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. Understand the structure of eukaryotic genes: Eukaryotic genes contain exons (coding regions) and introns (non-coding regions). During transcription, the entire gene, including both exons and introns, is transcribed into pre-mRNA.
2. Learn about RNA splicing: In eukaryotes, introns are removed from the pre-mRNA during a process called splicing, leaving only the exons to form the mature mRNA. This mature mRNA is polyadenylated (has a poly-A tail) and is used for translation.
3. Consider the experimental setup: The DNA of the gene Gen-100 is denatured (separated into single strands) and mixed with the mature, polyadenylated mRNA. The mRNA will hybridize (base-pair) with its complementary sequence on the DNA strand.
4. Analyze the hybridization: Since the mature mRNA only contains exons, it will hybridize with the exon regions of the DNA. The intron regions, which are not present in the mRNA, will remain single-stranded because they have no complementary sequence in the mRNA to pair with.
5. Conclude the reasoning: The intron regions are single-stranded in this experiment because they are not represented in the mature mRNA and therefore cannot form double-stranded regions through hybridization.

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 introns and exons 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 results in single-stranded DNA, which is essential for processes like transcription and hybridization with mRNA. Recognizing the state of DNA during denaturation helps in understanding the context of intron and exon interactions.

mRNA and Its Structure

mRNA, or messenger RNA, is a single-stranded molecule that carries genetic information from DNA to the ribosome for protein synthesis. It is synthesized from the DNA template during transcription and includes only exons after splicing. Knowing the structure of mRNA is important for understanding how it relates to introns, which are absent in the final mRNA product.