Question

If the sequence of nitrogen bases of the coding strand of DNA in a transcription unit is: 5' -ATGAATG-3', the sequence of bases in its RNA transcript would be;

• A. 5' - AUGAAUG - 3'.
• B. 5'- UACUUAC - 3'
• C. 5'- CAUUCAU - 3'
• D. 5'- GUAAGUA - 3'

Answer 1

The correct option is A 5' - AUGAAUG - 3'.

Coding and non coding strand of DNA :

The DNA strand with the polarity in $5^{\prime }\to 3^{\prime }$ is called a coding strand. The sequence of the RNA transcript is the same as the sequence of the coding strand of DNA except thymine in DNA is replaced by uracil in RNA.

The DNA strand with the polarity in $3^{\prime }\to 5^{\prime }$ is called a non coding strand or template strand, as the DNA dependent RNA polymerase synthesises RNA using this strand as template.



Sequence of RNA transcript:

If the sequence of the coding strand is 5' - ATGAATG - 3'. Then the sequence of the RNA transcript will be 5’- AUGAAUG - 3’.

Hence option a, 5' - AUGAAUG - 3’ is the correct answer.


Final answer: a. 5' - AUGAAUG - 3