Subject Experts Solutions for Exercise 3: NCERT EXEMPLAR PROBLEMS

In some viruses, DNA is synthesized by using RNA as template. Such a DNA is called

If Meselson and Stahl's experiment is continued for four generations in bacteria, the ratio of ${}^{15}\mathrm{N}/{}^{15}\mathrm{N} :{ }^{15}\mathrm{N}{/}^{14}\mathrm{N} :{ }^{14}\mathrm{N}{/}^{14}\mathrm{N}$ containing DNA in the fourth generation would be

If the sequence of nitrogen bases of the coding strand of DNA in a transcription unit is: $5^{\text{'}}-\mathrm{ATGAATG}-3^{\text{'}},$ the sequence of bases in its RNA transcript would be

The RNA polymerase holoenzyme transcribes

If the base sequence of a codon in $\mathrm{mRNA}$ is $5^{\text{'}}-\mathrm{AUG}-3^{\text{'}},$ the sequence of $\mathrm{tRNA}$ pairing with it must be

The amino acid attaches to the $\mathrm{tRNA}$ at its

To initiate translation, the $\mathrm{mRNA}$ first binds to

In E. coli the lac operon gets switched on when