nucleotit hay mach m A R N do gen phien ma c6 1497 ribonucleotit. So Ian sao ma (phien ma) tir gen dot bien la: 7485 : 1497 = 5 Ian.
B a i 5: Gen A quy dinh mau mat do lam mat 3 cap nucleotit va tao thanh alen a
hoac a|. ^^^./•=v^,:•*.;^..^^^.;v
1. Gia thie't alen a difdc tao thanh bang mot trong 3 con diTcJng sau day thi phan tuT protein tu'dng iJng se khdc vdi so protein do gen A tdng hdp nhtf the nao? phan tuT protein tu'dng iJng se khdc vdi so protein do gen A tdng hdp nhtf the nao?
Ca'm nang tg 6n va luy$n thi Sinh hgc - Phung Duy Dfl'ng
Cho rang trong triTdng hdp nay moi axit amin chi do mot bp ba xac dinh, va dot bien khong lien quan den codon ket thiic.
a) Ba cap nucleotit bi mat chiJa trpn trong mot bp ba ma hoa.
b) Hai nucleotit thupc mpt bp ba ma hoa, con mot nucleotit ke tiep thupc bp ba ke'tiep. ba ke'tiep.
c) Hau qua cua dot bien d a va b c6 giong nhau hay khong? Tai sao?
2. Gia thiet alen ai tao thanh do dot bien mat ba nucleotit d cac vi tri khac nhau cua gen A thi phan tuT protein do gen bi dot bien tong hdp khac vdi protein nhau cua gen A thi phan tuT protein do gen bi dot bien tong hdp khac vdi protein do gen A tong hdp nhu" the nap?
Cho biel phan tuf protein do gen A tdng hdp c6 198 axit amin va cac axit amin tu'dng i^ng vdi cac vi tri bi bien ddi trong gen chi do mpt bp ba ma hoa quy dinh.
a) Mat cap nucleotit so 4, so 7 va so 12. b) Mat cap nucleotit so 591, so 594 va so 597. b) Mat cap nucleotit so 591, so 594 va so 597.
HUdngddn
,,, 1. Sir khac nhau giffa phan tuT protein do gen A va do alen a tdng hdp. a) protein dot bien khac protein binh thiTdng 1 axit amin.
b) protein dpi bien kem protein binh thrfdng 1 axit amin va c6 mpt axit amin bi thay the. bi thay the.
j; c) Khong. V i 2 codon diTdc hinh thanh sau dpt bien cua hai trrfdng hdp la khac nhau. a a) Tru'dng hdp 3 cap nucleotit bi mat nam 5 3 vi tri khac nhau:
Vi tri so 4 thupc codon thu" 2, vi tri so" 7 thupc cpdpn thu' 3, vj tri so 12 thupc codon thi? 4.
Tru-dng hdp nay, phan tuT protein do alen ai tdng hdp kem phan tu" protein do gen A tdng hdp mpt axit amin va c6 2 axit amin d dau chuoi polipeptit khac
vdi 2 axit amin tu'dng vtng ciia chuoi polipeptit do gen A tdng hdp.
b) Tru-tJng hdp 3 cap nucleotit bj mat nam d cac vi tri 591, 594 va 597: Chuoi polipeptit do gen a i tdng hdp it hdn chuoi polipeptit do gen A tdng Chuoi polipeptit do gen a i tdng hdp it hdn chuoi polipeptit do gen A tdng hdp mpt axit amin v a c6 2 axit amin d cudi chuoi khac vdi 2 axit amin tiTdng iJng tren chudi polipeptit do gen A tdng hdp.
Bai 6: Gen A chi huy tdng hdp phan tu" protein gdm 198 axit amin.
1. Dot bien gen lam them 1 cap nucleotit d giiJa cap sd'6 va cap so 7 thi phan
i\i protein do gen dot bien tdng hdp khac vdi phan tuT protein do gen A tdng hdp nhq thenao?
2. Dpt bien lam them 1 cap nucleptit d khoang gii?a cap 594 va 595 thi phan tur protein do gen dot bien tdng hdp khac vdi phan tuT protein do gen A tdng hdp tur protein do gen dot bien tdng hdp khac vdi phan tuT protein do gen A tdng hdp nhU'the'nao?
Gia thiet r^ng dot bien khong anh hiTdng den chtfc n^ng cua codon ke't thuc cua gen.
122
Cty TNHH MTV DWH Khang Vigt
HUdng ddn *'
1. Them 1 cap nucleotit 6 giffa cap so 6 va so 7 se lam thay ddi cac bp ba ma 6a tir codon thuT 3 trd di. Vay protein do gen dot bien tdng hdp chi c6 axit amin 6a tir codon thuT 3 trd di. Vay protein do gen dot bien tdng hdp chi c6 axit amin
1? nhait gidng vdi axit amin tiTdng ufng tren phan tuT protein do gen A tdng hdp. 2. Them mpt cap nucleotit d giiJa cap so 594 va 595 thi se lam thay ddi codon thuf 2 ke tur codon ket thuc. i"-
Vi vay protein do gen dot bien tdng hdp c6 mpt axit amin cud'i cung khdc vdi axit amin tu'dng iJng cua protein do gen A tdng hdp.
Bai 7: Mpt gen chi huy tdng hdp chudi polipeptit gdm 198 axit amin, c6 ti le X = 0,6 . Mpt dot bien xay ra tuy khong lam thay ddi so' lu'dng nucleotit cua X
en nhvfng da lam thay ddi ti le ndi tren.
\. Khi ti le — trong gen dot bien = 60,43% hay cho biet: _ + Dot bien thupc dang nao?
+ So lien ket hidro trong gen dpt bien thay ddi nhtf the nao?
+ Chuoi polipeptit cua gen dpt bien khac vdi chupi polipeptit cua gen binh .tfdng nhu" the nao?
2. Khi ti le —=59,57%, hay cho biet: t + Cau triic cua gen da thay ddi nhiT the nao? ' " > ' * ';«''>^ + Cau triic cua gen da thay ddi nhiT the nao? ' " > ' * ';«''>^
+ So' lien ket hidro trong gen thay ddi nhiT the' nao? >• • •
Hitdngddn '
1. Chuoi polipeptit cua gen do c6 198 axit amin, chiJng to mach mang ma B'ccp 198 + 2 = 200bpba B'ccp 198 + 2 = 200bpba
SP nucleotit ciia gen (N) la: 200 x 3 x 2 = 1200 nucleotit , | Ap dung cong thufc: T + X = - N . Khi T = 0,6X. «'
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It'
' n M 'H.I i\
Ta c6: 0,6X + X = ^ N = 600=>X = 375; T = 225.
T
Trong gen dpt bien c6: —=60,43% .
T T Ti 16 — cua gen binh thiTdng la — = 0,6. Ti 16 — cua gen binh thiTdng la — = 0,6.
X X
' Nhir vay ti le — tang chiJng to c6 sir thay the cap G - X b^ng cap A - T. X
Goi X la SP cap nucleptit bi thay the, ta ce phtfdng trinh: ' ' " • '
T-.X 225 + x ^ ^ ^ j X + x 375-x
Ca'm nang tir 6n va luy^n thi Sinh hoc - Phung Duy Pgng
+ V a y dot b i e n thuoc dang thay the' 1 cap G - X bkng cap A - T . + So l i e n k e t h i d r o s e b i thay d o i nhiTsau: . ;
Gen dot b i e n k e m gen binh thi/cfng 1 l i e n ke't hidro.
+ C h u o i polipeptit cua gen dot bien c6 the khac chuoi polipeptit cua gen b m h thu'dng ve thanh phan 1 axit amin hoac dot bien khong l a m thay d o i chuoi polipeptit tijy theo codon trufdc dot bien va codon sau dot b i e n ma hoa 2 axit a m i n khac nhau hay cung ma hoa 1 axit amin. v * ;
T T
2. T i le — = 5 9 , 5 7 % . So v d i t i le — = 0,6 (cua gen b i n h thi/cJng) la giam, X X X X
chiJng to CO sirthay the cap A - T b a n g cap G - X . ; G o i X la so' cap nucleotit bj thay the'.