The eukaryotic gene Gen-100 contains four introns labeled A to D. Imagine that Gen-100 has been isolated and its DNA has been denatured and mixed with polyadenylated mRNA from the gene.

Are intron regions single stranded or double stranded? Why?

Verified step by step guidance

1. <span>Step 1: Understand the structure of eukaryotic genes. Eukaryotic genes are composed of exons, which are coding regions, and introns, which are non-coding regions. During transcription, the entire gene, including both exons and introns, is transcribed into a precursor mRNA (pre-mRNA).</span>
2. <span>Step 2: Consider the process of RNA splicing. In eukaryotes, after transcription, the pre-mRNA undergoes splicing where introns are removed, and exons are joined together to form the mature mRNA. This mature mRNA is what is exported from the nucleus to the cytoplasm for translation.</span>
3. <span>Step 3: Analyze the denaturation and hybridization process. When the DNA of Gen-100 is denatured, it becomes single-stranded. If this denatured DNA is mixed with polyadenylated mRNA (which is mature mRNA), only the exonic regions of the DNA will hybridize with the mRNA, as introns are absent in the mature mRNA.</span>
4. <span>Step 4: Determine the state of introns. Since introns are not present in the mature mRNA, they will not have complementary sequences to hybridize with. Therefore, the intron regions of the denatured DNA will remain single-stranded.</span>
5. <span>Step 5: Conclude the reasoning. The intron regions are single-stranded because they do not have corresponding sequences in the mature mRNA to pair with, as they are removed during the splicing process.</span>

Key Concepts

Introns and Exons

Introns are non-coding regions of a gene that are transcribed into pre-mRNA but are removed during RNA splicing. Exons, on the other hand, are the coding sequences that remain in the mature mRNA. Understanding the distinction between these two is crucial for analyzing gene structure and function.

DNA Denaturation

DNA denaturation refers to the process of separating the two strands of the DNA double helix, typically through heat or chemical treatment. This process is essential for various molecular biology techniques, including the analysis of gene sequences and the study of mRNA, as it allows access to the single-stranded DNA template.

mRNA and Its Relationship to DNA

mRNA, or messenger RNA, is synthesized from DNA during transcription and serves as a template for protein synthesis. In the context of the question, the polyadenylated mRNA represents the processed form of the gene, which has had its introns removed, indicating that the intron regions are not present in the mature mRNA and are therefore not single-stranded in this context.