bdkbZ 12

U;wDyhbd vEy
bdkbZ dh :ijs[kk
12-1 çLrkouk DNA fod`rhdj.k xq.kuk'ku

mÌs'; DNA dk izfrd`fr

12-2 U;wDyhbd vEyksa dh tSfod DNA dh cgq:irk

Hkwfedk
12-6 jkbcksU;wDyhd vEy (RNA)
12-3 U;wDyhbd vEyksa ds ÄVd
jkbckslkseh RNA (rRNA)
U;wfDyvkWlkbM vkSj U;wfDyvkWVkbM
nwr RNA (mRNA)
12-4 ikWfyU;wfDyvksVkbM dk xBu
varj.k RNA (tRNA)
vkSj çfrfuf/kRo
12-5 fMvkWDlhjkbcksU;wDyhbd vEy 12-7 vkuqoaf'kd dksM
(DNA) 12-8 lkjka'k
D;k gS tks f}dqaMfyuh dks vkil esa 12-9 var eas dqN iz'u
cka/ks j[krk gS\
12-10 mÙkj

12.1 çLrkouk
geus bdkbZ 10 vkSj bdkbZ 11 esa fyfiMksa dk o.kZu fd;k Fkk ;s tSo v.kqvksa dk oxZ gS
ftuds lewg eq[; :i ls lkekU; foys;rk xq.kksa (solubility properties) ds vk/kkj ij
cuk, x, gSaA ml bdkbZ esa vkius fyfiMksa dh lajpuk (structure) ds ckjs esa lh[kkA
vkius tSo f>fYy;ksa dh lajpuk ds ckjs esa Hkh lh[kkA vkidks ;kn gksxk fd f>fYy;ka
dksf'kdk lajpuk dk ,d egRoiw.kZ fgLlk gSa] vkSj thfor thoksa ds fy, egRoiw.kZ gSaA
bl bdkbZ esa ge ,d vkSj rjg ds vko';d&tSo&v.kq dk v/;;u djsaxs ftls
U;wDyhbd vEy dgrs gSaA ikWfylSdsjkbM dh rjg ;s v.kq Hkh tSo cgqyd
(biopolymers) gSa vkSj tho/kkfj;ksa ds egRoiw.kZ ?kVd (components) gSaA bl bdkbZ
esa vkidks U;wDyhbd vEyksa ds tSfod (biological) egRo ds ckjs esa tkudkjh feysxhA
blds vykok vki U;wDyhbd vEyksa dh fdLeksa vkSj fMvkWDlhjkbcksU;wDyhbd vEy
(DNA) dh dqaMfyuh; (helical) lajpuk ds ckjs esa lh[ksaxsA izksVhuksa vkSj ikWfyisIVkbMksa
ds tSo la'ys"k.k (bisoynthesis) esa jkbcksU;wDyhbd vEy (RNA) ,d egRoiw.kZ Hkwfedk
50
fuHkkrs gSaA bdkbZ 13 esa DNA çfr—fr vkSj RNA ds vuqys[ku dk v/;;u djsaxsA
bdkà 12 U;wDyhbd vEy

mÌs';
bl bdkbZ ds v/;;u ds ckn vki%

 U;wDyhbd vEyksa ds izdk;ksZa (functions) dh O;k[;k dj ldsax;s

 U;wDyhbd vEyksa dh lajpuk dk o.kZu dj ldsax;s

 jkbcksU;wDyhd vEyksa (RNAs) vkSj fMvkWDlhjkbcksU;wDyhbd (DNAs) vEyksa

ds chp varj tku ldsaxs;

 fofHkUu izdkj ds RNAs dh Hkwfedk dk o.kZu dj ldsaxs;

 DNA dh f}dqaMfyuh (double helix) lajpuk dh O;k[;k dj ldsax;s vkSj

 vkuqoaf'kd dksM dk o.kZu dj ldsaxs A

12.2 U;wDyhbd vEyksa dh tSfod Hkwfedk

U;wDyhbd vEy o`gn.kq (macromolecule) gSa tks tho/kkfj;ksa esa ;k rks eqDr voLFkk esa
vFkok izksVhuksa ds lkFk feydj U;wfDyvksizksVhuksa ds :i esa gksrs gSaA vikdks bdkbZ 1
dh ;g ckr ;kn gksxh fd dksf'kdk ds 'kq"d Hkkj dk yxHkx 7% bu U;wDyhbd
vEyksa dk cuk gksrk gSA vki dHkh&dHkh vk'p;Z djrs gksaxs fd ekuo ls ekuo gh
D;ksa iSnk gksrk gS ;k fQj ?kksMs+ ls ?kksMk+ gh D;ksa tUe ysrk gS vkSj bZ- dksykbZ ls
dsoy bZ- dksykbZ gh D;ksa curs gSaA ;g vke iz'u gS fd vuqoaf'kdrk (heredity) ds
ihNs dkSu ls dkjd (factors) gSa\ bu lHkh iz'uksa dh dqath ,d izdkj dk U;wDyhbd
vEy gS ftls fMvkWDlhjkbhcksU;wDyhbd vEy (DNA) dgrs gSaA vkidks Lej.k gksxk fd
DNA Øksekslkse (chromosomes) esa ekStwn gksrk gS vkSj ,d ih<+h ls nwljh ih<+h esa
tkrk gSA blesa izR;sd ikS/ks ;k izk.kh ds ckjs esa fof'k"V tkudkjh gksrh gS vkSj oLrqr%
;g tkudkjh Hkh gksrh gS fd tho/kkfj;ksa esa gj dksf'kdk D;k dj ldrh gSA ;g
otg gS fd bls dHkh&dHkh ^^thou dh Mksj** dgk tkrk gSA

gesa bl ckr dk Hkh vk'p;Z gks ldrk gS fd tho (organism) esa izksVhu v.kq ifj'kq)
(precise) ,sehuksa vEy vuqØe (sequence) fdl rjg curk gS ftlls fd ;g
'kjhjfØ;kRed :i ls (physiologically) lfØ; cu ldsA izR;sd tho dks izksVhuksa dh
t:jr iM+rh gS vkSj tho/kkfj;ksa esa yxHkx izR;sd vfHkfØ;k (reaction) ,ut+kbe ls
mRizfjr (catalysed) gksrh gSa ,Ut+kbe Hkh ,d izksVhu gSA ,Ut+kbe viuh fØ;k esa
vR;f/kd fof'k"V (specific) gksrh gS] tuu (reproduction) ds nkSjku gj tho vkuh
larfr esa ,Ut+kbeksa ds fof'k"V leqPp; (sets) iSnk djus dh {kerk dk ikjxeu
(transmit) djrk gSA ;s ,Ut+kbe ml tho ds fy, vf}rh; ;kuh cstksM+ gksrh gSA ;g
tkudkjh fufeZr ,Ut+kbeksa ds :i esa ugha nh tkrh cfYd U;wDyhbd vEyksa ij
tkudkjh ds :i esa dksfMr (coded) gksrh gSA ;s viuh ckjh esa ,sehuksa vEyksa ls
fofHkUu izksVhuksa ds la'ys"k.k dks izHkkfor vkSj fu;af=r djrs gSaA

tSlk fd geus igys mYys[k fd;k gS] tho/kkfj;ksa esa ge dksf'kdk esa U;wDyhbd vEy
gksrs gSaA dksf'kdk esa ;s eq[;r% jkbckslkse vkSj dsUnzd (nucleus) esa gksrs gSaA vxys 51
[kaM 4 fyfiM v©j U;wfDyd vEy
Hkkx esa ge bu egRoiw.kZ tSo v.kqvksa dh lajpuk dk o.kZu djsaxsA vki bu v.kqvksa esa
ekStwn fofHkUu lajpukRed ;wfuVksa ds ckjs esa v/;;u djsaxsA vki ;g Hkh v/;;u
djsaxs fd fdl rjg dh ca/krk,a (linkage) bu ;wfuVksa dks vkil eas cka/k j[krh gSaA

12.3 U;wDyhbd vEyksa ds ÄVd

U;wDyhbd vEy ikWfyU;wfDyvksVkbM gksrs gSa vFkkZr~ os U;wfDyvksVkbMksa dh cgqyfdr
(polymerised) Ük`a[kyk,a gksrs gSaA ;s ,d U;wfDyvksVkbM dh 5 fLFkfr ls ysdj layXu
(adjacent) U;wfDyvksVkbM dh 3 fLFkfr rd QSys Q+kWLQksMkb,LVj ca/krkvksa }kjk tqMs+
jgrs gSaA bl rjg U;wDyhbd vEyksa eas iqujko`Ùk (repeated) 5’→3’ Q+kWLQksMkb,LVj
vkca/k (bond) gksrs gSa tks vusd ,dyd (monomer) U;wfDyvksVkbM ;wfuVksa dks tksM+rs
gSaA U;wfDyvksVkbM] Q+kWLQsV dh ,d] 'kdZjk dh ,d vkSj fo"kepØh; {kkjd
(heterocyclic base) dh ,d ,d ;wfuV ds cus gksrs gSa tSlk fd uhps fpf=r fd;k
x;k gS%
O Nitrogen conaining base
Phosphate

,d U;wfDyvksVkbM
U;wfDyvksVkbMksa ds ckjs esa vki miHkkx 12-3-1 esa v/;;u djsaxsA geus fp= 12-1 esa
,d ikWfyU;wfDyvksVkbM Ük`a[kyk n'kkZbZ gSA
NH2

O N NH2
5'
O P O CH2 N
O N N
OH 4' H H 1'
Adenine 5'
Adenosine-5'- CH2
phosphate H 3' 2' H O N N 5'
*
O R 1' A
H O
H O 3'
H
H H 2' H H3C
H H3C N
N
O O R
5' 5'
N O N O 3'
O P O CH2
O - H2O O P O CH2
Thymine O T
OH 4' H H 1'
OH 4' 1'
H
Thymidine-5'
phosphate H 3' 2' H 3'
* H 2' H O
5'
O R
R N
H O NH
H O 5'
N O P O CH2 N
O NH O N NH2
5'

3' O P O CH2 N OH 4' H 1' G

O N NH2 NH2
3'
OH 4' H H 1' Guanine H 2' H
H H N
Guanosine-5'- 3'
*
2'
O R
pphosphate 5'
O R
O N O
H P O CH2
NH2 O C
H
N
OH 4' H H 1'
O
5' H 3' 2' H
O P O CH2 N O
O
Cytosine R
OH 4' H H 1' O
Cytidine-5'-
H 3' 2' H
phosphate *
O R

fp= 12-1: ,d U;wDyhbd vEy Ük`a[kyk dk vius U;wfDyvksVkbM ,dyd ls lEcU/kA nkguh rjQ DNA
jTtqqd (DNA strand) dk ,d NksVk Hkkx gSA ckbZa vkSj blds la?kVu (constituent)
U;wfDyvksVkbM ,Dyd gSA sUVksl ;wfuVksa ij rkjd (asterisks) bu oy;ksa (rings) dh 2' fLFkfr
dks crkrs gSa tgka vxj U;wDyhbd vEy RNA gks rks nwljk OH lewg Hkh gksxk ¼;g ekurs gq,
fd ;wjsfly] Fk;ehu dks Hkh izfrLFkkfir dj nsrk gS½A funsZ'k 5’→3’ dk ;g vFkZ gS fd iw.kZ
jTtwd esa igyh isUVksl ;wfuV ds C-5 ij ,d Q+kWLQ+sV ,LVj lewg vkSj nwljs fljs ij ,d
v&,LVjhd`r (unesterified) C-3 OH gksxkA blds vykok {kkjdksa dk vuqØe 5 fljs ls 3
52 fljs dh vksj fy[kk tkrk gSA bl rjg Åij n'kkZ;k x;k vuqØe ATGC gksxk u fd CGTA
bdkà 12 U;wDyhbd vEy

,dyd ;wfuVksa ;kuh U;wfDyvksVkbMksa ds foU;kl ds v/;;u ds ckn ns[ksaxs fd

U;wDyhbd vEyksa ds jh<+ (backbone) dk iSVuZ ,d ds ckn ,d Q+kWLQsV vkSj 'kdZjk
;fuVsa gSaA ;gka ij 'kdZjk isUVksl v.kq gSA ;gh isUVksl 'kdZjk gS tks fHkUu ukbVªkstuh
(nitrogenous) {kkjd ls layXu jgrh gSA U;wDyhbd vEyksa dh fof'k"Vrk {kkjdksa ds
vuqØe vkSj jh<+ dh yEckb esa gksrh gSA jh<+ ra= (system) dks vkil esa cka/ks j[krk
gS tcfd {kkjdksa dk vuqØe vkuqoaf'kd tkudkjh ys tkrk gSA vkids fy, U;wDyhbd
vEyksa ds v/;;u dks vklku vkSj Li"V cukus ds fy, geus uhps U;wDyhbd vEy ds
,d [kaM dks ljy <ax ls fu:fir (represent) fd;k gSA

O A P
O A
O P O Pentose
OH O T P
O T
O P O Pentose
G P
OH O O G
O P O Pentose
CH 3
P
CH 3 OH O C O
Pentose = C
O P O Pentose
Base = A, T, G, C
P
hosphate = P O

U;wDyhbd vEyksa dh lagr (compact) lajpuk,a

vc rd vki ;g le> gh x, gksaxs fd ,d cM+s vkSj tfVy yxys okys U;wDyhbd

v.kq dks ikWfyU;wfDyvksVkbM ekuk tk ldrk gS tgka ,d U;wfDyvksVkbM dh 5
fLFkfr vkSj layXu U;wfDyvksVkbM dh 3fLFkfr ds chp ,d Q+kWLQksMkb,LVj vkca/k
cu tkrk gSA ijEijkxe <ax ls U;wDyhbd vEy ds vuqØe dks fy[kus dh fn'kk
5→3gS ftlesa 5VfeZul ges'kk gh ckbZa vksj gksrk gSA bl rjg
isUVkjkbcksU;wfDyvksVkbM AUGCG dk vFkZ ;g gS fd ,sMsukslhu (A) 5VfeZuy gS vkSj
Xokukslhu (G) 3VfeZuy gSA ;g Li"V :i ls GCGUA ls fHkUu gS tSlk fd uhps
fn[kk;k x;k gS%

G A
O O
O P O Pentose O P O Pentose
OH O C OH O U
O P O Pentose O P O Pentose
OH G OH G
O O
O P O Pentose O P O Pentose
5' 5'
G
CG
OH O U AU OH O C
UA G
O P O Pentose CG
O P O Pentose
3' 3'
OH OH
O A O G
O P O Pentose O P O Pentose

O O

U;wDyhbd vEy jaxghu Bksl inkFkZ gSA ;s nks izdkj ds gksrs gSa% jkbcksU;wDyhbd vEy
(RNA) vkSj fMvkWDlhjkbcksU;wDyhbd vEy (DNA)A nksuksa tSo cgqydksa
(biopolymers) esa iqujkorhZ ,dyd U;wfDyvksVkbM ;wfuVsa gksrh gSa] RNA vkSj DNA esa 53
[kaM 4 fyfiM v©j U;wfDyd vEy
nksuksa esa gh ,dyd ;wfuVsa isUVksl 'kdZjk] ukbVªkstuh {kkjd ;kuh ifjfeMhu ;k I;wjhu
vkSj ,d Q+kWLQ+sV lewg dh cuh gksrh gS%
Nucleic acid (polymers of nucleotides)
4
5 H2O, catalyst
1 N
Nucleotidees (monomeric units of nucleic acid)
2 6
N H2O, catalyst
1
fifjfeMhu
Pyrimidine
6 7
5 N O HO HO
1 N O OH O OH
8
HO P OH + H H H H
2 +
N 4 N7 H H H H
3 H OH OH H
OH OH
I;wjPurine
hu Ribose Deoxyribose
(from DNA)
(from RNA)
Nitogen bas(heterocyclic ammine
NH2 O O O NH2
N H N H CH3 H
N N N N N
+
N N H2N N N O N O N O N
H
H H H
H
Adenine Guanine Thymine Uracil Cytosine
A G T U C
(from DNA) (from RNA)
U;wDyhbd vEyksa ds la?kVu

vki ns[ksaxs fd RNA vkSj DNA esa dqN lk>k la?kVu gSA ;s Q+kWLQ+sV lewg] I;wjhu
{kkjd] tSls fd ,sMsuhu (A) vkSj Xokuhu (G), vkSj fifjfeMhu {kkjd lkbVkslhu (C)A
fQj Hkh] RNA vkSj DNA ds chp izeq[k varj ;g gS fd RNA esa isUVksl 'kdZjk]
jkbcksl gksrh gS tcfd DNA esa isUVksl 'kdZjk ds :i esa 2-fMvkWDlhjkbcksl gksrk gSA
blds vfrfjDr {kkjd ;wjsfly (U) dsoy RNA esa ik;k tkrk gS vkSj {kkjd Fkk;ehu
(T) dsoy DNA esa ekStwn gksrk gSA DNA vkSj RNA dk o.kZu ge miHkkx 12-5 vkSj
15-6 esa foLrkjiwoZd djsaxsA vkb, igys ge U;wfDyvksVkbMksa ds ckjs esa vkSj v/;;u
djrs gSaA

cks/k iz'u 1
mi;qDr dFku ij lgh ¼ ½ dk fu'kku yxkb,% U;wDyhbd vEy blfy, egRoiw.kZ
gksrs gSa D;ksafd os
d½ tfVy vkSj cM+s v.kq gSa ( )

[k½ vk;u fofue; (ion exchange) esa fgLlk ysrs gSa ( )

x½ dksf'kdk dks LFkkf;Ro nsrs gSa ( )

?k½ vkuqoaf'kd inkFkZ gksrs gSa ( )

54
bdkà 12 U;wDyhbd vEy

12-3-1 U;wfDyvkslkbM vkSj U;wfDyvksVkbM

tc fdlh ukbVªkstuh {kkjd dks] Hkys gh og I;wjhu gks ;k fifjfeMhu gks] fdlh
isUVksl 'kdZjk ¼jkbcksl ;k fMvkWDlhjkbcksl½] ls lgla;kstdrk (covalent) can dj
fn;k tkrk gS rks cuus okyk v.kq U;wfDyvkslkbM dgykrk gSA U;wfDyvkslkbM esa cuus
okyk vkca/k C-1 ;kuh isUVksl 'kdZjk ds 1 vkSj ;k rks fifjfeMhu {kkjd ds N-1 vFkok
I;wjhu {kkjd ds N-9 ds chp gksrk gSA tks U;wfDyvkslkbM curk gS mldk uke
izfØ;k esa 'kkfey gksus okys isUVksl ij fuHkZj djrk gSA ;fn isUVksl jkbcksl gS rks
cuus okyk U;wfDyvkslkbM jkbcksU;wfDyvkslkbM dgykrk gS vkSj vxj
fMvkWDlhjkbcksl gS fMvkWDlhjkbcksU;wfDyvkslkbM dgykrk gSA ,sMsukslhu] Xokukslhu]
lkbfVMhu vkSj ;wfjMhu lkekU; jkbcksU;wfDyvkslkbM gSA blh rjg
fMvkWDlhjkbcksU;wfDyvkslkbMksa ds uke gSa fMvkWDlh,sMsukslhu (dA) fMvkWDlhFk;feMhu
(dT) vkfnA lkj.kh 12-1 esa geus vk/kkj uke vkSj muds laxr U;wfDy;kslkbM vkSj
U;wfDy;ksVkbM uke fn, gSaA
NH2 O NH2 O
H N
N N N HN
N

H2N N N O
N N O N HO N
HO
HO HO O O
O O
H H H H
H H H H
H H H H
H H H H
OH OH OH OH OH OH
OH OH
Cytidine Uridine
Adenosine Guanosine

NH2 O NH2 O
H N
N N N HN
N

H2N N N O N
N N O N HO
HO
HO HO O O
O O
H H H H
H H H H
H H H H
H H H H
OH H OH H OH H
OH H

2'-Deoxyadenosine 2'-Deoxyguanosine 2'Deoxycytidine Thymidine

U;wfDyvkslkbM

lkj.kh 12-1 {kkjdksa ds uke] U;wfDyvkslkbM vkSj U;fDyvksVkbM

{kkjdksa ds U;wfDyvkslkbM jkbcksU;fDyvksVkbM fMvkWDlhjkbcksU;fDyvksVkbM

uke
,sMsuhu ,sMsukslhu 2’-fMvkWDlh ,sMsukslhu-5-Q+kWLQsV 2’-fMvkWDlh,sMsukslhu-5-
,sMsukslhu Q+kWLQsV
Xokuhu Xokukslhu 2’-fMvkWDlh Xokukslhu-5-Q+kWLQsV 2’-fMvkWDlhXokukslhu-5-
Xokukslhu Q+kWLQsV
lkbVkslhu lkbfVMhu 2’-fMvkWDlh lkbfVMhu-5-Q+kWLQsV 2’-fMvkWDlhlkbfVMhu-5-
lkbfVMhu Q+kWLQsV
Fkk;ehu ----- Fk;feMhu ---------- Fk;feMhu-5-Q+kWLQsV
;wjsfly ;wfjMhu ------- ;wfjMhu-5-Q+kWLQsV -----
55
[kaM 4 fyfiM v©j U;wfDyd vEy
tc Q+kWLQsV lewg U;wfDyvkslkbM ls layXu gks tkrk gS rks cuus okys v.kq dks
U;fDyvksVkbM dgrs gSaA Q+kWLQ+ks,LVj ca/krk cuus ds fy, lcls lkekU; LFky (site)
jkbcksl ;k fMvkWDlhjkbcksl v.kq dh 5 fLFkfr (position) gSA
NH2
NH2
N
N
N
HO O N
O O
N N H H
HO P O 5' H H
O
OH H H O H
H H O P OH
OH OH
OH
Adenosine-5'-monophosphate 2'-Deoxycytidine-3'-monophosphate
(a ribonucleotide) (a deoxyribonucleotide)

tc Q+kWLQ+ksfjd vEy dks P2O5 ds lkFk xeZ fd;k tkrk gS rks ;g ty d¨ [kks nsrk
gS] ftlls ikbjksQk+ WLQ+sV vEy uked Q+kWLQ+ks,sugkbMªkbM curk gSA VªkbQ+‚LQ+ksfjd
vEy vkSj mPp i‚yhQ+‚LQ+ksfjd vEy Hkh curs gSaA
O O O O O O

5 HO P OH HO P O P OH + HO P O P O P OH
P2O5
OH OH OH OH OH
OH
Phosphoric acid Pyrophosphpric acid Triphosphoric acid

isUVksl dh C-5fLFkfr ls ,d ;k vf/kdred rhu Q+kLQ+sV lewg layXu fd, tk

ldrs gSa ftlds QyLo:i eksuks&] Mkb vkSj VªkbQ+kWLQ+ksU;wfDyvksVkbM cu tkrs gSaA
igyk Q+kWLQsV lewg ,d ,LVj ca/krk ls layXu gksrk gS ysfdu vxys nks Q+kWLQ+sV
lewg Q+kWLQ+ks,sugkbMªkbM ¼;kuh ikbjksQk+ WLQ+sV½ ca/krkvksa }kjk layXu jgrs gSaA
NH2 NH2 NH2
N N N
N N N
O O O O O O
N N N N N N
HO P O 5' HO P O P O 5' HO P O P O P O 5'
O O O
OH H H OH OH H H OH OH OH H H
H H H H H H
OH OH OH OH OH OH

Adenosine-5'-monophosphate Adenosine-5'-diphosphate Adenosine-5'-triphosphate

(AMP) (ADP) (ATP)

NH2 NH2 NH2

N N N
N N N
O O O O O O
N N N N N N
HO P O 5' HO P O P O 5' HO P O P O P O
O O 5' O
OH H H OH OH H H OH OH OH H H
H H H H H H
OH H OH H OH OH

2'-Deoxyadenosine-5'-monophosphate 2'-Deoxyadenosine-5'-diphosphate 2'-Deoxyadenosine-5'-triphosphate

(dAMP) (dADP) (dATP)
56
bdkà 12 U;wDyhbd vEy

ifjHkk"kk ds vuqlkj gkykafd U;wfDyvksVkbM] U;wfDyvkslkbM Q+kWLQ+sV gS ysfdu

lkekU;r;k dqN nwljs Q+kWLQsV tSl fd ikbjksQk+ WLQ+sV] ikWfyQ+klQ+sV vkSj fo"kepØh;
{kkjdksa ds N-XykbdkslkbMksa ds Q+kLQ+sV Hkh U;wfDyvkslkbMksa dh ifjHkk"kk esa 'kkfey
fd, tkrs gSaA U;wfDyvkslkbM ds isUVksl ls Q+kWLQksfjd vEy dh lyaXurk jkbcksl
v.kq esa 23;k 5ij vkSj fMvkWDlhjkbcksl v.kq esa 3;k 5ij gks ldrh gSA
U;wDyhbd vEyksa ds ,Ut+kbeh ty&vi?kVu (enzymatic hydrolysis) ls 3 ;k
5Q+kLQ+sV curs gSa tks ;g ladsr djrk gS fd bu ;kSfxdksa (compounds) esa Q+kLQ+sV
ca/k (link) fu'p; gh 3;k 5 fLFkfr;ksa ij gksuk pkfg,A

dksf'kdk esa vusd U;wfDyvksVkbM eqDr :i esa ik, tkrs gSaA os fofo/k izdk;Z djrs gSaA
U;wDyhbd vEyksa dh vk/kkjHkwr ;wfuVksa dh Hkwfedk ds vykok os lg&,Ut+kbe
(coenzymes) ds :i esa Hkh dk;Z djrs gSaA os tSola'uys"k.k vfHkfØ;kvkas
(biosynthetic reactions) esa Hkkx ysrs gSa vkSj ÅtkZ mueksph (energy releasing)
vfHkfØ;kvksa ls ÅtkZ pkgus okyh vfHkfØ;kvksa dks ÅtkZ ys tkus esa egRoiw.kZ Hkwfedk
fuHkkrs gSaA ,sMsukslhu VªkbQ+kWLQsV (ATP), Xokukslhu VªkbQ+kWLQ+sV (GTP) vkSj ;wfjMhu
VªkbQ+kWLQ+sV (UTP) dqN ,sls U;wfDyvksVkbM gS tks ÅtkZ dk ogu djrs gSaA

cks/k iz'u 2
tks ;kSfxd U;wDyhbd vEy dk la?kVu ugha gS ml ij lgh ¼ ½ dk fu'kku yxkb,%

d½ jkbcksl ( )

[k½ ukbVªkstuh {kkjd ( )

x½ Q+kWLQ+sV vof'k"V (residual) ( )

?k½ ,sehuksa vEy ( )

cks/k iz'u 3
fuEufyf[kr esa ls çR;sd ds fy, lajpuk cuk,a:
d½ ;wMhih [k½ th,eih x½ VhVhih ?k½ lkbfVMhu&5'&i‚LQsV

12-4 ikWfyU;wfDyvksVkbM dk xBu vkSj çfrfuf/kRo

i‚yhU;wfDyvksVkbM ¼U;wfDyd vEy½ Q+‚LQ+ksMkb,LVj ca/krk ls tqMs+ U;wfDyvksVkbM
mi&bdkb;¨a ds yacs jTtqd ls cus gksrs gSaA ;s laca/k ,d U;wfDyvksVkbM ds lewg dks
vxys U;wfDyvksVkbM ds lewg ls tksMr+ s gSaA bl rjg ds laca/k fp= 12-1 esa fn[kk,
x, gSaA U;wfDyd vEy ds fuekZ.k esa U;wfDyvksVkbM VªkbQ‚LQsV çkjafHkd lkexzh gksrs
gSA DNA dks DNA iksyhejst uked ,atkbe }kjk la'ysf"kr fd;k tkrk gS] vkSj
RNA dks RNA iksyhejst uked ,atkbe }kjk la'ysf"kr fd;k tkrk gSA
U;wfDyvksVkbM jTtqd ,d U;wfDyvksVkbM VªkbQ‚LQsV ds 3' OH lewg }kjk nwljs
U;wfDyvksVkbM VªkbQ‚LQsV ds Q‚LQksjl lewg ij ukfHkdLusgh (nucleophilic) 57
[kaM 4 fyfiM v©j U;wfDyd vEy
vfHkfØ;k ds ifj.kkeLo:i curk gS] ,d Q+kWLQ+ks,sugkbMªkbM ca/ku dks rksMr+ k gS vkSj
ikbjksQ+kWLQ+sV dks vyx dj nsrk gSA bl pj.k esa cuus okyk mRikn U;wfDyvksVkbM
VªkbQ‚LQsV ds nwljs v.kq ds lkFk ,d vkSj ukfHkdLusgh çfrLFkkiu vfHkfØ;k djrk
gS vkSj var esa dbZ pj.kksa ds ckn ,d iksyhU;wfDyvksVkbM curk gSA
iksyhU;wfDyvksVkbM ds cuus dks fp= 12-2 esa n'kkZ;k x;k gSA

O O O

HO P O P O P O Base
5'
O O O O
OH OH OH H
H HO P O P O P O Base
5'
O
OH OH OH OH H
O O O H
HO P O P O P O 5'
Base O
O
OH OH OH -
H O P O
H
O Base
O O O OH 5'
O
H
HO P O P O P O Base
5'
O H
OH OH OH H OH
H O O O
3'
O HO P O P O P O 5'
Base
5' - O
O P O OH OH OH H
O Base H
5'
O OH
H
H
3'
O
-
O P O
3'
O Base
5'
O
H
H
3'

OH
......Polynucleotide

fp= 12-2: iksyhU;wfDyvksVkbM dk cuuk

tSlk fd igys fp= 12-1 esa fn[kk;k x;k gS vkSj fp= 12-2 esa Hkh] c<+rs cgqyd
5'→3' fn'kk esa la'ysf"kr gksrs gSaA Mhv‚DlhjkbcksU;wfDyvksVkbM ds ctk;
jkbcksU;wfDyvksVkbM dk mi;ksx djds RNA jTtqd Hkh mlh rjg curs gSaA U;wfDyd
vEy dh çkFkfed lajpuk jTtqd esa vk/kkjksa dk Øe gSA bl Hkkx esa U;wfDyvksVkbM
vkSj iksyhU;wfDyvksVkbM ds xBu dk o.kZu djus ds ckn] vkb, vc ge U;wfDyd
vEy ds çdkjksa ds ckjs esa foLrkj ls crkrs gSa] tSls Mh,u, vkSj vkj,u,A

12.5 fMvkWDlhjkbcksU;wDyhbd vEy (DNA)

DNA D;k gS\ tSlk fd igys ckrk;k gS] ;g fMvkWDlhjkbcksU;wfDyvksVkbM dk cgqyd
gSA bldh lajpuk RNA ls feyrh tqyrh gSA varj ;g gS fd RNAs esa
Q~;jw suksjkbcksl dh rqyuk esa isUVksl ;wwfuV 2&fMvksDlhQ~;jsuksjkbcksl gS vkSj pkj
ukbVªkstuh {kkjd gS ,sMsuhu (A), Fkk;ehu (T), Xokuhu (G) vkSj lkbVkslhu (C)A
58 DNA esa ;wjsfly dh txg Fkk;ehu ys ysrk gSA DNA vuqoaf'kdrk dh ewy ;wfuV gSA
bdkà 12 U;wDyhbd vEy

DNA dh lqLi"V f}rh;d lajpuk gksrh gS ftlesa nks Lora=

ikWfy&fMvkWDlhjkbck&U;wfDyvksVkbM jTtqd gksrs gSaA ;s nksuksa ,d lk>k v{k (axis)
ds pkjksa vksj dqaMfyr jgrs gSa vkSj gkbMªkstu vkca/kksa ls vkil esa lEc) jgrs gSaA
DNA dh ;g lajpuk 1953 esa ÝkafUll fØd vkSj tkUlu okVlu us izLRkfor dh Fkh
¼fØd vkSj okVlu ekWMy (Watson & Crick Model) ds uke ls tkuh tkrh gS½
bleas nf{k.korhZ dqaMfyuh (right handed helix) esa O;kofrZr (twisted) nks iwjd tRNA
jTtqd gksrs gSaA I;wjhu vkSj fifjfeMhu {kkjd rks dqaMfyuh dh Hkhrjh vkSj tcfd
Q+kWLQ+sV vkSj fMvkWDlhjkbcksl v/kkZa'k (moieties) ckgjh vksj gksrs gSa ¼fp= 12-3½A

OH
C O
T A
O P

P
T
5' P C
3' A
O G A
G C T c
G G
O P
C
P
O
T A
O A
P G
T CT
P G
3' 5' T CA
O
G C A
O P

P
O
C G
O C
HO

fp= 12-3% ¼d½ DNA f} dqaMfyuh esa iwjd {kkjd ;qXe% ,sMsuhu ges'kk Fkk;ehu ds lkFk ;qXe cukrs
gS;a Xokuhu ges'kk lkbVkslhu ds lkFk ;qXe cukrs gS;a ¼[k½ DNA f} dqaMfyuh dk
O;oLFkkRed fu:i.k] lk>k v{k ds pkjksa vksj dqaMfyr nks lfiZy jTtqd foijhr ;k
dfg, lEeq[k jTtqdksa ij {kkjdksa ds chp gkbMªkstu vkca/kksa }kjk vkil esa ca/kss jgrs gSa

bl vksj /;ku nhft, fd lHkh {kkjd fo"kepØh; oy; gS vkSj mudh ryh;
(planer) lajpuk gSA muds ry (planes) dqaMfyuh ds v{k ls yac (perpendicular)
gksrs gSa vkSj fMvkWDlhjkbcksl v.kqvksa ds ry {kkjdksa ds ryksa ls yxHkx ledks.k
(right angle) gksrs gSaA ;g ra= ,d lihZy lh<+h (spiral staircase) dh rjg gS ftlesa
lfiZy ds yEcs v{k ls yac LVsi (steps) eas gkbMªkstu vkcaf/kr (bonded) {kkjd ;qDr
gksrs gSaA ;qXeksa ds chp gkbMªkstu vkca/k yEcs v{k ds vkl&ikl dsfUnzr jgrs gSaA
iwjd jTtqd dk fopkj bl [kkst ls tUek fd {kkjdksa ds ;qXe tSls fd A vkSj T rFkk
G vkSj C ges'kk gh 1 % 1 eksyh; vuqikr esa gksrs gSaA blls ;g lq>ko feyk dh
jTtqdksa ds chp A, T ls ;qfXer gksrk gS vkSj G, C ls ;qfXer gksrk gS tSlk fd uhps
fn[kk;k x;k gS ¼fp= 12-3¼d½ v©j 12-4½%
59
[kaM 4 fyfiM v©j U;wfDyd vEy
H Hydrogen
CH3 Cytosine bonding
O H H N H
N
Adenine O
N N N N Guanine
N
H N H N
Site of Site of N
attachement to O attachement to O
nucleic acid Thymine N N H
nucleic acid N
back bone back bone
N N

Hydrogen Site of attachement to H

Site of attachement to
bonding nucleic acis back bone
nucleic acis back bone

fp= 12-4% {kkjd ;qXeksa ds chp gkbMªkstu vkca/ku ¼d½ Fk;ehu (T) vkSj ,sMsuhu (A) nks gkbMªkstu
vkca/k ls ,d {kkjd ;qXe cukrs gSa] ¼[k½ lkbVkslhu (C) vkSj Xokuhu gkbMªkstu vkca/kksa
ls nwljk {kkjd ;qXe cukrs gSa] ,sMsuhu fdl rjg Fkeehu ls {kkjd ;qXe cukrh gS mlh
rjg ls ;wjsfly (U) ls Hkh cu ldrh gS

daqMfyuh dk O;kl 1.8 nm ¼;k 18Ž gksrk gSA layXu {kkjd dqaMfyuh ds lkFk&lkFk
0.34nm (3.4Å) }kjk vyx dj fn, tkrs gSa vkSj 36 ?kwf.kZr (rotatex) gks tkrs gSaA
bl rjg dqaMfyuh lajpuk izR;sd Üka`[kyk ;k gj 3.4 nm (34 Å) ij nl
U;wfDyvksVkbM ds ckn iqujko`Ùk gksrh gS ;k dfg, nksgjkbZ tkrh gSA DNA ds
,Dl&fdj.k foorZu (diffraction) vkadM+s nwwljs ekWMy ls le>k, tk ldrs gSa ftlesa
layXu {kkjd ;qXeksa ds chp ?kw.kZu&dks.k (angle of rotation) esa FkksM+s ls lek;kstu
(adjustment) dh t:jr gksrh gSA ;g fl) fd;k tk pqdk gS fd {kkjd ;qXeksa dh
la[;k izfr orZu (turn) 10.4 gksrh gS u fd 10 tSlk fd fpjlEer (classical)
B-ekWMy ¼okVlu vkSj fØd ekWMy½ }kjk crk;k x;k FkkA bl izs{k.k (observation)
ds dkj.k DNA f}&dqaMfyuh ds fy, ,dy lajpuk dk LFkku lajpukvksa ds ,sls dqyksa
(families) }kjk ys fy;k x;k gS tks izfr orZu U;wfDyvkslkbMksa dh la[;k eas vkSj
layXu iqujkorhZ ;wfuVksa ds chp nwjh esa dqN fofHkUurk,a n'kkZrs gSaA

lkj.kh 12-2 % f}daqMfyuh ds fofHkUu :iksa ds vfHky{k.k

daqMfyuh dh izfr orZu {kkj izfr {kkjd ;qXe izfr {kkjd ;qXe daqMfyuh O;kl
fdLe ;qXe ?kw.kZu ¼va'k½ m/okZ/kj (diameter)
(vertical) yEckbZ
(nm)
(nm)

A 11 +32.7 0.256 2.3

B 10 +36.0 0.338 1.9

C 9.33 +38.6 0.332 1.9

*
Z 12 -30.0 0.371 1.8

* okekorZ (left handed) dqaMfyuh ds fy, _.kkRed (negative) ?kw.kZu

A-:i esa vkSlr ls vf/kd ;kuh 11 {kkjd ;qXe gksrs gSaA {kkjd dqaMfyuh; v{kksa ds
yac ugha gksrs cfYd ur ;kuh >qds gq, gksrs gSaA A-:i la:i.k (conformation) esa
DNA-RNA ladj (hybrid) ls feyrk tqyrk gSA ;g :i 75% vkisf{kd vknzZrk
(relative humidity) ij fn[kkbZ nsrk gS vkSj blds fy, lksfM;e] iksVSf'k;e ;k

60
lhft+;e (cesium) vk;usa mifLFkr gksuh pkfg,A
bdkà 12 U;wDyhbd vEy

B-:i izfl) okVlu vkSj fØd ekWMy gSaA ,slk le>kk tkrk gS fd ;gh :i thfor
dksf'kdkvksa esa O;kIr jgrk gSA bls mPp vkisf{kr vknzZrk (92%) vkSj fuEu vk;uh
lkanz.k (strength) okys foy;uksa dh t:jr gksrh gSA

C-:i esa B-DNA dh vis{kk {kkjd ;qXeksa dh la[;k de gksrh gSA ;g 66% vkisf{kr
vknzZrk vkSj yhfFk;e vk;uksa dh mifLFkfr esa ik;k tkrk gSA

vU; :i Hkh ik, tkrs gSa tSls fd D-:i vkSj E-:i ftuesa izfr orZu Øe'k% 8 vkSj
7-5 {kkjd ;qXe gksrs gSa vkSj Xokuhu dk vHkko gksrk gSA Z-:i lcls T;knk fnypLi
gS D;ksafd dsoy ;gh ,slk :i gS tks fd nwljksa dh rqyuk esa okeorZ daqMfyuh gSA
blesa {kkjd ;qXeksa dh la[;k izfr orZu lcls vf/kd gSA bldh lajpuk lcls de
O;kofrZr ;k dfg, dqaMfyr gksrh gSA ;g :i cgqr iryk gS vkSj 'kdZjkQ+kWLQ+sV jh<+
dqaMfyuh ds lkFk&lkFk Vs<+s&es<s+ jkLrs ls pyrk gS ¼blfy, bldk uke Z-:i iM+k
gS½ tcfd nwljs DNA f}&dqaMfyuh :iksa esa fu"dks.k pØ (smooth curve) gksrk gS
¼fp= 12-5½A
Thymine

Hydrogen Site of attachement to

bonding nucleic acis back bone

Major Grove

Grove

Minor Grove

3'
5'

Minor Grove
3'

fp= 12-5% B-DNA vkSj Z-DNA, DNA fHkUu&fHkUu f}daMfyuh lajpuk,a izLrqr djrk gSA

f}dqaMfyuh esa nks [kakps (groves) gksrs gSa&,d izeq[k vkSj ,d xks.k ¼fp= 12-3 vkSj
12-5½A ;s izksVhukas ds fy, ca/kuh LFky (binding sites) gSa] ;s [kkaps dqN vkS"k/kksa
(drugs), izfrtSfodkas (antibiotics), dSUljtuksa (carcinogens) vkSj fo"kksa ds izkjafHkd
vkf.od ikjLifjd fØ;kvksa (interactions) ds LFky Hkh gSaA

f}dqaMfyuh ds egRoiw.kZ y{k.k fuEufyf[kr gSa%

 nksuksa Ük`a[kyk,a foijhr fn'kkvksa esa pyrh gSa ;kuh os izfrlekarj (antiparallel)
gksrh gSaA 61
[kaM 4 fyfiM v©j U;wfDyd vEy
 {kkjd ;qXeu dh vko';drkvksa ds vuqlkj daqMfyuh ds nksuksa jTtqd iwjd gksrs
gSaA bl rjg] nksuksa jTtqdksa ds fHkUu&fHkUu {kkjd vuqØe gks ldrs gSa ysfdu
{kkjd ;qXeu dh fof'k"Vrk (specificity) ds dkj.k vuqØe nwljs jTtqd ds
vuqØe dks lgh&lgh fu/kkZfjr djrk gSA

 ,sMsuhu ges'kk Xokuhu ls vkSj Xokuhu lkbVkslhu ls ;qXeu djrh gSaA

cks/k iz'u 4
fuEufyf[kr dFku esa nh xbZ [kkyh txgksa dks mi;qDr 'kCnksa ls Hkfj,%

U;wDyhbd vEy ftu {kkjdksa ls curk gS mudh la[;k &&&&&& gS vkSj RNA dk
{kkjd vfHky{k.k tks DNA esa ugha ik;k tkrk og gS &&&&&&A

cks/k iz'u 5
iwjd jTtqd esa {kkjdksa dk Øe D;k g¨xk ;fn DNA jTtqd esa {kkjdksa dk
fuEufyf[kr Øe 5'→3' fn'kk esa py jgk gS\
5' G G A C A T G C 3'

4-5-1 D;k gS tks f}daqMfyuh dk vkil esa cka/ks j[krk gS\

f}daqMfyuh ds nks jTtqdksa ds {kkjd vuqØeksa ds chp vf}rh; lEcU/k ds fy, {kkjd
;qXe A : T vkSj G : C ds chp fof'k"V gkbMªkstu vkca/ku mÙkjnk;h gSA ysfdu
f}dqaMfyuh; lajpuk ds LFkkf;Ro (stability) esa bldk ;ksxnku ekewyh gksrk gSA
bldk izeq[k dkj.k dqaMfyuh ds vH;arj (interior) esa {kkjdksa dks ,d ds Åij ,d
djds j[ksa tkus ij mudh ikjLifjd fØ;k gSA /;ku nhft, fd ;s lHkh {kkjd
,sjkseSfVd fo"kepØh; ;kSfxd gksrs gSaA ty esa budh lhfer foys;rk (solubility)
;kuh ?kqyu'khyrk gksrh gS vkSj budh ,d nwljs ls ikjLifjd fØ;k djus dh izcy
izo`fÙk gksrh gSA DNA f}daqMfyuh; lajpuk esa ;s {kkjd ,d nwljs dh pksVh ij
jkf'kd`r (stacked) gksrs gSaA budks vkil esa cka/ks j[kus okys cyksa dks dHkh&dHkh
tyfojkxh (hydrophobic) ikjLifjd fØ;k,a (interactions) dgk tkrk gSA ;s
vfHkfØ;k,a tSodyk (biomembrane) fyfiM f}ijrksa (bilayers) ds Lor% fuekZ.k
¼bdkbZ 11½ vkSj izksVhuksa dks vf}rh; lajpuk,a iznku djus ds fy, ¼bdkbZ 6½
mÙkjnk;h tyfojkxh ikjLifjdfØ;kvksa ds leku rks gks ldrh gS ysfdu iwjh rjg ls
le:i (identical) ugha gksrsA blfy, bUgsa ^^fpfrdj.k ikjLifjdfØ;kvksa** ("stacking
interactions") ds uke ls iqdkjuk vf/kd lkekU; gSA

izksVhuksa dh rjg DNA dh f}rh;d lajpuk ¼f}daqMfyuh½ xje fd, tkus ij fo?kfVr
gks tkrh gSA vkb, vc bl lajpuk ij rki ds izHkko dk v/;;u djrs gSaA

4-5-2 DNA fod`frdj.k xq.kuk'ku

,d fof'k"V rki (temperature) ls T;knk xje djus ij DNA dh f}daqMfyuh;
lajpuk lekIr gks tkrh gS nksuksa jTtqd vyx gks tkrs gSa ¼fod`frdj.k&
62
bdkà 12 U;wDyhbd vEy

denaturaition½A blds ckn vusd HkkSfrd xq.kksa (physical properties) esa ifjorZu
gksrs gSa tSls fd ';kurk (viscosity) esa rsth ls deh vkSj ijkcSaxuh {ks= (ultraviolet
region) esa izdk'k vo'kks"k.kkad (light absorbance) esa c<ksÙkjh gksrh gSaA fod`rhdj.k
dh izxfr dks bu xq.kksa eas ls fdlh dh lgk;rk ls ekWfuVj fd;k tk ldrk gSA bl
dke ds fy, UV vo'kks"k.kkad esa of) ¼gkbijØksfeflVh½ lcls T;knk iz;ksx esa ykbZ
tkrh gSA DNA fufeZr (preparation) ds vo'kks"k.kkad ij rki dk izHkko fp= 12-6 esa
fn[kk;k x;k gSA rki ifjlj (range) ds e/;&fcUnq (mid-point) ftl ij ifjorZu
gksrk gS xyu rki (melting temperature) dgykrh gS vkSj Tm }kjk n'kkZ;k tkrk gSA

1.5
Absorbance

1.4
Tm
1.3

1.1
1.0
243 K 353 K 363 K 373K
Temperature

fp= 12-6% DNA dk fod`frdj.k] ftlds ckn izdkf'kr ?kuRo (optical density) esa o`f) gksrh gS]
Tm }kjk of.kZr tkrk gS

vxj foy;u dks cgqr 'kh?kzrk ls BaMk fd;k tk, rks nksuksa jTtqd vyx gh jgrs gSaA
ysfdu vxj /khjs&/khjs BaMk fd;k tkrk gS rks nks jTtqd izk;% la;qDr gksdj ewy
f}dqaMfyuh lajpuk cukrs gSaA ;g izØe iqu% izd`frdj.k (renaturation) dgykrk gSA
¼fp= 4-7½A dHkh&dHkh cgqr T;knk pH ls Hkh fod`frdj.k gks tkrk gSA

denaturation cooling renaturation

Double strands od DNS Single strands of DNA Initiating base pairing Renatured DNA
(Denaturation og DNA)

fp= 12-7% DNA ds fod`frd`r ,dy jTtqd] f}jTtqd :i esa iqu%izd`frd`r gks ldrs gSa

vxys miHkkx esa ge DNA v.kqvksa ds izfrd`frdj.k (replication) dk la{ksi esa v/;;u
djsaxsA

4-5-3 DNA dh cgq:irk

vf/kdka'k le;] DNA ,d gh tkudkjh dks ,d ih<+h ls nwljh ih<+h rd lVhd :i
ls Hkstrk gSA gkykafd] DNA esa U;wfDyvksVkbM ds vuqØe Hkh cny ldrs gSaA DNA
esa U;wfDyvksVkbM ds vuqØe esa ifjorZu dks DNA ifjorZ (DNA variants) dgk
tkrk gSA mRifjorZu (mutation) vkSj cgq:irk (polymorphism) nks 'kCn gSa ftudk
mi;ksx DNA ifjorZ dk o.kZu djus ds fy, fd;k tkrk gSA DNA çfr—fr ;k
iSjkcSaxuh (UV) fofdj.kksa vkSj jlk;uksa tSls ckgjh dkjdksa esa ds dkj.k DNA fHkUurk,a
gks ldrh gSaA ,d mRifjorZu ,d fo'ks"k O;fä esa DNA laLdj.k dks lanfHkZr djrk 63
[kaM 4 fyfiM v©j U;wfDyd vEy
gS tcfd cgq:irk ,d tula[;k ds Hkhrj DNA ifjorZ dks lanfHkZr djrk gSA eq[;
varj mRifjorZu vkSj cgq:irk ds chp gS mRifjorZu ,d fo'ks"k tho ds DNA
jTtqd ds U;wfDyvksVkbM vuqØe dk ifjorZu gS tcfd cgq:irk ,d mRifjorZu gS
tks vkcknh esa 1% ;k mlls vf/kd dh vko`fÙk ds lkFk gksrk gSA mRifjorZu ;k rks
oa'kkuqxr ;k vf/kxzfgr gks ldrs gSaA vkb, bu nksuksa 'kCnksa ij dqN vkSj foLrkj ls
ppkZ djsaA
mRifjorZu
mRifjorZu vkerkSj ij fcuk ejEer ds DNA {kfr] çfr—fr =qfV;ksa ;k eksckby
vkuqoaf'kd rRoksa ls gksrs gSaA DNA mRifjorZu ds dbZ çeq[k oxZ gSaA ,d fcanq
mRifjorZu rc gksrk gS tc ,d ,dy U;wfDyvksVkbM tksM+k tkrk gS] gVk;k tkrk gS
;k çfrLFkkfir fd;k tkrk gS ¼,sMsfuu ,uky‚x 2&,sfeuksI;wfju }kjk {kkjd ;qXe dk
mnkgj.k ns[ksa½A fcanq mRifjorZu ds lkFk] xq.klw= dh iwjh lajpuk dks cnyk tk
ldrk gS] xq.klw= {ks=ksa dks iyVk tk ldrk gS; ,sls mRifjorZu dks fMyhV] MqIyhdsV
;k VªkalyksdsVsM Øksekslksey mRifjorZu dgk tkrk gSA mRifjorZu ekrk&firk
¼teZyu mRifjorZu (Germline mutations)½ ls fojklr esa fey ldrs gSa ;k fdlh
O;fä ¼dkf;d mRifjorZu (somatic mutations)½ ds thou esa çkIr fd, tk ldrs
gSa] ckn okys i;kZoj.kh; dkjdksa tSls fd iSjkcSaxuh (UV) fofdj.kksa vkSj jlk;uksa }kjk
mRiUu gksrs gSaA ;qXedksa esa teZykb mRifjorZu gksrs gSaA pwafd oa'k 'kq: esa ,d vaMs
vkSj ,d 'kqØk.kq ds lay;u ls çkIr gksrk gS] ekrk&firk ds teZykbu mRifjorZu Hkh
mudh larku ds çR;sd U;wfDy;sVsM d¨f'kdk esa ik, tk ldrs gSaA dbZ lkekU; ekuo
jksx mRifjorZu ds dkj.k gksrs gSaA dSla j lcls vke ekuo vkuqoaf'kd jksx gS; ;g dbZ
o`f)&fu;af=r thuksa esa gksus okys mRifjorZu ds dkj.k gksrk gSA dHkh&dHkh dSl a j iSnk
djus okys thu tUe ls gh ekStwn gks ldrs gSa] ftlls O;fä esa dSl a j gksus dh
laHkkouk c<+ tkrh gSA
cgq:irk
DNA vuqØe esa ,d fHkUurk tks tula[;k esa 1% ;k mlls vf/kd dh vko`fÙk ds
lkFk gksrh gS] cgq:irk dgykrh gSA tula[;k esa mPp ?kVuk ls irk pyrk gS fd
,d cgq:irk LokHkkfod :i ls gksrh gS] ;k rks ,d rVLFk ;k ykHkdkjh çHkko ds
lkFkA cgq:irk Hkh mRifjorZu dh rjg ,d ;k ,d ls vf/kd U;wfDyvksVkbM
ifjorZuksa dk gks ldrk gSA fp= 12-8 esa geus ,dy U;wfDyvksVkbM cgq:irk
(Single Nucleotide Polymorphisms) ¼,l,uih½ dk ,d mnkgj.k fn[kk;k gSA bl
ekeys esa ,dy U;wfDyvksVkbM dks ,d vyx U;wfDyvksVkbM }kjk çfrLFkkfir fd;k
tkrk gSA DNA esa lkekU; cnyko ekus tkus ds fy, cgq:irk dkQh lkekU; gSaA
vka[kksa dk jax] ckyksa dk jax vkSj jä ds çdkj tSls yksxksa ds chp dbZ lkekU; varjksa
ds fy, cgq:irk ftEesnkj gSaA gkykafd dbZ cgq:irkvksa dk fdlh O;fä ds LokLF;
ij dksbZ udkjkRed çHkko ugha iM+rk gS] ysfdu buesa ls dqN fofo/krk,a dqN fodkjksa
ds fodkl ds tksf[ke dks çHkkfor dj ldrh gSaA

A A
T T T T
A A A G
T G C G
C C C C
G G

,l,uih ifjorZ A, G
64 fp= 12-8: DNA jTtqd esa ,l,uih
bdkà 12 U;wDyhbd vEy

DNA cgq:irk fo'ks"k :i ls ,l,uih ekuo mRifÙk] fodkl vkSj çkxSfrgkfld çokl
ds iqufuZekZ.k esa ,d 'kfä'kkyh midj.k cu x;kA igys ge ekuo fodkl ds
iqufuZekZ.k ds fy, iqjkrkfRod vkSj iqjkik"kk.kdkyhu lk{;ksa ij fuHkZj jgrs FksA bu
ikjaifjd lk{;ksa ds vHkko esa DNA fo'ys"k.k ekuo fodkl ds iqufuZekZ.k ds fy, ,d
oSdfYid midj.k cu x;kA
mRifjorZu vkSj cgq:irk nks çdkj ds DNA ifjorZ gSaA mRifjorZu vkSj cgq:irk ds
chp eq[; varj tula[;k ds Hkhrj çR;sd çdkj ds :iksa dh ?kVuk dh vko`fÙk gSA
ekuo ykHk ds fy, DNA ifjorZ ds bl Kku dk Qk;nk mBk;k tk ldrk gSA
vk/kqfud ;qx esa vk;qfoZKku ds ftu {ks=ksa esa lokZf/kd rst xfr ls fodkl gks jgk gS
og gS jksxy{k.k vkuqoaf'kdh (clinical genetics) vkSj blds vusd dkj.k gSaA eq[;
dkj.k vk/kkjHkwr vkuqoaf'kdh esa tkus ds foiqy HkaMkj dk [kqy iM+uk gSA ,slk dgk tk
ldrk gS fd lnks"k thu ls lnks"k ,Ut+kbe curk gSA ekuoksa eas yxHkx 2500 jksx
,sls gSa tks izR;{k :i ls ;k vizR;{k :i ls nks"kiw.kZ thu ds dkj.k gksrs gSaA iqVh;
rarqe;rk (cystic fibrosis), e/kqesg ¼Mk;fcVht+ eSfyVl½] vfrjDrnkc (hypertension)
vkfn ,sls jksxksa ds mnkgj.k gSa tks nks"kiw.kZ thu ds dkj.k gksrs gSaA
ekuo vkuqoaf'kd jksxksa dh vlyh izd`fr dks le>us ds fy, fo'ys"k.k dh ekStwnk
rduhdksa dh vksj Hkh xgjh le> ds lkFk&lkFk ekuo thuksa dh lajpuk vkSj izdk;kZsa
dk vf/kd foLr`r Kku gksuk vko';d gSA vusdksa raf=dh; fodkjksa (neurological
disorders) ds fy, lnks"k thuksa dks /kkj.k djus okys xq.klw=ksa dk irk yxkus ds fy,
vkuqoaf'kd bathfu;jh dh rduhd igys ls gh dke esa ykbZ tk jgh gSA la;qä jkT;
vesfjdk esa] iwjs ekuo thukse dks fpfàr djus dk ,d cgqr gh egRokdka{kh dk;ZØe
1990 esa 'kq: fd;k x;k FkkA blds iwjk gksus ds nl lky ckn] blus ,d ,slh laifÙk
dh tkudkjh çnku djuk tkjh j[kk gS tks thu fpfdRlk (therapy) dh ;kstuk
cukus vkSj vkuqoaf'kd fodkjksa ds bykt esa mi;ksxh gSA
D;k DNA :ikarfjr fd;k tk ldrk gS\
vkt iqu;ksZtu DNA VsDuksykWth (recombinant DNA technology) dk ,d u;k
yqHkkouk {ks= lkeus vk;k gSA ftlus vusd cqf)thfo;ksa dk /;ku [khapk gSA bl
VsDuksykWth ds dsUnz esa ,d tho ds DNA vuqØe dks nwljs esa lekfo"V dj ldus dh
{kerk fufgr gSA ;g izpkyu (operation) Dyksfuax (cloning) dgykrh gSA ,d ckj
DNA dk dksbZ [kkl [kaM Dyksu dj fn;k tkrk gS rks blds xq.k vkSj vklkuh ls
vfHkyf{kr (characterised) fd, tk ldrs gSaA izksbUlqfyu igyh izksVhu Fkh ftldk
thu vuqØe fu/kkZfjr fd;k x;k FkkA bldk egRo ijiks"kh (host) tho ¼Dyksfuax
thu ikus okyk½ }kjk bUlqfyu ds fuekZ.k dh pkyw dj ldus dh {kerk esa Nqik gSA
bls e/kqesg ds jksfx;ksa dks fn;k tk ldrk gSA Ård IykfTeukstu lfØ;d (tissue
plasminogen activator or tPA) uked ,d FkDdk (clot) ?kksy nsus okyh ,Ut+kbe dks
vkuqoaf'kdr% bathfu;j fd;k x;k gSA bls vpkud fny dk nkSjk iM+us ds ckn ân;
Ård dks igqapus okyh {kfr dks de djus ds fy, dke esa yk;k tkrk gSA pspd ds
Vhds (smallpox vaccine) dks u;k :i fn;k tk jgk gS rkfd ,slk cnyk gqvk :i
cu lds tks vusd nwljs jksxksa ls izfrj{kk (immunity) ns ldsA ;s jksx eysfj;k ls
ysdj bUQ~yw,Utk rd gSA LokLF; lEcU/kh leL;kvksa dh vkuqoaf'kd bathfu;jh ds
lEHkkO; vuqiz;ksx (potential application) dh lwph lky nj lky c<+rh tk jgh gSA
bl izdkj U;wDyhbd vEyksa egRo u dsoy thou ds jgL; dks le>us esa gS cfYd
bl Kku dks vf/kd vPNs thou vkSj vPNh nqfu;k ds fy, dke esa ykus eas Hkh gSaA 65
[kaM 4 fyfiM v©j U;wfDyd vEy

cks/k iz'u 6
fuEufyf[kr dFku lgh gS ;k xyr bl ij lgh dk ¼ ½ fu'kku yxkb,%
¼d½ U;wDyhbd vEy eas Q+kLQ+ksMkb,LVj ca/krk iM+kslh U;wfDyvksVkbMksa dh 5vkSj
3fLFkfr;kas rd QSyh gksrh gS (lgh@xyr)

¼[k½ DNA esa {kkjd ;qXeu ,sMsuhu] Fkk;ehu vkSj Xokuhu % lkbVkslhu ds chp
gksrk gSA (lgh@xyr)

¼x½ DNA dk izfrd`fr DNA ikWfyejsl }kjk mRizsfjr gksrk gS (lgh@xyr)

¼?k½ DNA esa G : C vkSj A : T vuqikr ;wfuVsa gSa (lgh@xyr)

vkb, vc RNA v.kq dk foLrkj ls o.kZu djsaA

12.6 jkbcksU;wDyhbd vEy (RNA)

tSlk fd geus igys crk;k RNAs 5’→3’ Q+kWQk+ sMkb,LVj ca/k okys
jkbcksU;wfDyvksVkbMksa ds cgqyd gSaA RNAs dh lajpuk yxHkx ges'kk js[kh; (linear)
gksrh gSA RNA esa ekStwn fo"kepØh; ukbVªkstuh {kkjdksa ds eksyh; vuqikr (molar
proportion) ;kuh ,sMsuhu] Xokuhu] ;wjsfly vkSj flLVkslhu i;kZIr :i ls fofHkUu
gksrs gSa vkSj tSlk fd igys le>k x;k Fkk ;s leksyh; (equimolar) ugha gSaA dqNsd
fo"kk.kq (viral) RNA v.kqvkas dks NksM+dj RNA esa U;wDyhbd vEy dk ,d gh jTtqd
gksrk gSA thfor dksf'kdk esa izksVhuksa vkSj ikWfyisIVkbMksa dk fu;a=.k DNA vkSj RNA
}kjk gksrk gS ¼fp= 12-9½ oLrqr% RNAs lwpukRed varj.k (informational transfer)
ds ^^fopksfy,** gSaA RNAs dks rhu eq[; Jsf.k;ksa esa ckaVk x;k gS tks izksVhuksa vkSj
ikWfyisIVkbMksa ds tSola'ys"k.k esa mudh Hkwfedk ij fuHkZj djrk gSA ;s gSa jkbckslkseh
(ribosomal) RNA (rRNA), nwr (messenger) RNA (mRNA) vkSj varj.k (transfer)
RNA (tRNA)A vkb, bu rhu rjg ds jkbcksU;wDyhbd vEyksa ds ckjs esa vkSj v/;;u
djsaA
Raplicated DNA
(Prior to cell division) Cytoplasm

DNA (gene)
RNA synthesis
Primary transcript
RNA

Transfer RNA Messenger RNA Ribosomal RNA

RNA Ribosome
strand subunit
Ribosom

Growing
polypeptide
To protein Finished
synthesis polypeptide

Amino acid pool Polysome

fp= 12-9% dsUnzdh; (nuclear) DNA dk fofHkUu RNAs ls vkSj ikWfyisIVkbMksa ds la'ys"k.k ls
66 lEcU/k dk lajs[kh; fu:i.k (diagrammatic representation)
bdkà 12 U;wDyhbd vEy

12-6-1 jkbckslkseh RNA (rRNA)

RNAs eas jkbckslkseh RNA lcls T;knk ik, tkrs gSa vkSj dksf'kdk esa jkbckslkseksa esa
ekStwn gksrs gSaA dqy RNA dk 66% jkbckslkseh RNA gksrs gSa tks mudh egRoiw.kZ
lajpukRed Hkwfedk dks mtkxj djrk gSA ;s jkbckslkse ds vfuok;Z va'k gS vkSj
jkbckslkseh izdk;Z dks fNUu&fHkUu fd, fcuk bUgsa vyx ugha fd;k tk ldrkA
rRNAs ,dy jTtqd (single strand) okys gksrs gSaA G ls C vkSj A ls U vuqikr
vleku gksrk gS tcfd DNAs eas ,slk ugha gSaA muesa {kkjd ;qXe A : T vkSj G : C
cjkcj vuqikr esa gksrs gSaA fQj Hkh] {kkjd ;qXeksa ds chp gkbMªkstu vkca/k cuus ds
QyLo:i gs;j fiu fdLe ds eksM+ cu tkrs gSa ¼tSlkfd rRNAs eas Hkh ik, tkrs gSa½
gkbMªkstu vkca/ku (hydrogen bonding) vkSj rRNA dh ,dy jTtqd izd`fr dk
lkewfgd urhtk ;g gksrk gS fd bldk vkdkj fof'k"V@vfu;fer f=&fo (three
dimensional) gks tkrk gSA ;gh og lgh&lgh dkj.k gS ftldh otg ls rRNA ds
ekeys esa X-fdj.k lajpuk fo'ys"k.k vkSj Hkh T;knk fod`r gksrk gSA {kkjd vuqØe.k
(base sequencing) gh ,dek= ,slk rjhdk gS ftlls bldh lajpuk dks [kkstk tk
ldrk gSA ysfdu cgqr yEch Ük`a[kyk ¼1520&3000 U;wfDyvksVkbM½ ds dkj.k ;g
izØe (process) O;ogkj eas yk;k tkus okyk ugha jgrkA bu lc rF;ksa ds ckotwn
lw{ethofoKkuh (microbiologist) rRNA lajpuk ds jgL; ds lqy>kus dk iz;kl djrs
jgrs gSa vkSj dqN ,UVvehck dksykbZ RNA Ük`a[kykvksa ds fy, vuafre vuqØe Kkr gSaA izR;sd ,sehuks vEy dks
ysfdu gekjs ikl Hkh rRNA f=foe lajpuk dh dksbZ Bksl /kkj.k (idea) ugha gSaA dksM djus ds fy, ,d
rRNA dh lgh&lgh Hkwfedk ekywe ugha gS ysfdu ikWfyiSIVkbM la'ys"k.k ds LFky gSa rhu {kkjd vuqØe dh
vkSj nwr RNA ds lkFk dkEIysDl cukrs gSaA vko';drk gSA mRNA
ij ;g rhu {kkjd
12-6-2 nwr RNA (mRNA) vuqØe dksMkWu dgykrk
gS%
jkbckslkseh RNA dh vis{kk nwr RNAs dgha T;knk NksVs gksrs gSa vkSj ikWfyisIVkbM
la'ys"k.k esa lfØ; RNA ;s gh gSA dksfMr DNA ls ^^lans'k** ys tkus ds dkj.k budk G
G
uke nwr RNA iM+k vkSj ;s ikfyisIVkbMksa ds la'ys"k.k dk funsZ'ku djrs gSaA nwr RNA U
thu dk iwjd (complementary) gS vkSj blesa {kkjdksa dk f=d (triplet) ,d fo'ks"k C
,sehuksa vEy ds fy, dksM gS vkSj dkMkWu dgykrk gSA mRNA dh jh<+ ij dksMkWu dk A
G
vuqØe fo'ks"k ikWfyisIVkbM ds la'ys"k.k dk funsZ'ku djrk gSA nwr RNAs dh U
Ük`a[kyk&yEckbZ vkSj vkf.od Hkkj (molecular weight) eas vR;f/kd varj gksrk gS tSlk G
C
fd fofHkUu yEckbZ ds fofHkUu ikfyisIVkbMksa dh la[;k ls vkSj dksf'kdk }kjk la'ysf"kr
U
vkf.od Hkkj ls irk pyrk gSA bu fofHkUurkvksa (variations) dk dkj.k vuqØe dh C
vleku yEckbZ Hkh gS tks fdlh Hkh ,sehuks vEy ds fy, dksM ugha djrh ysfdu C

fof'k"V izksVhuksa ds la'ys"k.k dk fu;a=.k djrh gSA vxzx vuqØe (leader

sequences) okys ;s {kkjd vuqØe mRNA ds 5 fljs ij gksrs gSaA nwr RNA dksf'kdk izR;sd tRNA ,d
esa rsth ls fuEuhd`r (degraded) gks tkrk gS blfy, tSlh Hkh vkSj tc Hkh vf}rh; rhu {kkjd
vko';drk iM+s rktk vkiwfrZ gksuh t:jh gSA nwr RNA dk la'ys"k.k RNA ikWfyejsl vuqØe Hkh ys tkrk gS
dgykus okyh ,Ut+kbe }kjk DNA ls gksrk gS vkSj thu ¼DNA v.kq½ ls vkuqoaf'kd tks mRNA ij dksMkWu
dksM (genetic code) mRNA ij vuqysf[kr (transcribed) gksrk gSA mRNA ds dk iwjd gksrk gS vkSj
la'ys"k.k dk ;g izØe vuqys[ku (transcription) dgykrk gSA ge vxyh bdkà esa izfr dksMkWu (anticodon)
ds uke ls tkuk tkrk
blds ckjs esa laf{kIr ppkZ djsaxsA
gSA
12-6-3 varj.k RNA (tRNA)

varj.k RNA dksf'kdk eas ,sehuksa vEy ifjogu ra= esa Hkkx ysrk gSA ;g ra= O;f"V
(individual) ,sehuks vEy dks izksVhuksa ¼ikfyisIVkbMksa½ ds la'ys"k.k LFky rd ys tkrk 67
[kaM 4 fyfiM v©j U;wfDyd vEy
gSA ;s NksVs v.kq gksrs gSaA izR;sd v.kq 60&95 U;wfDyvksVkbM gksrs gSaA ;s ,dy jTtqd
okys gksrs gSa ysfdu tRNA esa iwjd {kkjd ;qXeu ,sMsuhu % ;wjsfly vkSj Xokuhu %
lkbVkslhu] bruk O;kid gksrk gS fd ;g ,d vf}rh; Dyksoj&iÙkh tSlh lajpuk cu
tkrh gS ¼fp= 12-10½
3'
OH

A
C CCA triplet
C
A
5' G C
G C
G U
C G
G C
U U
G C
A G G C C U A
G A U C C G U G
C
G C
C C C C
G G G
A G C G C
G

C
A
G G G
C
A
U
C G

C G

C G
U
U
G C

Anticodon

¼d½ ¼[k½

fp= 12-10% ,sysfuu ds fy, varj.k RNA (tRNA) ¼d½ ,d vR;f/kd O;oLFkkRed fu:i.k
(schematic represention) gS rkfd O;kid {kkjd ;qXeu ds dkj.k f}&jTtqd {ks=
dh ekStwnxh Li"V gks lds] vlkekU; {kkjd [kkyh ldZy ds :i esa fn[kk, x, gSa]
¼[k½ varj.k RNA dk ekWMy: bldk izfrdksMkWu {kkjd ds fljs ij gksrk gS bls yky
jax esa fn[kk;k x;k gS; vkSj LFkku tgka ,sehuks vEy ca/ku lkbV dks ihys jax esa
fn[kk;k x;k gS

;g ns[kk x;k fd lHkh tRNA v.kqvksa ds fy, vk/kkjHkwr f=foe foU;kl ,d gh tSlk
gksrk gSA tRNA {kkjd vuqØe dk lcls vlk/kkj.k y{k.k vlkekU; {kkjdksa dk gksuk
gSA vlkekU; {kkjdksa dk vFkZ gS A, G, C ;k U dks NksM+dj vU; {kkjdA ;s vlkekU;
{kkjd uhps fn[kk, x, gSaA
O O
H3C N
N N
HN

N H N N
N
Ribose
Ribose
Inosine (I) 1-Methylinosine (MeI)

O O
H3C N
N N
HN
H3C H2N N
N N N N
Ribose
CH3 Ribose

68 N(2)-Dimethylgunonosine (DiMeG) 2-Methylgunonosine (MeG)

bdkà 12 U;wDyhbd vEy

O O O
CH3 OH
HN HN HN

O N O N OH O N

Ribose Ribose Ribose

Ribothymidine (T) Dihydrouridine (DiHU) Pseudouridine

varj.k RNA esa vlkekU; {kkjd : varj.k RNA esa ik, x, dqN vlkekU; {kkjdksa dh lajpuk,a

vlkekU; {kkjd orZeku ikWfyU;wfDyvksVkbMksa ds ,Ut+kbeh :ikarj.kksa (modication) ls

curs gSA bu vlkekU; {kkjdksa dh Hkwfedk dks vHkh rd iwjh rjg ugha le>k x;k gSA
buesa ls vusd {kkjdksa esa] {kkjd iwjd {kkjd ;qXe cukus dh {kerk gksrh gSA vkSj ;s
tRNA dh f=foe lajpuk esa fo?kVu iSnk dj ldrs gSaA bl rjg os dhVksa (keto) vkSj
,sehuksa lewgksa dks izdV dj nsrs gSa tksfd mRNA, jkbckslkseksa ;k ,Ut+keksa ls f}rh;d
(secondary) vkca/k cukrs gSaA

fdlh Hkh O;fDr dks ;g vk'p;Z gks ldrk gS fd tRNA fdl izdkj fdlh fo'ks"k
,sehuksa vEy dks ikWfyisIVkbM la'ys"k.k LFky rd yk ikrk gSA oLrqr% ;g ,d
nqHkkf"k, ds :i esa dke djrk gS tSlk fd vyx&vyx Hkk"kk cksyus okys nks O;fD;ksa
ds chp ,d nqHkkf"k, dh vko';drk iM+rh gSA nqHkkf"k;k nksuksa ds chp laizs"k.k
(communicate) djrk gS vkSj bl izdkj mUgsa ,d nwljs dks le>us ;ksX; cukrk gSA
tRNA nks ^^Hkk"kkvksa** ls fucV ldrk gS ;s gSa vkuqoaf'kd dksM vkSj ikWfyisIVkbMA esa
vkuqoaf'kd Hkk"kk dksMkWu esa vfHkO;fDr dh tkrh gS vkSj tRNA esa {kkjdksa dk iwjd
f=d gksrk gS ftls izfrdksMkWu dgrs gSa ¼fp= 12-10½A blh dh otg ls ;g dksMkWu
dks igpku ldrk gSA 3Nksj jkbcksl ;wfuV ij OH lewg okys tRNA v.kq dk nwljk
Hkkx fo'ks"k ,sehuks,fly ;wfuV dks ,LVj vkca/k }kjk layXu dj ldrk gSA bl rjg
,d [kkl ,sehuks vEy okys v.kq dk ikWfylksl ikWfyisIVkbM la'ys"k.k LFky ij
mRNA ds dksMkWu ds lkFk lajs[k.k (alignment) dj fn;k tkrk gSA ml [kkl ,sehuksa
vEy dk fu'p; izfrdksMkWu djrs gSaA ;g lkjk izØe LFkkukarj.k (translation)
dgykrk gSA vkidks bl ckr dk /;ku j[kuk pkfg, fd dksMkWuksa dh vf}rh; Jsf.k;ka
(unique series) ikWfyisIVkbM Ük`a[kyk dks ,sehuks vEy vof'k"V ds dsoy mrus gh
vf}rh; vuqØe ds lkFk c<+us nsrh gSa D;ksafd dksMkWuksa vkSj izfrdksMkWuksa ds chp gksus
okyk ;qXeu dsoy ,d gh vuqØe gksus ns ldrk gSA

vkb, le>rs gSa fd ,sehuks vEy tRNA ds lkFk dSls tqM+rk gSA

tRNA ls ,sehuks vEy ds lkFk ca/ku dh fØ;kfof/k

DNA xBu ds leku] ,Vhih (ATP) ,sehuks vEy dks tRNA ls tksM+us ds fy, igyk
dne mBkrk gSA ;g çfØ;k ,sehuks,fly& tRNA flaFksVsl (aminoacyl-tRNA
synthetase) uked ,atkbe }kjk mRçsfjr gksrh gSA igys pj.k esa] ,sehuks vEy dk
dkcksZfDly lewg ,Vhih (ATP) ij vkØe.k djrk gS vkSj ,sfly,sfMukbysV cukdj
dkcksZfDly lewg dks lfØ; djrk gSA nwljs pj.k tRNA ds 3' OH lewg
,sfly,fMukbysV ds dkc¨Zfuy lewg ds lkFk ukfHkdLusgh vkØe.k djrk gS] ftlls
prq"Qydh; e/;orhZ curk gSA var esa] ,sehuks,sflky tRNA rc curk gS tc ,,eih 69
[kaM 4 fyfiM v©j U;wfDyd vEy
(AMP) dks prq"Qydh; e/;orhZ ls fu"dkflr dj fn;k tkrk gSA lHkh pj.k
,atkbe ds lfØ; LFky ij gksrs gSaA çR;sd ,sehuks vEy dk viuk,sehuks,sfly tRNA
flaFksVst gksrk gSA çR;sd flaFksVsl esa nks fof'k"V ca/ku LFky gksrs gSa] ,d ,sehuks vEy
ds fy, vkSj ,d tRNA ds fy, tks ml ,sehuks vEy dks ogu djrk gSA bl iwjh
çfØ;k dk çLrkfor fØ;kfof/k

uhps fn[kk;k x;k gS:

O O O O

R HC C O- + HO P O P O P O adenosine
+ OH OH OH
NH 3
Adenosine-5'-triphosphate
(ATP)
O O O O H2O
- H3PO 4
R HC C O P OH + HO P P O
+ -
NH 3 O OH OH
3'
HO ACC
3' OH group of tRNA
tRNA
5'
O-
O- O 3'
R CH CH O ACC
R CH C O P OH +
tRNA
3' - H 3N 5'
+ O
H 3N O ACC
tRNA
5'

vkb, vc ge tho/kkfj;ksa esa vkuqoaf'kd dksM (genetic code) dk la{ksi eas o.kZu
djrs gSaA

12.7 vkuqoaf'kd dksM

ge bl bdkbZ esa dksMkWu (codon) izfrdksMkWu (anticodon) vkSj dksMksa (codes) tSls
'kCnksa dk iz;ksx djrs jgs gSaA vc ;g mi;qDr gksxk fd bu 'kCnksa dh lgh&lgh
ifjHkk"kk nh tk,A vkuqoaf'kd inkFkZ DNA v.kq gksrk gS ¼dsoy RNA fo"kk.kqvksa viruses
dks NksM+dj tgka RNA gh vkuqoaf'kd inkFkZ gS½A vc ;g lkfcr gks pqdk gS fd
vkuqoaf'kd tkudkjh DNA esa {kkjdksa ds fof'k"V vuqØeksa (sequences of bases) ds
:i esa ys tkbZ tkrh gS ftUgsa dksMkWu (codon) dgrs gSaA DNA ds fofHkUu [kaM thuksa
ds :i esa izdk;Z djrs gSa ;kuh fd ,sehuks vEyksa ds vuqØe dks fofufnZ"V djds
izksVhuksa ds fy, dksM djrs gSaA DNA ;k blds RNA vuqys[k (transcript) ¼vFkkZr~
mRNA½ esa {kkjdksa ds vuqØe vkSj ,sehuks vEyksa ds }kjk fofufnZ"V izksVhuksa esa ,sehuks
vEyksa ds vuqØe ds chp ds laca/k gS] og vkuqoaf'kd dksM dgykrk gSA

vki tkurs gh gSa fd izksVhuksa esa 20 fHkUu&fHkUu ,sehuks vEy gksrs gSa] tks DNA v.kq esa
ekStwn pkj {kkjdksa }kjk dksMr gksrs gSaA ;g Li"V gS fd vxj ,d {kkjd ,d ,sehuks
vEy ds fy, dksfMr djrk gS] rks dsoy pkj ,sehuks vEyksa dks dksfMr fd;k tk
ldrk gSA lk/kkj.k xf.kr ls irk pyrk gS fd vxj nks {kkjdksa dk la;kstu ,d
70
,sehuks vEy ds fy, dwVys[ku djrk gS] rks bl izdkj ds ;qXeksa (pairs) dh vf/kdre
bdkà 12 U;wDyhbd vEy

la[;k lksyg ¼;kuh 42½ gksrh gSA izksVhuksa esa ik, tkus okys chl ,sehuksa vEyksa ds fy,
iz;kZIr ugha gSA ;g vuqHko fd;k x;k fd U;wure dksM lkbt {kkjdksa dh f=d
(triplet of bases) gksxhA pkj {kkjdksa ls cuus okys fofHkUu f=dksa dh la[;k 64 gksrh
gS ¼;kuh ds 43½] tks lHkh ,sehuks vEyksa dks dksfMr djus ds fy, i;kZIr gSA ckn esa
vkuqoaf'kd iz;ksxksa ls bl ckr dh iqf"V gqbZ fd okLro esa vkuqoaf'kd dksM {kkjdksa dk
f=d gS% rhu fudVorhZ U;fDyvksVkbMsa ,d ,sehuks vEy dks fofufnZ"V djrh gSaA igys
igy ftl dksMkWu dh igpku dh xbZ og UUU Fkk tks Qsfuy&,sykfuu ds fy,
dksfMr djrh gSaA
vkuqoaf'kd dksM esa dqN vfHky{k.k gksrs gSa tSls fd vufrO;kih (non-ooverlaping)
vkSj viàkl (degeneracy)A vufrO;kih ls gekjk ;g eryc gS fd dksbZ Hkh {kkjd
,d f=d ¼dksMkWu½ dk va'k gks ldrk gS vkSj nwljs dksMkWu esa dke esa ugha yk;k
tkrkA bl rjg izR;sd {kkjd dk dsoy ,d ckj ^^okpu** gksrk gS ;k dfg, ,d gh
ckj ^^i<+k** tkrk gSA

1 2 1 1 2

A G U C G U A G U C G U
3
ovelapping codon non-ovelapping codon
vfrO;kih dksMkWu vufrO;kih dksMkWu

viàkl dk vFkZ gS ,d ,sehuks vEy dk ,d ls vf/kd f=d }kjk dwVys[ku fd;k

tkukA dsoy esFkkuhu vkSj fVªIVksQsu ,d vdsys f=d }kjk dksfMr gksrs gSa] tks Øe'k%
AUG vkSj UGG gSaA ckdh lkjs ,sehuks vEyksa ds fy, ,d ls vf/kd f=d }kjk dksfMr
gksrs gSaA ysfdu ;g /;ku nsus dh ckr gS fd dksbZ Hkh f=d dsoy ,d gh ,sehuks vEy
dks dksfMr djrk gSA blds vykok] dksbZ Hkh fn;k x;k f=d lHkh tkfr;ksa ¼Li'kht½
esa mlh ,sehuks vEy dks dksfMr djrk gSA dsoy ekbVksdkWfUMª;k (mitochondria) esa
izksVhu tSo la'ys"k.k bldk viokn gS tgka NksVh&NksVh fHkUurk,a ns[kus esa vkrh gSaA
bl izdkj lkfoZd (universal) ugha gS ysfdu yxHkx lHkh tkfr;ksa ij ykxw gksrk gSA
bls ^ekud** (standard) vkuqoaf'kd dksM ds uke ls iqdkjk tkrk gS vkSj ;g lkj.kh
12-3 esa fn[kk;k x;k gSA
lkj.kh 12-3 ^^ekud** vkuqoaf'kd dksM vkSj dksMkWu fu/kkZjk (assignments)

izFke f}rh; {kkjd r`rh; {kkjd

{kkjd
U C A G

UUU UCU UAC UGU U

Qsfuy&,sykfuu lsjhu Vkbjkslhu flLVhbu
UUC UUC UAC UGC C
U Qsfuy&,syehu lsjhu Vkbjkslhu flLVhbu
UUA UCA UAA ¼fojke½ UGA ¼fojke½ A
Y;wlhu lsjhu CT* CT*

UUG UGC UAG ¼fojke½ UGG G

Y;wlhu lsjhu CT* fVªIVksQkWu 71
[kaM 4 fyfiM v©j U;wfDyd vEy

CUU CCU CAU CGU U

Y;wlhu izksyhu fgLVhMhu vkftZuhu
CUC CCC CAC CGC C
C Y;wlhu izksyhu fgfLVMhu vkftZuhu
CUA CCA CAA CGA A
Y;wlhu izksyhu XywVSehu vkftZuhu
CUG CCG CAG CGG G
Y;wlhu izksyhu XywVSehu vkftZuhu
AUU ACU AAU AGU U
vkblksY;wlhu fFkzvkWuhu ,sLisjkthu lsjhu
AUC ACC AAC AGC C
A vkblksY;wlhu fFkzvkWuhu ykblhu vkftZuhu
AUA ACA AAA AGA A
vkblksY;wlhu fFkzvkWuhu ykblhu vkftZuhu
AUG ¼vkjaHk½** ACG AAG AGG G
lpeqp esa izdk;kZRed esFkk;ksuhu fFkzvkWuhu ykblhu vkftZuhu
(functional) vkuqoaf'kd
;wfuV] thu ;k leikj G GUU GCU GAU GGU U
(cistron) og gS] tks ,d osyhu ,sykuhu ,LikfVZd vEy Xykblhu
ikWfyisIVkbM Ük`a[kyk ds GUC GCC GAC GGC C
la'ys"k.k dks fofufnZ"V
osyhu ,sykuhu ,LikfVZd vEy Xykblhu
(specify) djrk gSA ;kn
dhft, fd dqN izksVhusa GUA GCA GAA GGA A
,dy (single) osyhu ,sykuhu XywVSfed vEy Xykblhu
ikWfyisIVkbM Ük`a[kyk dh GUG GCG GAG GGG G
cuh gksrh gSaA tcfd
osyhu ,sykuhu XywVSfed vEy Xykblhu
nwljh esa ,slk ,d ls
vf/kd le:i * dksMkWu CT Ük`a[kyk&lekiu ds fy, ,d ladsr dksMkWu gSA
(identical) ;k fHkUu ** AUG LFkkukarj.k esa Ük`a[kyk izkjaHku ds fy, ,d ladsr ds :i esa izdk;Z djrk gSA
Ük`a[kyk,a gksrh gSa] tks /;ku nhft, fd dksM mRNA ds fy, fn, x, gSaA DNA esa] U dk LFkku T ysxkA
vlgla;kstd
ikjLifjdfØ;kvksa (non- vkt gesa lHkh ,sehuks vEyksa ds fy, lHkh dM+ks dk irk gS ¼lkj.kh 12-3½A pkj {kkjdksa
covalent interactions) ls 64(43 = 64) lEHkkfor f=dksa esa ls dsoy 61 f=d fof'k"V ,sehuks vEyksa ds fy,
mi&;wfuVs (subunits) dksM djrs gSaA UAA, UAG vkSj UGA uked nwljs rhu f=d fdlh Hkh ,sehuks vEy
}kjk vki esa ca/kh jgrh
ds fy, dksM ugha djrs gSaA ;s Ük`a[kyk lekiuksa ;k fojke ladsrksa ds :i esa dk;Z djrs
gSaA vxj mi&;wfuVsa
jklk;fud :i ls fHkUu gSaA f=d AUG ¼esFkk;ksuhu ds fy, dksM½ izkjaHkd dksMkWu dh rjg Hkh dke djrk gS
gksa] rks laiw.kZ izksVhu dks ;kuh fd ubZ ikWfyisIVkbM dks la'ys"k.k 'kq: djus ds fy, dke vkrk gSA vkb,] bu
fofufnZ"V djus ds fy, dksMkWu dh dqN foLrkj ls ppkZ djrs gSaA
,d ls vf/kd leikjksa
dh vko';drk iM+rh gSA izkjaHku dksMkWu

mRNA vkerkSj ij cgqleikjh; (polycistronic) gksrk gS vFkkZr] ;g vusd

fHkUu&fHkUu izksVhuksa ds la'ys"k.k ds fy, lans'k ys tkrk gSA blfy, ;g t:jh gS fd
blesa Hkh ^^vkjaHk** ;k ^^fojke** ladsr gksa rkfd izR;sd izksVhu ds fy, lans'k nwljh
72
bdkà 12 U;wDyhbd vEy

izksVhu ds fy, lans'k ls vPNh rjg fu/kkZfjr dh gqbZ vkSj i`Fkd fd, gq, gksA
tSlkfd lkj.kh 12-3 esa fn[kk;k x;k gSA vkuqoaf'kd dksM esa ,sls ladsr t:j gksrs gSaA
tc f=d AUG lans'k ds vH;arj ;k dfg, Hkhrjh Hkkx esa gksrk gS] rks esFkk;ksuhu ds
fy, dksMkWu ds :i esa vkSj tc lans'k ds 'kq: esa gksrk gS] rks Ük`a[kyk izkjaHku ds fy,
dksMkWu ds :i esa dk;Z djrk gSA ckn okys ekeys esa ;g eqDr esFkkuhu ds fy, ugha
cfYd N-QkWfeZy esFkk;ksuhu ds fy, dksM djrk gSA
O O
H C NH CH C OH H2N CH C OH
O (CH2) (CH2)
S S
CH3 CH3
N-QkWfeZy esFkk;ksuhu (FMet)(FMet)
N-Formylmethionine esFkk;ksuhu (Met)
Methionine (Met)

esFkk;ksuhu ds fy, nks rjg ds tRNA gksrs gSa ftuds uke & tRNAFMet vkSj tRNAMetA
nksuksa eas ,d ls izfrdksMkWu gksrs gSa ysfdu Øe'k% QkWfeZy&esFkk;ksuhu vkSj esFkk;ksuhu
ds fy, fof'k"V gksrs gSaA os mRNA, ij AUG dksMkWu ds lkFk Øe'k% lans'k ds 'kq: esa
vkSj vH;arj esa la;kstu djrs gSaA blds dkj.k izR;sd uotkr ikWfyisIVkbM (nascent
polypeptide) Ük`a[kyk ds N-VfeZuy ij esFkk;ksuhu vof'k"V (residue) gksrk gSA dqN
ekeyksa esa f=d GUG vkjaHk ladsr ds :i esa dk;Z djrk gSA ;wdSj;ksVksa] izkjaHkd
esFkk;ksuhu QkWfeZyhd`r (formulated) ugha gksrh gSA

lekiu dksMkWu%
rhu f=d ,sls gSa] tks fdlh Hkh ,sehuks vEy ds fy, dksM ugha djrs gSaA ;s gS&
UAA, UAG vkSj UGAa ;s lekiu ;k fojke ;k fueqZDr (release) ;k vuFkZd
(nonsense) dkMkWu dgykrs gSaA ;s dksMkWu fdlh Hkh ,sehuks,sfly&tRNA (aa-tRNA)
}kjk ugha i<+s tkrs cfYd fueqZfDr dkjd (release factors) dgykus okyh fof'k"V
izksVhuksa }kjk LFkkukarj.k (translation) esa mi;qDr voLFkk ¼lekiu½ ij igpkus tkrs gSa
ftlds QyLo:i ,d laiw.kZ cu pqdh ikWfyisIVkbM Ük`a[kyk fueqZDr gksrh gSA ;g
ns[kk x;k gS fd dqN ekeyksa esa] lekiu dksMkWu vdsys gh dk;Z djrk gS tcfd nwljs
ekeyksa esa nks vuqØfed lekiu dksMkWu Ük`a[kyk lekiu dk dke dgrs gSa
¼fp= 12-11½A
Human hemoglobin a chain mRNA:

AAAUACCGUUAAGCU...

E. coli lactose represor mRNA:


GAAAGCGGCGAGUGACCGCAAGGCAAUUAA

MS2 "A" Protein mRNA:


CGGCUCUCUAGAUAGAGCCUCAA...

MS2 coat protein mRNA:


UCCGGCAUCUACUAAUAGACGCCG...

fp= 12-11 eksVs v{kj okyk f=d lekiu dksMkWuksa dks n'kkZrk gS 73
[kaM 4 fyfiM v©j U;wfDyd vEy
cks/k iz'u 7

vkuqoaf'kd dksM ds ckjs esa uhps fn, x, dFkuksa esa ls dkSu&lk lp ugha gS\
d) gj dksMkWu esa rhu U;wfDyvksVkbM gksrs gSaA
[k½ izR;sd dksMkWu dsoy ,d gh izdkj ds ,sehuks vEy ds fy, dksM djrk gSA
x½ dksMkWu mRNA ij ys tk, tkrs gSaA
?k½ izR;sd izdkj ds ,sehuks vEy ds fy, ek= ,d dksMkWu gksrk gSA

vxyh bdkbZ esa vki lh[ksaxs fd dSls DNA çfr—fr uked ,d çfØ;k }kjk DNA
,d u;k DNA v.kq mRiUu djus esa enn djrk gS] Bhd mlh rjg] tgka ewy DNA
ij çR;sd jTtqd dks nksgjk;k tkrk gSA uoxfBr DNA jTtqd ewy DNA jTtqd
vkSj ,d nwljs ds iwjd gSaA DNA çfrys[ku uked ,d çfØ;k }kjk jkbcksU;wfDyd
vEy dks la'ysf"kr djus esa Hkh enn djrk gS tks DNA çfr—fr ds leku gS] ;g Hkh
ml bdkbZ esa 'kkfey fd;k tk,xkA çksVhu la'ys"k.k dk foLrkj ls o.kZu Hkh bdkbZ
13 esa fd;k x;k gSA

12.9 lkjka'k
 U;wDyhbd vEy cM+s vkSj tfVy ¼dkEysDl½ tSo v.kq gSaA os thfor dksf'kdk ds
dsUnzd vkSj dksf'kdk nzO; (cytoplasm) eas jkbckslkseksa ij ik, tkrs gSaA os
vkuqoaf'kdk ds fy, mÙkjnk;h gS vkSj thou ds ckjs esa vusdksa iz'uksa dk mÙkj
buesa fey tkrk gSA

 U;wDyhbd vEy nks izdkj ds gksrs gS&fMvkWDlhjkbcksU;wdyhbd vEy (DNA) vkSj

jkbcksU;wdyhbd vEy (RNA)

 U;wDyhbd vEy ikWfyU;wfDyvksVkbM gksrs gSa vkSj O;f"V (individual)

U;wDyhvksVkbM ,dyd ,d nwljs ls 5'→3' Q+kLQ+ksMkb,LVj ca/krk }kjk tqMs+
jgrs gSaA U;wfDyvksVkbM vius vki esa ,d ukbVªkstuh {kkjd] ,d isUVksl 'kdZjk
¼Q~;jw suksl :i esa½ vkSj ,d Q+kLQ+sV ;wfuV ls curs gSaA isUVksl 'kdZjk vkSj
ukbVªkstuh {kkjd dk la;kstu (combination) U;wfDyvkslkbM dgykrk gSA bl
izdkj U;wfDyvksVkbM vkerkSj ij 'kdZjk dh 5fLFkfr ij U;wfDyvkslkbMksa ds
Q+kLQsV ,LVj gksrs gSaA

 DNA ,d lkoZHkkSfed vkuqoaf'kd inkFkZ gSA gekjs i`Foh ij lc izdkj ds thoksa

dh mRifÙk mUgha ls gqbZ gS mUgha ds dkj.k lcdk vfLrRo Hkh gSA DNAs esa pkj
ukbVªkstuh {kkjd gksrs gSa&nks I;wjhu ftuds uke gSa ,sMsuhu (A) vkSj Xokuhu (G)
rFkk nks fifjfeMhu ftuds uke lkbVkslhu (C) vkSj Fkk;ehu (T) gSaA DNA esa
fMvkWDlhjkbcksl uked isUVksl 'kdZjk gksrh gSA

 bl izdkj DNA v.kq dk vkf.od jh<+ Q+kLQ+ksMkb,LVj vkca/kksa ls vkil esa tqM+h
gqbZ fMvkWDlhjkbcksl ;wfuVksa dh ,d Js.kh gSaA {kkjd bl jh<+ ls iz{ksfir gksrs gSaA
74
bdkà 12 U;wDyhbd vEy

 izR;sd DNA dh fof'k"Vrk {kkjdksa ds vuqØe vkSj vkf.od jh<+ dh yEckbZ ls

curh gSA vkuqoaf'kd tkudkjh lkekU;r;k lehiLFk (contiguous) {kkjdksa ds
f=d ds :i esa dksfMr gksrh gSaA

 dksf'kdk dsUnzdksa eas DNAs nf{k.kkorhZ f}dqaMfyfu;ksa ds :i esa gksrs gSa ftleas
{kkjd vH;arj esa iz{ksfir jgrs gSa vkSj ,d jTtqd ij fLFkr {kkjd ls nwljs
jTtqd ds {kkjd ds chp gkbMªkstu vkca/k LFkkfir gks tkrs gSaA {kkjd ;qXeu
ges'kk gh A vkSj T rFkk C vkSj G ds chp gksrk gSA ,sMsuhu vkSj Xokuhu vkil
esa nks gkbMªkstu vkca/kksa ls tqMs+ jgrs gSa tcfd Xokuhu vkSj lkbVkslhu rhu
gkbMªkstu vkca/kksa ls tqMs+ jgrs gSaA nwljs vfHkfØ;k,a Hkh gSa tks tyfojkxh vkSj
fpfrdj.k vfHkfØ;k,a dgykrh gSaA ;s nksuksa gh izeq[k :i ls f}dqaMfyuh ds
LFkkf;Ro ds fy, mÙkjnk;h gSA

 DNA izfrd`fr dgykus okys izØe }kjk DNAs u;k] ,dne vius tSlk DNA
v.kq mRiUu djus esa enn ns ldrs gSa tgka iS=d DNA ij izR;sd jTtqd
izfrd`r (replicated) gksrk gSA u,&u, cuus okys jTtqd iSr`d DNA jTtqdksa ds
fy, vkSj ,d nwljs ds fy, iwjd gksrs gSaA vuqys[ku dgykus okys izØe }kjk
DNA, jkbcksU;wDyhbd vEy ds la'ys"k.k esa Hkh lgk;rk nsrs gSaA ;g izØe
izfrd`fr tSlk gSA

 jkbcksU;wDyhbd vEy nwljs U;wDyhbd vEy gSa ftuesa ukbVªkstuh {kkjd&,sMsuhu]

Xokuhu] lkbVkslhu vkSj ;wjsfly gksrs gSaA RNA {kkjd esa] ;wjsfly Fkk;lhu dks
izfrLFkkfir djrh gS ;kuh mldh txg ys ysrh gS tks dsoy RNA esa gksrh gSaA
blds vykok RNA eas isUVksl 'kdZjk fMvkWDlhjkbcksl dh ctk; jkbcksl gksrh
gSA bl izdkj RNAs esa ikWfyjkbcksU;wfDyvksVkbM gksrs gSa ftuesa
ekWuksU;wfDyvksVkbM ,d nwljs ls 5’→3’ Q+kLQ+ksMkb,LVj vkca/kksa }kjk layXu
jgrs gSA

 ikWfyisIVkbM la'ys"k.k eas RNAs }kjk fuHkkbZ tkus okyh Hkwfedk ds vk/kkj ij
rhu izdkj RNAs gksrs gSa&jkbckslkseh RNA (rRNA), nwr RNA (mRNA) vkSj
varj.k RNA (rRNA)A RNAs lkekU;r;k ,dy js[kh; (single linear) jTtqd
ds :i esa gksrs gSaA rRNAs jkbckslkse esa ekStwn gksrs gSa vkSj ikWfyisIVkbM
la'ys"k.k ds LFky gSaA mRNA vkuqoaf'kd tkudkjh dks dksf'kdk dsUnz es DNA ls
ikWfyisIVkbM la'ys"k.k LFkky rd dkWMksuksa ds :i esa ys tkrs gSaA lkjs RNAs esa
tNAs lcls NksVs gSaA mudk izdk;Z ,sehuks,fly ;wfuVksa ¼lfØf;r ,sehuksa vEyksa½
dks ikWfyisIVkbM ds la'ys"k.k LFky rd ys tkrk gSA

 ekuoksa esa vusd jksx lnks"k thuksa ds dkj.k gksrs gSaA DNA vuqØe dks :ikarfjr
djus ds iz;kl fd, tk jgs gSa rkfd euq"; bu jksxksa ls tq> ldasA

 vkuqoaf'kd dksM mRNA ij {kkjdksa ds f=d (triplet) ds :i esa varfyf[kr

(inscribed) jgrk gSA izR;sd dksM vf}rh; gksrk gS vkSj dsoy ,d gh ,sehuks
vEy ds fy, dksfMr djrk gSA vkuqoaf'kd dksM viáflr (degenerate), vkSj
vufrO;kih (non-overlapping) gksrk gSA ,d dksMkWu AUG gksrk gS tks
ikWfyisIVkbM la'ys"k.k izØe dk 'kqHkkjaHk djrk gSA izkjaHku dksMkWu ds vykok rhu
75
[kaM 4 fyfiM v©j U;wfDyd vEy
nwljs dksMkWu Hkh gksrs gSaA ;s gSa&UAA, UAG vkSj UGA bUgsa izk;% lekiu
(termination) ;k fojke (stop) dksMkWu ds uke ls tkus tkrs gSaA

 ,sehuksa vEyksa dh RNA ds izfr dksbZ ca/kqrk ugha gksrh bUgsa lfØ; djuk iM+rk
gSA lfØ;.k fof'k"V tRNA ds lkFk ,sehuks vEy ds ladqyu }kjk gksrk gSA ;g
izØe ,Ut+kbeksa ds ,d leqPp; }kjk mRizsfjr gksrk gS tks cgqr fof'k"V vkSj
vR;f/kd n{k gksrk gS rFkk ,sehuks,sfly flUFkSVsl dgykrk gSA lfØ;.k izØe ds
fy, ÅtkZ dk L=ksr ATP gksrk gSA

4.10 var eas dqN iz'u

1. U;wDyhbd vEyksa ds izeq[k la?kVu dkSu ls gSa\

2. U;wDyhvkslkbM vkSj U;wfDyvksVkbM D;k gSa\

3. RNA vkSj DNA ds chp izeq[qk varj dkSu ls gSaA

4. DNA fndqaMfyuh; lajpuk dk laf{kIr o.kZu dhft,A f}dqaMfyuh ds LFkkf;Ro ds

fy, dkSu ls cy mÙkjnk;h gS\

5. fofHkUu izdj ds RNA ds uke crkb, vkSj muds izdk;ksaZ dk laf{kIr o.kZu
dhft,A

6. vkuqoaf'kd dksM dk D;k egRo gS\

7. dksMkWu vkSj izfrdksMkWu 'kCnksa ls vki D;k le>rs gSa] la{ksi esa Li"V dhft,A

8. izkjaHku vkSj lekiuu dksMkWu ds egRo dks mnkgj.k lfgr le>k,A

4.11 mÙkj
1. ?k
2. ?k
3. lajpuk,¡ cukb, tSlk fd geus miHkkx 12-3-1-esa fn[kk;k gSA
4. pkj] ;wjsfly
5. iwjd jTtqd esa {kkjdksa dk Øe nwljh iafä esa gS %
5' G G A C A T G C 3'
3' C C T G T A C G 5'

6. d½ lgh] [k½ lgh] x½ lgh] ?k½ lgh

7. ?k½ ,d ,sehuks vEy {kkjdksa ds ,d ls vf/kd f=d }kjk dwVfyf[kr gks ldrk
76 gSA
bdkà 12 U;wDyhbd vEy

var esa fn, x, iz'u

1. U;wDyhbd vEy ukbVªkstuh {kkjdksa] isUVksl 'kdZjk vkSj Q+kLQ+sV lewgksa ls cus
gksrs gSaA ;s rhu lewg U;wfDyvksVkbM eas la?kfVr gksrs gSa iqu% 5'→3'
Q+kLQ+ksMkb,LVj ca/kksa (links) }kjk ikWfyU;wfDyvksVkbM Ük`a[kyk eas tqM+s jgrs gSaA
U;wDyhbd vEyksa esa mifLFkr ukbVªkstuh {kkjdksa ds uke gS & ,sMsuhu] Xokuh]
Fkk;ehu] lkbVkslhu vkSj ;wsjflyA U;wDyhbd vEyksa esa ikbZ tkus okyh isUVksl
'kdZjkvksa ds uke jkbcksl vkSj 2-fMvkWDlhjkbcksl gSaA
2. ukbVªkstuh {kkjd ds lkFk isUVksl 'kdZjk ds la;kstu (combination) }kjk cuus
okyk ;kSfxd U;wfDyvkslkbM dgykrk gSA ,slk 'kdZjk ds C-1 vkSj fifjfeMhu
{kkjd ds N-1 ;k I;wjhu {kkjd ds N-9 ds chp lgla;kstd vkca/k }kjk gksrk gSA
ukbVªkstuh {kkjd I;wjhu ;k fifjfefMu dksbZ Hkh gks ldrk gSA isUVksl 'kdZjk ;k
rks jkbcksl vFkok fMvkWDlhjkbcksl gks ldrh gSA blh ds vuqlkj
U;wfDyvkWDlkbM dks jkbcksU;wfDyvkslkbM ;k fMvkWDlhjkbcksU;wfDyvkslkbM dgrs
gSaA U;wfDyvksVkbM U;wfDyvkslkbM Q+kLQ+sV gksrs gSa ;kuh fd isUVkslksa ds Q+kLQs+V
,LVj gksrs gSa ftuls ukbVªkstuh {kkjd layXu jgrs gSaA Q+kLQ+sV ca/k vkerkSj ij
3'@5' fLFkfr;ksa ij gksrs gSaA
3. isUVksl 'kdZjk RNA esa jkbcksl gksrh gS tcfd DNA esa fMvkWDlhjkbcksl gksrh gS%
blds vykok] RNAs esa Fkkbehu ugha gksrh vkSj DNAs esa ;wjsfly ugha gksrhA
blds lkFk&lkFk] DNA eas f}dqaMfyuh gksrh gSa tks nks iwjd U;wDyhbd vEy
jTtqdksa dh cuh gksrh gSaA ysfdu RNA lkekU;r;k U;wDyhbd vEy ds ,dy
jTtqd dk cuk gksrk gSA
4. fØd vkSj okVlu }kjk izLrkfor DNA dh f}dqaMfyuh; lajpuk esa nks iwjd
U;wDyhbd jTtqd gksrs gSaA ;s jTtqd ,d nf{k.kkorhZ dqaMfyuh esa O;kofrZr gq,
gksrs gSaA ukbVªkstuh {kkjd daqMfyuh ds Hkhrjh vksj gksrs gSa tcfd Q+kLQ+sV vkSj
'kdZjk lewg dqaMfyuh ds ckgjh vksj gksrs gSa ¼bls fp= 4-4 esa n'kkZ;k x;k gS½A
bl ekWMy dh rqyuk ,d lfiZy lh<+h ls dh tk ldrh gS ftlesa LVsi
dqaMfyuh ds v{k ds yac gksrs gSaA Åij ds ekWMy esa] ukbVªkstuh {kkjdksa ds ry
Hkh dqMfyuh v{k ds yEc gksrs gSaA f}dqMfyuh esa gkbMªkstu vkca/ku nks iwjd
jTtqdksa ds ,sMsuhu % Fkk;ehu vkSj Xokuhu % lkbVkslhu ds chp gksrk gSA
f}dqaMfyuh ds LFkkf;Ro ds fy, {kkjdksa ds chp gksus okyh tyfojkxh fpfrdj.k
vfHkfØ;k,a mÙkjnk;h gSaA
5. RNAs rhu izdkj ds gksrs gSaA buds uke gS&jkbckslkseh RNA(rRNA), nwr RNA
(mRNA) vkSj varj.k RNA (tRNA)A vko';drk iM+us ij dksf'kdk dsUnzd esa
la'ysf"kr gksus okys mRNA jkbckslkseksa ij pys tkrs gSa vkSj izksVhu la'ys"k.k esa
,sehuksa vEyksa ds vuqØe ds fy, dks tkudkjh nsrs gSaA rRNAs tksfd jkbckslkseks
ds vfuok;Z va'k gSa] mRNA ls la;ksftr gksdj ikWfyisIVkbM la'ys"k.k ds LFky
cukrs gSaA tRNA tks fd dksf'kdk ds Hkhrj gh vklkuh ls pyus dh {kerk okys
lcls NksVs RNA v.kq gSa] ,sehuksa vEy v.kqvksa dks izksVhu la'ys"k.k ds fy,
jkbckslkseksa rd ys tkrs gSaA
6. Hkkx 12-7 nsf[k,A 77
[kaM 4 fyfiM v©j U;wfDyd vEy
7. dksMkWu % vkuqoaf'kd dksM ,d 'kCn&dks"k gS] og {kkjdksa ds vuqØe
¼U;wfDyvksVkbM {kkjd½ vkSj ,sehuksa vEyksa ds vuqØe ds chp laxrrk nsrh gSA
dksM esa izR;sd O;f"V 'kCn (individual ow rds) rhu U;wfDyvksVkbM {kkjdksa
ls fufeZr gksrk gSA ;s vkuqoaf'kd 'kCn dksMkWu dgykrs gSaA

ÁfrdksMkWu % dksf'kdh; ,sehuks vEyksa ds iqat ls fo'ks"k ,sehuks vEy dk oj.k

(selection) tRNA rhu {kkjdksa ds leqPp; }kjk fd;k tkrk gS vkSj ;s mRNA
ds dksMkWu dk iwjd gksrs gSaA

8. Hkkx 12-7 nsf[k,A

78