The accompanying illustration shows a portion of a gene undergoing transcription. The template and coding strands for the gene are labeled, and a segment of DNA sequence is given.

For this gene segment identify the direction in which the promoter [TIP 2] for this gene is located.

Verified step by step guidance

1. Examine the provided DNA sequence and identify the template strand and the coding strand. The template strand is the one used by RNA polymerase to synthesize the complementary RNA sequence, while the coding strand has the same sequence as the RNA (except thymine is replaced by uracil in RNA).
2. Determine the direction of transcription by identifying the 5' to 3' orientation of the RNA being synthesized. RNA polymerase synthesizes RNA in the 5' to 3' direction, which means it reads the template strand in the 3' to 5' direction.
3. Locate the promoter region, which is typically upstream (toward the 5' end) of the coding sequence on the coding strand. The promoter is the site where RNA polymerase binds to initiate transcription.
4. Analyze the diagram to identify any labels or markers indicating the promoter's position relative to the gene sequence. The promoter will be closer to the 5' end of the coding strand and the 3' end of the template strand.
5. Conclude the direction of the promoter based on its position relative to the transcription start site and the orientation of the strands. The promoter's location determines the direction of transcription and the strand that serves as the template.

Key Concepts

Gene Transcription

Gene transcription is the process by which a segment of DNA is copied into RNA by the enzyme RNA polymerase. This process involves the unwinding of the DNA double helix and the synthesis of a complementary RNA strand based on the template DNA strand. Understanding transcription is crucial for identifying the role of promoters and the directionality of gene expression.

Promoter Region

The promoter is a specific DNA sequence located upstream of a gene that serves as the binding site for RNA polymerase and transcription factors. It determines the direction of transcription and the start site for RNA synthesis. The orientation of the promoter indicates which strand of DNA will be used as the template for transcription, making it essential for understanding gene regulation.

DNA Strand Orientation

DNA strands have directionality, indicated by the 5' and 3' ends. The template strand is read in the 3' to 5' direction during transcription, resulting in RNA synthesis in the 5' to 3' direction. Recognizing the orientation of the DNA strands is vital for determining the location of the promoter and understanding how transcription proceeds.