neet (national eligibility entrance test) full test - 6

SOLUTIONS s-55

NEET (NATIONAL ELIGIBILITY ENTRANCE TEST) Full Test - 6

ANSWER KEY

1 (c) 21 (b) 41 (d) 61 (a) 81 (b) 101 (a) 121 (c) 141 (a) 161 (b)

2 (d) 22 (c) 42 (b) 62 (b) 82 (d) 102 (d) 122 (d) 142 (d) 162 (d)

3 (a) 23 (a) 43 (b) 63 (d) 83 (c) 103 (d) 123 (c) 143 (a) 163 (c)

4 (a) 24 (d) 44 (b) 64 (a) 84 (C) 104 (b) 124 (a) 144 (c) 164 (d)

5 (b) 25 (a) 45 (b) 65 (b) 85 (d) 105 (a) 125 (c) 145 (d) 165 (a)

6 (c) 26 (b) 46 (a) 66 (b) 86 (c) 106 (c) 126 (b) 146 (a) 166 (d)

7 (d) 27 (c) 47 (b) 67 (d) 87 (c) 107 (a) 127 (d) 147 (c) 167 (d)

8 (b) 28 (d) 48 (c) 68 (a) 88 (a) 108 (c) 128 (b) 148 (c) 168 (a)

9 (a) 29 (d) 49 (d) 69 (b) 89 (a) 109 (c) 129 (c) 149 (c) 169 (d)

10 (b) 30 (c) 50 (b) 70 (d) 90 (d) 110 (d) 130 (c) 150 (a) 170 (d)

11 (c) 31 (d) 51 (c) 71 (a) 91 (b) 111 (b) 131 (C) 151 (b) 171 (a)

12 (d) 32 (a) 52 (d) 72 (b) 92 (a) 112 (b) 132 (e) 152ÿ(c) 172 lb)

13 (b) 33 (a) 53 (d) 73 (a) 93 (a) 113 (a) 133 (a) 153 (d) 173 (b)

14 (d) 34 (b) 54 (c) 74 (d) 94 (b) 114 (a) 134 (a) 154 (a) 174 (c)

15 (a) 35 (a) 55 (d) 75 (d) 95 (a) 115 (b) 135 (c) 155 (a) 175 (b)

16 (d) 36 (c) 56 (c) 76 (b) 96 (d) 116 (a) 136 (b) 156 (a) 176 (a)

17 (c) 37 (a) 57 (b) 77 (d) 97 (d) 117 (b) 137 (b) 157 (b) 177 (c)

18 (d) 38 (c) 58 (d) 78 (a) 98 (b) 118 (c) 138 (a) 158 (b) 178 (c)

19 (b) 39 (d) 59 (a) 79 (a) 99 (d) 119 (b) 139 (b) 159 (d) 179 (b)

20 (b) 40 (a) 60 (b) 80 (c) 100 (b) 120 (c) 140 (a) 160 (c) 180 (d)

3.

4.

(c)

(d)

SECTION 1 -PHYSICS

HINTS & SOLUTIONS

ÿ ÿnow t|iatÿ

Angular displacement has unit(degree or radian) but it is dimensionless.

Note : vice-versa is not possible.The maximum acceleration will be

represented by line having maximum slope.Line BC represents maximum slope.Here change in velocity (Av)= 60-30 = 30m/s

Time interval (At) = 40-10 = 30s

acceleration (a)=Av 30 7- = - = lm/s"

.

At 30

(a)

(a)

AQ = AE t- AW = 100 + 300 = 400 J

Energy stored per unit volume,

E= -x stress x strain2

stress . stress

Y =-- or stram = ---strain

- x stress x -2

stress

V

Y

! Y

(b)

(c)

x = -gt"

- - x 9.8 x -x

2 2 2

1 9.8m

Control rods are made of cadmium

(d) L a n2, where n is number of turn per unitlength.

(b) The internal resistance of a cell is theresistance of electrolyte used in cell becauseit is the electrolyte which is responsible for

conduction of electricity inside the cell

CONCEPTREE Learning (An IIT Alumini Initiative) of 11

s-56 Target NEET

9. (a) T, = m(g + a); T, = m(g a):

t,-t2

T->

10. (b) T, is maximum in case (b).

11. (c) Potential over each capacitor = 200 voltCharge on each Capacitor

= 25x10 & x200 = 5x10 ° coulomb

h12. (d) For de-Broglie wavelength, X =-

rnv

So, if mv is doubled, value of X will behalved.

13. (b) We know that x = - [rate of change ofdt

momentum]Thus when torque acts on a body itsangular momentum changes.

14. (d) The minimum energy required for theemission of electrons is called work function

15. (a) We know that,Q = AE + work done by gasWork done by gas = Q - AEWork done by gas is maximum when AE isminimum, For isothermal change AE = 0. Sofor isothermal expansion work done ismaximum.

16. (d) mg - T = ma,

mt

T 3 1 ggiven, T = - mg ÿ=> - mg = ma=>a=ÿ

i7. (od' d/3 d

No. of

f

ringes =1/3

p 81XD

19. (b) Maximum capacity of currents in 40 W

40 2= -=- = 1

.82 A

220 11

Maximum capacity of current in 100 W

.00 5 .....= -= -= 0

.454A

220 11

Resistances of bulbs are

220x220 _ J20q & 220x220 =4g4Q

40 100

Now when they are joined in series with400 volt.

Current400

20.

= 0.236

1210 + 484

As current 0,236 A is more than max.

capacity of 40 W bulb so, this bulb willfuse.

(b) Work done at constant pressure

P(V2-V,) = nR (T, -T,)

T2 2V TiFrom

V,=>

21.

22.

(b)

(c)

24. (d)

=> r,=2xT

1-

-

-2x300 = 600

Work done = nR (T, -T,)= 0

.1x2 x (600-300) = 60 cal

(.ir- 1 = tan X X = 45°

, angle of friction= angle of repose

s = (5 x 10~3

)(1 / 0.1) = 0.05 V .

Satellite

The weightlessness in a satellite is due tothe fact that the normal reaction on a bodyon its surface is zero.

The forces acting on anobject in the satellite are(i) gravitational attraction due to earth,

GMm

Fr-?r(towards the earth)(ii) normal reaction, N (away from the earth)Also, the object has a centripetalacceleration a, given by

GM

By Newton's third law,


SOLUTIONS s-57

F0

GMm „ (GM)

- Ml | - I

- N = ma

N = m

25. (a)

a2

A) + A2

A2 - A,

3ÿ

4

* max (A,+A2r 49

1

'max . 'min

28. (d) Power supplied =t

mgh 100Power used by crane = -X"ÿT} t 80

1000x10x100 100 103--x-- =-W

3600 80 36x8

29. (d) Escape velocity

r

=> N-0

Therefore, the apparent weight of the objectis zero.

11=

AJ2I2

"

16'12 a22

[A, & A, are amplitudes of waves]

(A2 - A|)

49:1

26. (b) The modulated voitage comprises of

(i) carrier wave of frequency coc

(ii) lower side frequency (oDc-coni) wave

(iii) upper side frequency (oc +com) waveThus in at AM wave information is

contained in lower (coc -com) and upper

(coc +rom)side frequencies.

27. (c) The current in an ac circuit is said to bewattless, if the power loss in the circuit iszero, i.e.,P = VI cos 9 = 0

which givescos0 = O rÿ0 = 9O°

mgh

v =

2 GM

R

2G(6 M)2 R

= VJ 2GM

R

v =V3vp V e

30. (c) Touque (t) on the triangle = M X Bt = iAB (since M = iA)

VI,t = i -(.f.sin 60 B = -

2 2f2.- -B

V3Bi

31. (d) Since v is doubled by increasing the

13 KTtemp, so by vrms = /-

, the temp.

increase by four times.

m

ToNow for constant pressure --

T,

V,=V, T|=T°K, T2=4T°K, V2= ?V

2=4V

32. (a) Sky appears blue because of scattering oflight when white light falls on the dustparticle of air it is scattered back to the earth.Since, blue light scatters most, it enters oureyes after scattering .So sky appears blue.

33. (a) The resonant frequency

i

fr ~

2n\l LC

ÿ=> I0& =-

27In/i0x10-°xC1

-3 .

ÿ c4n2 xlOxlO"5 xlO'2

= 2.5 x 10-,2F = 2.5pF

34. (b) Change in momentum = F X t= 10 x 10 = 100 Ns or 100 kg m/s

F£35. (a) A =

AY

6.28x10 x(l)

n(0.01)2 x2xlOn 1000


s-58 TargetNEET

36. (c) Energy of simple harmonic motion oc a

37. (a) In S.I. units, we have B = n(l (H +1)

38. (c) Vertical distance covered by water beforestriking ground = (H - h). Time taken is,

t = ÿ2(\{ -h)/g : Horizontal velocity of

SECTION 2 -CHEMISTRY

water coming out of hole at P, u = ÿ2 gh .Horizontal range

= ut = 72gh xÿ/2(H-h)/g

= 2A/h(H-h)

39. (d) P'

>,

M

Fish inside water will see point P at p, asexplained in the figure

MP, 4Here-= u = -

MP 3

MP, 4 4-= -=> MP'= 24x -= 32cm24 3 3

above the surface of water.

41. (d) P = p>1 orIc>Ib"

h

46. (a) As we move down in groups 13,14 and 15,inertness ofs2 electrons of valence shell

increases (inert pair effect). Thus in metalspresent at the bottom of the groups 13, 14,and 15 lower oxidation state becomes more

important, viz. Pb (+2 state rather +4), Bi(+3 state rather -i 5) and Ti (+1 rather than+3).

47 (b) Since each SrM ion provides one cationvacancy, henceConcentration of cation vacancies

= mole%ofSrCU added = I(H mole%

48.

49.

42. (b) Logic gates are fundamental units of digitalsystem.

43. (b) The forbidden energy gap for germanium 51.crystal is 0.71 eV.

44. (b) In intrinsic semi conductor, the number ofholes are equal to number of electrons i.e.,

V=fe

45. (b) Forward bais opposes the potential barrierand if the applied voltage is more than kneevoltage it cancels the potential barrier

10

100-x 6.023 x 1023 = 6

.

023xl0'7

(c)

(d)

CH3 - O - C3H7 and C2H5 - O - C2H5are metamers

The sulphide ore is roasted to oxide beforereduction because the AG1/ of most of the

sulphides are greater than those of CS? andH,S, therefore neither C nor H can reduce

metal sulphide to metal. Further, the standardfree energies of formation of oxide are muchless than those of SO,. Hence oxidation of

metal sulphides to metal oxide isthermodynamically favourable.

50. (b) By Freundlich adsorption isotherm :

= k(P)

M ™ =n,°gP + 1°gkCompare with y = mx + c

slope = tan 0 = tan 45° = 1

n=l and logk = 0.3010 = log2

mlog - = log (0.2)+log2

log| - | = log 0.4

±U0Am I

(c) H,S04 is a strong acid hence pH < 7 , or[H]" > 10 7, the aqueous solution of NaCIis neutral hence pH » 7 or [H+] a 10~7.The aqueous solution of NaNO, will bebasic hence pH > 7 or [H+] < 10 rH,S is a weak acid. Therefore, the correctorder will be

0.01 MNaNCX, <0.01 MNaCKO.Ol MH,S

<o.

oimh,s6,


SOLUTIONS s-59

53. (d) C,H5I and C,HsOH form non-ideal solution.54. (c) Cu21 forms complexes with the same

magnetic moment and geometryirrespective of the nature of ligand. It canbe explained by electronic configuration.

3d

Cu 11 11 11 11 1

It has 9 electrons in 3d shell. Hence anyincoming ligand whether it is strong orweak will result in the formation of same

geometry (if number of ligands is same)because any ligand can do nothing withthis unpaired e in 3d shell. Moreover, thecomplex formed will have same magneticmoment due to this unpaired e .

3 2 2 3 2sp sp sp up sp sp sp

55. (d) CH3CH = CHCH2-CH-C = CH

56. (c) AH =-2.5x102cal

AS = 7.4cal

AG = AH - TAS

= -2.5 x 103 -298x7.4 =-4705.2

.AG = - ive; so process is spontaneous

AG =0, Equilibrium

AG = ~ ive; Non-spontaneous

57. (b) BeO < MgO < CaO < BaOThe basic character of the oxides increases

down the group.Among these BeO is amphoteric.

4 =

>Cu

58. (d) I Lofl MCuSO, = 1 rnolofCu2+Cu2+ + 2e~

2 F of electricity will convert dil Cu2' intoCu

, hence [CuS04] = 0Thus, (d)

59. (a) (Na-,0., + HCI) is commercially known asoxone and is used for bleaching of delicatefibres.

60. (b) M(OH)xÿ ;M2+ + xOH~S xS

(S)(xS)X = K,sp

\\SV; - 4 . 10-,2

xMIOÿfÿx 10"12x=2

61. (a) On increasing temperature adsorption of agas on surface of solid decreases. Solidadsorb greater amount of substances atlower temperature.

62. (b) In the structure of ice each molecule of H-,0is surrounded by three H70 molecules inhexagonal honey comb manner. On theother hand in water, each molecule is

surrounded by four neighbouringmolecules randomly which results an opencage like structure. As a result there are anumber of'hole' or open spaces. In such astructure lesser number of molecules are

packed per ml. When ice melts a large no.of hydrogen bonds are broken. Themolecules therefore move into the holes or

open spaces and come closer to each otherthan they were in solid state. This resultsharp increase in the density. Therefore icehas lower density than water.

63. (d) The boiling point of o-nitrophenol is lessthan para-nitrophenol due to presence ofintramolecular hydrogen bonding. Sincep-nitrophenol is less volatile in than o-nitrophenol due to presence of intermolecular hydrogen bonding hence theycan be separated by steam distillation.

O

64. (a) R- C -R, HCN

K.CN

OHI

-> R -C-CN

Reduction by-»R

R'(A)

OHI

- c-ch2nh2IR'

sp

UAIH4(B)

65. (b) The species having minimum value of K,

will get precipitated first of all because ionicproduct will exceed the solubility productof such a species.The K value is minimum for BaS04( 10",1),so, BaS04 will get precipitated first of all.

66. (b) The ionic radii of trivalent lanthanidesdecreases progressively with increase inatomic number. This decrease is known as

lanthanide contraction.

67. (d) Number of atoms per unit cell = 1Atoms touch each other along edges.

Hence r= -2

(r = radius of atom and a = edge length)4

Therefore % fraction _ 3V

(2r)=-=0

.52


s-60 Target NEET

68. (a) Chlorodiaquatriamminecobalt(llI)chloride

is [CoCI(NH3)3(H20)2]Cl269. (b) Organometallic compounds are those

compounds in which there is a bond whichinvolve metal. In chlorophyll there is bondinvolving metal Mg

70. (d) Reaction (11) and reverse of reaction (1) givesthe desired reaction hence

K = K2x-

71. (a)

1 _

K2K,

~

K, ,2R ÿ- CI + Ag2ÿ ÿ

ether

O - R + 2AgCl 4-

72. (b) C2H5:MgBr|+H2C-CH2

1

74.

75.

CM LCI CI I,I "

1,0C2H5CH2CII2OM

n-buuino!

73. (a)

(d)

(d)

76. (b)

OMgBr

Standard electrode potential i.e. reductionpotential of A is minimum (-3.05 V) i.e. itsoxidation potential is maximum whichimplies 'A, is maximum reactive chemically.Na:C03 + Ca(OH), 2NaOH + CaC03Benzyl chloride (Cb

H5CH-,Cl) is more

reactive than vinyl chloride (CH0 = CHC1)Since the gas expands adiabatically (i.e.,no change in enthalpy) so the heat is totallyconverted into work.

For the gas, Cv = 20 J/K. Thus, 20 J of heatis required for 1 ° change in temperature ofthe gas.Heat change involved during the processi.e., work done = 3 kJ = 3000 J.

3000Change in temperature

20K = 150 K

77. (d)

78. (a)

Initial temperature = 300 KSince, the gas expands so the temperaturedecreases and thus final temperature is

300-150= 150

Chemically borax is sodium tetraboratedecahydrate and it has the formulaNa2B407.10H20.The acidity of acetylene or 1-alkynes canbe explained on the basis of molecularorbital concept according to whichformation of C-H bond in acetylene

involves sp-hybridised carbon atom. Nowsince s electrons are closer to the nucleus

than p electrons, the electrons present in abond having more s character will becorrespondingly more closer to the nucleus.Thus owing to high s character of theC-H bond in alkynes (s = 50%), the

electrons constituting this bond are morestrongly held by the carbon nucleus (i.e.,the acetylenic carbon atom or the sp orbitalacts as more electronegative species thanthe sp2 and sp3 with the result thehydrogen present on such a carbon atom(=C-H) can be esily removed as a proton.

79. (a) AH° = AHj'-(products)-AH)-(reactants)

AH° = AHf (HS) + AH? (H) - AH? (H2S)

x, =x(?) + x3-x2

.

-

. x = (x1+x2-x3)Thus, (a)

80. (c) K =[Ag"J[Cl]1.8 x 10~'10 = [Ag+] [0.1]

[Ag+1= 1.8 x 10~9MK =[Pb+2] [CI-]51

.7 x 10"5 = [Pb+2j [0.1 ]2[Pb+2]= 1.7 x 10ÿM

82. (d) Be shows diagonal relationship with A183. (c) Cr O F~ Na+

Electrons 9 8 10 10

Nuclear charge 8 8 9 11As greater the effective nuclear charge, moreis the attraction of nucleus towards

electrons hence higher will be the electronaffinity. Thus, Na

"

has higher E.A. than F~and other two. Similarly, F

~

has higher E.Athan O and O. Among O and O, Cr haslower E.A. value than O due to its greatersize. As greater the atomic radius of theatom less will be the attraction of the

nucleus to electron added and hence, lowerwill be the value of E.A. Thus, the correct

order of electron affinity isO" < O < F~ < Nat"

84. (c) 2CI(g)->Cl2(g)Entropy is decreasing (-ve) in the reaction.Further the reaction is exothermic since a

bond is being formed, i.e., AH is also -ve.

86. (c) CH3C1+A1C13-Electrophile

CH3++A1C14-


SOLUTIONS s-6I

87. (c) Reactions which involve absorption of heat 92. (a) Rafflesia or Corpse flower is a total rootenergy are called endothermic reactions. For parasite.

It obtains the total nourishment

such reactions. from ÿe root of the host plant. Its flowersV LI n. V* LJ

p only come out of the host plant and theyIn graphs (c) and (cl), the heat of products , . c, , ÿ .

,,

& r V V have a diameter ot I m and weight aroundis more than heat of reactants and thus they

represent endothermic reactions. But in (d)10 kg.

only small amount of energy is absorbed 94. (b) Algae Spirulina is one of the richest(less difference between energy of reactants sources of protein, containing 40-50and products). Thus, (c) represents percent crude protein on dry weight basismaximum activation energy. which under favourable condition mayNote: Activation energy is the excess energy reach upt0 70 percent. So, the peoplethat the reactant molecule must possess to recovering from long illness are advised tocross energy barrier. .

. take it in the diet.

88. (a) Mg, Ca, Sr, Ba. As the size increases, theionisation potential decreases. 95. (a) Single cotyledon of embryo in cereal grain

89. (a) Addition of monomers follows isoprene is represented by scutellum. Coleoptilerule represent the covering of stem. Coleorrhiza

represents the covering of root.

96. (d) Tracheids are chief water conducting

elements of xylern in gymnosperms. Theyare devoid of protoplasm and hence dead.

H T H T The wall constituting the tracheids is hard,

ÿ thick and lignified. These are elongated cellswith tapering ends.

CH3 98. (b) Mitosis is the process in which eukaryoticI | cell separates the chromosomes in its cell

C-CH2-C - CH2 j\s\s\t nucleus, into two identical sets in two

ÿ daughter nuclei. It is generally followed3 ' 3 immediately by cytokinesis, which divides

the nuclei, cytoplasm, organelles and cellmembrane into two daughter cellscontaining roughly equal shares of these

At. wt. , At. wt.

90. (d) At cathodes : Fe +2e -»Fe

Fe3+ + 3e~->Fe

(£ ÿ a At- Wt- . (Et,e)/ = cellular components. Mitosis and

2 3 cytokinesis together define the mitotic (M)(Ef„), 3 phase of the cell cycle - the division of the

Hence ----- - -'

(EFe)i 2 mother cell into two daughter cells,genetically identical to each other and to

-

SECTION 3-BOTANY- their parent cell.

91. (b) There are several factors and processes ÿ (d) In bivalent formation of chromosomeswhich differentiate living beings with non- during meiosiSi ,he homo|ogousliving beings like reproduction, respiration, chromosomes are arranged in pairs. Thegrowth, etc. But among them reproduction phenomenon is called synapsis and it occursis the only difference which differentiate durjng zygQtene stagg DÿA replicationwithout any exception living being withnon-living beings

occurs during S phase or synthetic phase

which is the second phase of interphase.


s-62 Target NEET

102. (d) Each pollen has two layered wall. The outerlayer is thick, tough, cuticularised called

exine which is composed of a material called"spoiMpjlicnin". It is highly resistant tohinlno-cai und nhvsical decomposition

. due

ÿrj i ÿ

.

to which pollens are preserved for a longtime in fossils.

103. (d) Silicosis is caused by exposure to dustcontaining silica.

104. (b) Cloning is a technique by which geneticallysame individuals can be produced withoutincluding any sexual reproduction e.g.

Dolly sheep.

105. (a) Polyembryony refers to the formation of

more than one embryo within a seed of aflowering plant, e g. Citrus.

106. (c) Desert show maximum difference between

day and night temperature.

107. (a) Population is an aggregation or groupingof individuals of the same species at thesame time in a particular area. Species is agrouping of individuals of one or morepopulations resembling each other inimportant morphological, anatomical andbiochemical characters and can potentiallyinterbreed. Biotic community is an

assemblage of interdependent, and

ecosystem is a self sufficient and self

regulating segment of nature comprisingof a biotic community and its physicalenvironment, both interacting andexchanging materials. The basic level ofecological organisation starts with theindividual, the next more complex levels arepopulations, species, community and thenecosystem.

110. (d) A solution having more solutes ascompared to solution having less numberof solutes. Former is known as hypertonicand later hypotonic. Hence, solution out

side the cytoplasm has more solutes(higher concentration) and are hypertonic.If two solutions have same solute

concentration then they are isotonic.

111. (b) The mitochondrial inner membrane forms

mfoldings known as cristae, which allow

greater surface area for protein such as cy-

tochrome to function properly and effi-

ciently.

112. (b) The essential elements are divided into

macroelements and microelements based

on the quantity in which they are required

by the plants. Mn. Fe, Cu, Mo, Zn, B, and

CI Tire the micronutrients needed in very

small quantities by the plants. C, H. O, N,P

, S, K, Ca, Mg, Fe are the macronutrients

required in more quantity.

113. (a) During sodium-potassium pump, theconcentration of sodium ions will be about

14 times more in extra cellular fluid (outside)

and concentration of potassium ions will

be about 28-30 times more in axoplasm(inside). Thus, 3Na+ and 2K+ are

transported during the process.

115. (b) In eukaryotic cells, two cytoplasmic

organelles, mitochondria and chloroplast

of green plants, contain their own geneticmaterials.

116. (a) Gibber!lie acid stimulates cell growth of

leaves and stem causing their expansion.

elongation respectively and leaf fall is con-trolled by ABA.

117. (b) A cross of Fj hybrid with its recessivehomozygous parent is called the test cross.

It is done to determine the genotype of agiven plant. If the given plant has

homozygous dominant traits then on test

cross it gives all dominant trait plants but if

it is heterozygous dominant than it gives

dominant and recessive phenotypes in 1 : 1ratio.

118. (c) The term "hot spots" was used by Benzerfor the sites which are more mutable than

other sites. Studies in 1978 revealed that 5-

methylcytosine residues occur at the

position of each hot spot.


SOLUTIONS s-63

119. (b) Pleiotropy is the condition in which a single

gene influences more than one trait.

Polyploidy is a condition in whichindividuals have more than two completesets of chromosomes.

Apomixis is a reproductive process in plantsthat superficially resembles normal sexualreproduction but there is no fusion ofgametes.

120. (c) Some plants growing in salty marshesdevelop special roots for respiration, calledpneumatophores. They are (-)velygeotropic.

121. (c) An RNA molecule whose base sequence iscomplementary to that of the RNAtranscript of a gene, i.e. the sense RNA,such as a messenger RNA (m RNA). Hence,an antisense RNA can undergo base pairingwith its complementary mRNA sequence.This blocks gene expression, either bypreventing access for ribosome to translatethe mRNA or by triggering degradation ofthe double stranded RNA by ribonucleaseenzymes. Antisense RNA and DNA both

have therapeutic potential for modifying theactivity of disease causing genes.

122. (d) Enzymes accelerate chemical reaction bylowering the activation energy.

123. (c) Competitive inhibition is the reversibleinhibition of enzyme activity due topresence of substrate analogues. Non

competitive inhibition is the reduction ofenzyme activity by a factor that has noreal structural similarity with the substrate.Allosteric inhibition is reversible

noncompetitive inhibition occurring incase of allosteric enzymes , Herein the

inhibitors are the products or intermediatesof reactions catalyzed by the enzymes.

Hence it is also called end productinhibition or feedback inhibition.

127. (d) Lecithin is a fat like substance called a phos-pholipid, which is a part of plasma mem-

brane.

128. (b) In this technique nematode spec fic genesare introduced in the host plant in such a

way that it produces both sense andantisense RNA. The two RNA

,

s being

complementary to each other form a doublestranded RNA (dsRNA) which is also called

interfering RNA responsible for initiatingRNA interference (RNA i) This (dsRNA)

bind to and prevent translation of specificmRNA of nematode (gene silencing). Thustransgenic plants based on RNAitechnology are resistant to nematode.

129. (c) During the process of replication the enzymethat helps to cut one strand of DNA duplexto release the tension of coiling of twostrands is topo-isomerase.

130. (c) A fed batch is a biotechnological batchprocess which is based on feeding of agrowth limiting nutrient substrate to culture.It is done for purifying enzymes.

131. (c) Gibberellins induces elongation of intern-odes.

133. (a) RNA interference technique, sense &antisense RNA fused to form dsRNA that

silent the expression of m- RNA ofnematode. RNA interference is a novel

strategy adopted to prevent infestation ofnematode Meloidegyrte incognitia in rootsof tobacco plants.

_

SECTION 4 -ZOOLOGY_

136. (b) While working at the Rockefeller Institute,Brown reported isolation of a PPLO fromhuman arthritic joint tissue in 1938.

In discussing the significance of thisobservation, Brown reported successfultreatment of arthritic patients in 1949 with anew antibiotic called aureomycin

143. (a) When water is not available, the camels

produce dry faeces and concentrated urine.One of the best sources of metabolic water

in camels is oxidation of food in the hump.

146. (a) Gamete intrafallopian transfer (GIFT) isrecommended for those females who

cannot produce an ovum. In this process,


s-64 Target NEET

the eggs of the donor woman are removedand in a form of mixture with spermtransferred into fallopian tube of anotherwoman who cannot produce ovum, but can

provide suitable environment forfertilization. Thus in GIFT, site of fertilization

is fallopian tube, not laboratory.

148. (c) Sertoli cells are found in the walls ofseminiferous tubules of the testes. They

anchor and provide nutrition to thedeveloping germ cells especially thespermatids.

150. (a) Menopause is the period when ovulationand menstrual cycle stop in human females.The period of menopause is between 45-55years.

154. (a) Fat is mainly digested by pancreatic lipasewhile protein is digested by enzymes inpancreatic juice, intestinal juice andstomach.

155. (a) Oxyntic cells or Parietal cells, are thestomach epithelium cells that secretegastric acid intrinsic factor. These cellssecrete hydrochloric acid (HCI) whichmakes the gastric juice acidic (pH = 2.0-3.0).

Alpha cells of islets of Langerhanssecretes glucagon hormone which increasethe glucose level in the blood byconverting glycogen to glucose in livercells. Kupffer's cells are specialized cellsin the liver that destroy bacteria, foreignproteins, and worn-out blood cells.Sebaceous glands and microscopic glandsin the skin that secrete an oily/waxy matter(called sebum) to lubricate the skin andhair of mammals.

156. (a) 70% to 75% C02 is transported as primarybuffer of the blood. Bicarbonate ion

(HC03) in blood plasma. When C02diffuses from tissues into blood then it is

acted upon by the enzyme carbonicanhydrase.

157. (b) ' Bundle of His' are a typical cardiac musclefibres, connecting the atria with ventricle.

159. (d) A barr body is one of the X-chromosomesin somatic cells of females. If there are more

X-chromosomes, then there will be more

barr bodies.

160. (c) Genetic drift is also known as Sewall Wrighteffect. It refers to the random changes in

gene frequencies in a population by chance,either due to intensive inbreeding or death

of a small section of population by naturalcalamity. Its effect is more marked in smallisolated population.

161. (b) Gause,s hypothesis states that two differentcompeting species cannot coexist togetherfor a long in the same niche, one has to get

eliminated by the other competing species.if they do coexist, then they do so as aresult of niche differentiation, i.e.

differentiation of then realized niches.

162. (d) Karl Von Frisch, carried out many

experiments and determined that when aforaging bee returns to the hive, it performsa waggle dance. Honey is predominantlyglucose and fructose. Dorsata is a biggerbee than Apis indica (a medium sized bee).Bees wax is secreted by special wax glandsto make compartments.

163. (c) Baldness is a sex influenced trait. The

dominance of alleles may differ inheterozygotes of the two sexes.

164. (d) Biometric genetics is the mathematical orstatistical study of genetic phenomenon.

In this branch, data of various genetic traitsare analysed by applying the principles ofstatistics. It helps in the investigation ofvarious genetic principles and checks theircorrectness and probability.

166. (d) Molecule (a) represents structure of

morphine. Morphine is the most abundantalkaloid found in opium, the dried sap (latex)derived from shallowly slicing the unripe

seedpods of the opium, or common and/oredible, poppy Papaver somniferum.

Morphine is a potent opiate analgesic drugthat is used to relieve severe pain.


SOLUTIONS s-65

167. (d) Electroencephalogram is the recording of

electric potentials originating from differentparts of the brain in the form of waves.

Fractionation is the technique of rupturing

cells and separating their components

especially cell organelles for studying theirchemistry and functions. Electrophoresis

is the technique of separation of charged ]77solutes on the basis of their differential

migration in an applied electric field.

168. (a) Actin and tropomyosin are part of thinfilaments of skeletal muscle. Tubulin is

presents in microtubules. Myosin is

muscle protein.

171. (a) Glucagon is secreted by d-cells of the is- 178.

lets of Langerhans in the pancreas. It in-

creases the concentration of glucose in theblood by stimulating the breakdown of gly-

cogen.

172. (b) Parathyroid gland secretes parathormone

which regulates Ca2+ level in blood. Ante-

rior lobe of pituitary secretes the following

hormones growth hormone, ACTH, TSH,FSH. LH. Posterior pituitary secretes vaso-

pressin and oxytocin.

The intermediate lobe (pars intermedium)

of the pitutary gland secretes MSH whichcauses dispersal of pigment granules in the ' 80-

pigment cells which give colour to the skin.

173. (b) Nicotine and acetylcholine have the same

receptors-Nicotinic cholinergic receptorsand hence have the same action.

176. (a) PCR is now a common and often

indispensable technique, developed in 1984

by Kary Mullis, used in medical and

biological research labs for a variety of

applications. These include DNA cloning

for sequencing, DNA-based phylogeny, or

functional analysis of genes; the diagnosisof hereditary diseases; the identification

of genetic fingerprints (used in forensicsciences and paternity testing); and thedetection and diagnosis of infectiousdiseases. In 1993 Mullis won the Nobel

Prize in Chemistry for his work on PCR.

(c) Whenever our body gets attacked by some

foreign invaders, our body,s immunesystem produces some chemicals to kill or

to react against the invader. Thesechemicals are actually made up of

carbohydrates & proteins i.e. glycoproteins

called antibody.

(c) Tetanus toxoid is a vaccine consisting of

growth products of Clostridium tetanitreated with formaldehyde serving as an

active immunising agent. Hence it is

weakened germs. The first tetanus toxoid

(inactivated toxin) was produced in 1924

and was used successfully to preventtetanus in the armed services during WorldWar II. In the mid-1940s, tetanus vaccine

was combined with diphtheria toxoid and

inactivated pertussis vaccine to make thecombination DTP vaccine for routine

childhood immunization.

(d) In the graph, the line A represents regula-

tor, line B represents conformer and line C

represents partial regulator. Organism that

are able to maintain homeostasis by physi-

ological means that ensures constant body

temperature are called regulators. Organ-ism that are not able to maintain a constant

internal temperature are called conformers.

Partial regulators are organisms that have

the ability to regulate, but only over a lim-

ited range of environmental conditions, be-

yond which they simply conform.


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