The DNA sequence below gives the first 12 base pairs of the transcribed region of a gene, and the template and nontemplate strands of DNA are identified. The transcription start is the thymine nucleotide at the end of the sequence given. Use the diagram to answer the list of questions. Make a copy of the diagram before you begin answering the questions, or have one group member diagram the answers for bacteria and another group member diagram the answers for eukaryotes.

Nontemplate strand  ___________TTGCTACGGTCA___________
Template strand        ___________AACGATGCCAGT___________

Write the anticipated eukaryotic consensus sequence(s) in the approximate position(s) on the diagram.

Key Concepts

Transcription

Transcription is the process by which the genetic information encoded in DNA is copied into messenger RNA (mRNA). This occurs in the nucleus of eukaryotic cells, where RNA polymerase binds to the template strand of DNA and synthesizes a complementary RNA strand. Understanding transcription is crucial for analyzing gene expression and the role of various sequences in regulating this process.

Consensus Sequence

A consensus sequence is a sequence of DNA that represents the most common nucleotides found at each position in a set of similar sequences. In the context of transcription, consensus sequences are often found in promoter regions and are critical for the binding of transcription factors and RNA polymerase. Identifying these sequences helps in understanding how genes are regulated in both prokaryotes and eukaryotes.

Eukaryotic Gene Structure

Eukaryotic genes typically consist of exons (coding regions) and introns (non-coding regions), with transcription occurring in the nucleus. The presence of a promoter region, which includes consensus sequences, is essential for initiating transcription. Additionally, eukaryotic mRNA undergoes processing, including capping and polyadenylation, before being translated into proteins, making the understanding of gene structure vital for analyzing gene function.