An intron is a sequence of ____ RNA that is ____ a primary transcript, while an exon is a sequence of ______ RNA that is ______ a primary transcript.
a. non-coding ... cut out of ... coding ... left in
b. transfer ... cut out of ... non-coding ... left in
c. coding ... left in ... non-coding ... cut out of
d. transfer ... left in ... transfer ... cut out of
e. non-coding ... left in ... coding ... left in
Adv.
The result of transcription will be an immature mRNA molecule, which is called as primary transcript. The primary transcript will undergo modifications to become into a mature mRNA molecule. The primary transcript will contain non-coding sequences and coding sequences. The non-coding sequences are called introns and they are removed during modification. The coding sequences are called exons and joined together to form a mature m RNA molecule.
Hence, the correct option is (a) non-coding…cut out of…coding…left in.