$A$ geneticist isolates a gene for a specific trait under study; she also isolates the corresponding $mRNA$. Upon comparison,the $mRNA$ is found to contain $1,000$ fewer bases than the $DNA$ sequence. Did the geneticist isolate the wrong $DNA$?

Do you think that the alternate splicing of exons may enable a structural gene to code for several isoproteins from one and the same gene? If yes,how? If not,why so?

$RNA$ polymerase $II$ transcribes which type of $RNA$?

If the sequence of bases on the coding strand of $DNA$ is $AAGCCTATCAG$,what will be the sequence of bases on the $mRNA$?

Which enzyme plays an important role in transcription?

Which of the following statements are correct with reference to a transcription unit?
$A$. $A$ transcription unit in $DNA$ is defined primarily by three regions: promoter, structural gene and terminator.
$B$. The promoter is said to be located towards the $5'$-end of the structural gene.
$C$. The promoter is a $DNA$ sequence that provides binding site for $RNA$ polymerase.
$D$. The promoter defines the template and coding strands.
$E$. The terminator is located towards the $3'$-end of the coding strand and it defines the end of the process of transcription.
Choose the correct answer from the options given below: