NEETZoologyMolecular Basis of Inheritance
An mRNA molecule has the following nucleotide sequence: 5' - U A C G G A U C - 3' What will be the sequence and polarity of the template DNA strand from which it was transcribed?
Options
- A5' - T A C G G A T C - 3'
- B5' - A T G C C T A G - 3'
- C3' - A T G C C T A G - 5'
- D3' - A U G C C U A G - 5'
Correct answer
C. 3' - A T G C C T A G - 5'
Step-by-step solution
The template DNA strand is complementary and antiparallel to the mRNA sequence. Given mRNA: 5' - U A C G G A U C - 3' By applying complementary base pairing rules (U pairs with A, A pairs with T, C pairs with G, G pairs with C) and reversing the polarity, the template DNA strand is: 3' - A T G C C T A G - 5' The sequence 5' - T A C G G A T C - 3' represents the coding strand, not the template strand. The sequence 5' - A T G C C T A G - 3' has the wrong polarity, and DNA does not contain uracil (U). Answer: 3' - A T