Abituriyentlarga qulayliklari

J:189


10. DNK fragmentida 1100 ta nukleotid bo'lib, T+G+S yeg'indisi T+G+A yeg'indisidan, 1,2 martta katta bo'lsa, fragment tarkibidagi jami vodarod bog'lar sonini toping.
A) 1550 B) 1450 C) 1540 D) 1350
Yechimi:
1) 2x+2y=1100
x+2y
-------------------=1,2
2x+y
x=200 A va T
y=350 G va S
2) 200 × 2=400
3) 350 x 3=1050
4) 1050+400=1450
Javob: 1450 B

11. Ikki xil DNK bo’lagidan sentezlangan oqsillar tarkibidagi pepted bog’lari soni yig’indisi 43ta.DNK nukleotedlari orasidagi vodorod bog’lar yig’indisi 330ta.Katta DNK bo’lagida Adinin jami nukleotedlar sonining 20%ini tashkil etsa,kichik DNK da Guanin jami nukleotedlarning 12.5% qismini tashkil etadi. Ikkala DNKdagi vodorod bog’lar sonini farqini toping.

A)40 B)50 C)60 D)70
YECHIMI:
43+2 = 45. 45x3 = 135
135x2 = 270(ikkala DNK nukl)

1-DNK. 2-DNK

A=37,5% A=20%
T=37,5% T=20%
S=12,5% S=30%
G=12,5% G=30%

0,375x2 = 0,75. \

1,125
0,125x3 = 0,375/

0,2x2 = 0,4 \

1,3
0,3x3 = 0,9/

x + y = 270 |1,3

1,3x+1,125=330
0,175y = 21
y = 120
x = 150

120x0,375 = 45

120x0,125 = 15

45x2 = 90(H bog')

15x3 = 45(H bog')
90+45 = 135(jami H bog')

150x0,2 = 30

150x0,3 = 45

30x2 = 60(H bog')

45x3 = 135(H bog')
60+135 = 195(jami H bog')
195 - 135 = 60
Javob: 60. (C)

12. Bir molikula oqsil sinteziga javobgar bo'lgan DNK fragmentidagi guanin va sitozin nukleotidlari orasidagi vodarod bog'lar soni bilan, adinin va timin o'rtasidagi vodarod bog'lari soni yeg'indisi 750 ga, ayirmasi esa, 150 ga teng bo'lsa, DNK fragmentidagi jami nukleotidlar sonini aniqlang.

A) 450 B) 600 D) 650 D) 500
Yechimi:
1) x + y=750
x - y=150
X=450 G va S
Y=300 A va T
2) 450:3=150 G va S bitta zanjirda
3) 300:2=150 ta A va T bitta zanjirda
4) 150 × 2=300 ta G va S
5) 150 × 2=300 ta A va T
6) 300 + 300=600 ta jami nukleotid
Javob: B

13. (A+T)-(G-S)=16 va umumiy vodorod boglar soni 666 bolsa, DNK fragmenti uzunligini aniqlang.(qo`shni nukleotidlar orasidagi masofa 0,34nm)

A) 91,12 B) 50,4 C) 61,2 D) 45