Refer to the figure below showing an RNA oligonucleotide undergoing hydrolytic breakdown into its component nucleotides. Hydrolysis occurs in DNA molecules, too, but at a rate that is 100 times slower than that in RNA.Which statement explains how this information supports the hypothesis that RNA and not DNA became the first complex molecule that assisted in the synthesis of proteins during the rise of life on Earth?
A) DNA is more stable than RNA, which means that DNA molecules would have resisted evolutionary change during the rise of life on primitive Earth.
B) RNA contains a different set of bases than DNA, and that difference likely affected the ability of RNA to assist in the polymerization of amino acids into peptides.
C) DNA is protected within the nucleus of a cell, whereas RNA is available in the cytoplasm of a cell, where it can react with other molecules more readily.
D) RNA contains a reactive hydroxyl group that is absent in DNA and that can catalyze chemical change in itself or in other molecules.
E) DNA tends to remain as one long strand rather than breaking up into smaller fragments as RNA does, which makes RNA more mobile as a catalyst.

Question

Refer to the figure below showing an RNA oligonucleotide undergoing hydrolytic breakdown into its component nucleotides.  Hydrolysis occurs in DNA molecules, too, but at a rate that is 100 times slower than that in RNA.Which statement explains how this information supports the hypothesis that RNA and not DNA became the first complex molecule that assisted in the synthesis of proteins during the rise of life on Earth?
A) DNA is more stable than RNA, which means that DNA molecules would have resisted evolutionary change during the rise of life on primitive Earth. 
B) RNA contains a different set of bases than DNA, and that difference likely affected the ability of RNA to assist in the polymerization of amino acids into peptides. 
C) DNA is protected within the nucleus of a cell, whereas RNA is available in the cytoplasm of a cell, where it can react with other molecules more readily. 
D) RNA contains a reactive hydroxyl group that is absent in DNA and that can catalyze chemical change in itself or in other molecules. 
E) DNA tends to remain as one long strand rather than breaking up into smaller fragments as RNA does, which makes RNA more mobile as a catalyst.

Quizplus · Accepted Answer

The fact that RNA undergoes hydrolysis at a faster rate than DNA supports the hypothesis that RNA, with its unique properties such as the reactive hydroxyl group, played a role in the synthesis of proteins during the rise of life on Earth. DNA's stability and protection within the nucleus do not necessarily explain why RNA, rather than DNA, was the first complex molecule to assist in protein synthesis. The differences in base pairs between RNA and DNA are not directly related to their ability to assist in polymerization of amino acids. The idea that RNA is more mobile than DNA is not sufficient to explain why RNA, rather than DNA, was the first complex molecule to assist in protein synthesis.

Refer to the Figure Below Showing an RNA Oligonucleotide Undergoing