Two mRNAs (mRNA X and mRNA Y) are synthesized with the same exon sequences but poly-A tails of very different lengths. mRNA X is 7,500 bases long. mRNA Y is 6,900 bases long. The mRNA's are added to separate in vitro translation mixtures containing radioactive methionine and the reactions are allowed to proceed for 30 minutes. When the mixtures are analyzed which of the following outcomes will most likely occur?
A) The mRNA X mixture will contain radioactive proteins but the mRNA Y mixture will not.
B) The radioactive proteins in the mRNA X mixture will be larger in size than those in the mRNA Y mixture.
C) The mRNA X mixture will contain more radioactive proteins than the mRNA Y mixture.
D) The radioactive proteins in the mRNA X mixture will begin with methionine while those in the mRNA Y mixture will not.

Question

Quizplus · Accepted Answer

The length of the poly-A tail can influence mRNA stability and translation efficiency. A longer poly-A tail, as in mRNA X, typically leads to more efficient translation and thus more protein production, which in this case would be detected as more radioactive proteins due to the incorporation of radioactive methionine.

Two MRNAs (MRNA X and MRNA Y) Are Synthesized with the Same