_____________________________ 239. DNK molekulasining ma'lum qismida 1380 ta vodorod
bog’lari bo’lib, undagi sitozinli nukleotidlar 90 juftni tashkil etadi.
Shu DNK bo‘lagi asosida transkripsiya jarayonida hosil bo’lgan i-
RNK molekulasidagi nukleotidlar sonini aniqlang.
A) 700 B) 645 C) 1200 D) 600 Ishlanishi: 1) 2A+3G=H => S=G => 2A+3*180=1380
2A=1380-540 2A=840 A=420
2) A+G=N => 180+420=600N DNK ni 1 ta ipi yoki i-RNK
dagi N lar Javob: D _____________________________ 240. Oqsil zanjirining molekulyar massasi 12000. Bitta
aminokislotaning o‘rtacha massasi 120 ga teng. Qo‘shni nukleotidlar
orasidagi masofa 0,34 nm bo’lsa, quyidagilarni aniqlang.
a) genning uzunligi (nm); b) DNK qo‘sh zanjiridagi nukleotidlar
soni; c) i-RNKdagi nukleotidlar soni; d) purin va pirimidin
asoslarining o‘zaro nisbati;
1) 102; 2) 34; 3) 4000; 4) 600; 5) 100; 6) 300; 7) 120; 8) 1:1; 9)
1:3; 10) 1:2
A) a-1; b-4; c-7; d-10 B) a-1; b-4; c-6; d-8 C) a-3; b-7; c-4; d-10 D) a-2; b-5; c-6; d-9
Ishlanishi: 1) 12000/120=100AK; 100*3=300N
a) L=300*0,34=102nm; b) 300*2=600N;
c) i-RNK da-300N; d) 1:1 Javob: B _____________________________ 241. DNK molekulasida adenin va timin nukleotidlari orasida
ikkita, guanin va sitozin nukleotidlari orasida uchta vodorod bog’i
borligi ma’lum. DNK fragmentida 1040 ta vodorod bog’i bo’lib,
ushbu fragmentda adenin nukleotidlari umumiy nukleotidlarning
20% ini tashkil etsa, ushbu molekuladagi jami nukleotidlar sonini
aniqlang.
A) 810 B) 800 C) 1000 D) 832 Ishlanishi: 1) A-20%=20%-T 40%-A+T 100-40=60%
60:2=30%-G-S
2) 30/20=1,5 G=1,5A
3) 2A+3G=H => 2A+3*1,5A=1040
2A+4,5A=1040 6,5A=1040 A=160
4) 2*160+3G=1040
3G=1040-320 3G=720 G=240
5) (A+G)*2=(160+240)*2=400*2=800N Javob: B
