Which of the following statements about eukaryotic mRNA is true?

• A. Eukaryotic mRNA typically contains a 5' cap and a poly(A) tail.
• B. Eukaryotic mRNA is double-stranded.
• C. Eukaryotic mRNA does not undergo splicing.
• D. Eukaryotic mRNA is synthesized in the cytoplasm.

Answer: (A)

Verified step by step guidance

1. Understand the structure of eukaryotic mRNA: Eukaryotic mRNA typically contains a 5' cap, which is a modified guanine nucleotide added to the beginning of the mRNA during transcription. This cap protects the mRNA from degradation and aids in ribosome binding during translation. Additionally, eukaryotic mRNA has a poly(A) tail, which is a sequence of adenine nucleotides added to the 3' end to stabilize the mRNA and facilitate its transport out of the nucleus.
2. Clarify the single-stranded nature of eukaryotic mRNA: Unlike DNA, eukaryotic mRNA is single-stranded, not double-stranded. This single-stranded structure allows it to be read by ribosomes during translation to synthesize proteins.
3. Explain the splicing process: Eukaryotic mRNA undergoes splicing, where introns (non-coding regions) are removed and exons (coding regions) are joined together. This process occurs in the nucleus before the mRNA is transported to the cytoplasm for translation.
4. Discuss the site of mRNA synthesis: Eukaryotic mRNA is synthesized in the nucleus during transcription. The enzyme RNA polymerase II transcribes the DNA template into pre-mRNA, which is then processed into mature mRNA before leaving the nucleus.
5. Evaluate the correct statement: Based on the above clarifications, the true statement is that eukaryotic mRNA typically contains a 5' cap and a poly(A) tail. The other options are incorrect because eukaryotic mRNA is single-stranded, undergoes splicing, and is synthesized in the nucleus, not the cytoplasm.