Explain (in one or two lines) the function of the following:
$(a)$ Promoter
$(b)$ $tRNA$
$(c)$ Exons

$A$: Sigma factor of $RNA$ polymerase recognizes the start signal region in prokaryotes.
$R$: Promoter region lies at $5'$ end of the coding strand, not the template strand.

Which one of the following processes is exclusively concerned with transcription?

$A$ $DNA$ strand with the sequence $AACGTAACG$ is transcribed. What is the sequence of the $mRNA$ molecule synthesized?

What do the processes $1$ and $2$ represent in the following sequence?
$TAC \, AAG \, GCG \, AUA \, CGA$
$\downarrow (1)$
$AUG \, UUC \, CGC \, UAU \, GCU$
$\downarrow (2)$
$Met - Phe - Arg - Tyr - Ala$

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: