Question

If the sequence of bases in the coding strand of a double stranded $DNA$ is $5′\, GTTCGAGTC-3′$, the sequence of bases in its transcript will be

• A. $5′ - GACUCGAAC-3′$
• B. $5′ - CAAGCUCAG-3′$
• C. $5′ - GUUCGAGUC-3′$
• D. $5′ - CUGAGCUUG-3′$

Answer 1

Answer: (C)

During transcription, one of the two DNA strands functions as template strand and the other functions as coding strand. Template strand serves as template for transcription whereas coding strand does not take part in transcription. Hence, the mRNA produced has base sequence complementary to template strand while similar to coding strand except that thymine (T) is replaced by uracil (U). Here,
Coding strand $\to$ 5$'$ GTTCGAGTC 3$'$
Template strand $\to$ 5$'$ CAAGCTCAG $'$
Transcript $\to$ 5$'$ GUUCGAGUC 3$'$