Final answer:
The 7-methylguanosine cap and poly-A tail on eukaryotic mRNAs serve to facilitate mRNA export, enhance mRNA stability, initiate translation, protect mRNA from degradation, and help in ribosome binding. The correct option is (f).
Step-by-step explanation:
The 7-methylguanosine cap and poly-A tail are crucial modifications of eukaryotic mRNAs that play several roles in the mRNA lifecycle. Functions of both the cap and poly-A tail include facilitating mRNA export from the nucleus to the cytoplasm, enhancing mRNA stability by protecting it from degradation, and aiding in ribosome binding which initiates the translation process.
7-methylguanosine cap is added to the 5' end of the growing transcript and it serves to protect the mRNA from degradation while promoting the initiation of translation by ribosomes. The poly-A tail, a string of adenine nucleotides added to the 3' end, also protects mRNA from degradation and plays a role in the export to the cytoplasm, as well as having a regulatory role in mRNA stability during the translation process.
A comprehensive answer to the question "Which of the following are functions of both the 7-methyl guanosine cap and poly-A tail in eukaryotic mRNAs?" would include: facilitating mRNA export to the cytoplasm (a), enhancing mRNA stability (b), initiating translation (c), protecting mRNA from degradation (d), and aiding in ribosome binding (e). Thus, the correct answer would be: f. All of the above are correct.