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

(a) Promoter
Promoter is a region of DNA that helps in initiating the process of transcription. It serves as the binding site for RNA polymerase.
(b) tRNA
tRNA or transfer RNA is a small RNA that reads the genetic code present on mRNA. It carries specific amino acid to mRNA on ribosome during translation of proteins.
(c) Exons
Exons are coding sequences of DNA in eukaryotes that transcribe for proteins.

(a) Promoter :

It is a gene that lies near operator which functions as binding site structural genes if operator allows.

(b) tRNA :
Functions as adapter molecule that picks  up a particular amino – acid from cellular pool and takes same over A site, m – RNA for incorporation into polypeptide.

(c) Exons :
Coding segments present in primary transcript which on splicing by snRNP’s get joined to form functional m-RNA.