Question 16 of 25intermediate🔧 ApplyShort Answer2 marks

If the sequence of the coding strand in a transcription unit is written as follows: 5'-ATGCATGCATGCATGCATGCATGC-3' Write down the sequence of mRNA.

Correct Answer

5'-AUGCAUGCAUGCAUGCAUGCAUGC-3'

Exercise: EXERCISES | Q: 4 | (Chapter: 31)
For More Understanding

Explanation

According to the textbook context, the coding strand has the polarity 5′–3′ and has the sequence same as RNA, except that thymine (T) is present at the place of uracil (U). This strand does not act as a template for transcription but serves as the reference strand. Therefore, to obtain the mRNA sequence from the coding strand, we simply replace all thymine (T) bases with uracil (U) while keeping the same polarity (5′–3′). The template strand (with 3′–5′ polarity) is the one actually used by RNA polymerase to synthesize the complementary mRNA.

Solution Steps

  1. Step 1: Identify that the coding strand has the same sequence as RNA except T instead of U

  2. Step 2: Given coding strand: 5'-ATGCATGCATGCATGCATGCATGC-3'

  3. Step 3: Replace all T with U to get mRNA sequence: 5'-AUGCAUGCAUGCAUGCAUGCAUGC-3'

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