A Level Biology Practice Exam

Which strand of DNA contains the genetic code for a protein?

1. Template strand

2. Anti-sense strand

3. Sense strand

4. Complementary strand

The correct answer is: Sense strand

The sense strand of DNA carries the genetic code for proteins because it has the same sequence as the mRNA that is produced during transcription, with the exception of uracil replacing thymine. This strand is also referred to as the coding strand, as it contains the codons that will be interpreted by the ribosomes to assemble the corresponding amino acids. The information encoded in the sense strand is translated into a protein, making it essential for the expression of genetic traits. The other options refer to strands that are not directly involved in coding for proteins. The template strand is used by RNA polymerase to synthesize mRNA, while the anti-sense strand is another name often used for the template strand. The complementary strand serves as a pairing partner to the sense strand but does not contain the coding information necessary for protein synthesis.