H$s g_{ï> ~‹T>mZo _| ghm`H$ {gÕ hþE h¢ & 5

AWdm
EH$sH¥$V O¡d IoVr Š`m h¡ ? gmoZrnV, h[a`mUm Ho$ a_oe MÝÐ S>mJa Zm_H$ {H$gmZ Zo Bg
VarHo$ H$m à^mdembr T>§J go {H$g àH$ma Cn`moJ {H$`m {H$ dh eyÝ` An{eï> à~§YZ _|
g\$b ahm ? 5

27. (a) _mZd H$s ewH«$OZH$ Z{bH$m Ho$ AmaoIr` H$mQ> H$m {MÌ ~ZmBE & BgHo$ {H$Ýht N>:
^mJm| H$mo Zm_m§{H$V H$s{OE &
(b) ewH«$OZZ àH«$_ _| em{_b nr`yf J«§{W hm°_m}Zm| Ho$ Zm_ {b{IE VWm BZHo$ àH$m`m] H$m
C„oI H$s{OE & 5

AWdm
(a) AmB©.`y.S>r. H$mo EH$ à^mdr J^©{ZamoYH$ `w{º$ H$hm OmVm h¡ & gm_mÝ` ê$n go
gdm©{YH$ Cn`moJ H$s OmZo dmbr {H$Ýht Xmo AmB©.`y.S>r. `w{º$`m| Ho$ Zm_ {b{IE VWm
CZHo$ H$m`© H$aZo Ho$ VarH$m| H$mo {b{IE &
(b) {H$gr {ddm{hV X§n{V H$mo ~§Ü`H$aU H$s gbmh H$~ Xr OmVr h¡ ? Bgo H«$_e: EH$
nwéf VWm ñÌr _| {H$g àH$ma g§nÞ H$aVo h¢ ? 5

.57/2/3 18

26. There is a great concern all over the world to conserve biodiversity for
maintaining ecological balance in nature. Explain giving three reasons.
Write different ways that have helped in increasing tiger population in
our country. 5
OR
What is integrated organic farming ? How did Ramesh Chandra Dagar, a
farmer from Sonepat, Haryana effectively use this procedure and succeed
with zero waste ? 5

27. (a) Draw the sectional view of a seminiferous tubule of human. Label
its any six parts.
(b) Name the pituitary hormones involved in the process of
spermatogenesis. State their functions. 5
OR
(a) IUDs are said to be effective contraceptives. Name any two
commonly used IUDs and write the mode of their actions.
(b) When is sterilisation advised to married couples ? How is it carried
out in a human male and a female, respectively. 5

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