Question

The template strand of a gene contains the sequence 3’-TTCAGTCGT-5’. Imagine that the non-template plate sequence was transcribed instead of the template sequence. Draw the mRNA sequence and translate it using Figure 17.6. (Be sure to pay attention to the 5’ and 3’ ends.) Predict how well the protein synthesized from the non-template strands would function, if at all.

Short answer

The protein is produced from the template strand. If the mRNA sequence is transcribed from a non-template strand, then the protein formed is non-functional.

Step-by-step solution

Description of template strand and non-template strand

The DNA strand that serves as the template for the process of transcription is the template strand. It runs in the direction of 3’ to 5’ direction.

The DNA strand that is identical to the RNA strand is the non-template strand. It is also known as the coding strand.

The template strand is provided in the given case as 3'-TTCAGTCGT-5. The non-template strand is complementary to the template, and the sequences of the non-template strand are 3’ACGACTGAA 5’.

Definition of protein synthesis

Protein synthesis is the process that produces protein from mRNA, which is known as translation. It takes place in the ribosome, which is the site of protein production.

Protein produced from the non-template strand

The non-template strand (3’ACGACTGAA 5’) is transcribed into mRNA with the sequence as 5’ UGCUGACUU 3’. In this mRNA, there is a three-letter codon as UGA, which is a stop codon. It can terminate the translation process.

The translation of this mRNA will result in termination of the translation process in-between, resulting in the formation of non-functional protein.

Hence, protein translation from a non-template strand forms a non-functional protein due to a stop codon.