The synthesis of new DNA requires the prior existence of oligonucleotides to serve as primers. On Earth, these primers are small RNA molecules. This latter observation is evidence in support of the hypothesized existence of
A) a snowball Earth.
B) earlier genetic systems than those based on DNA.
C) the abiotic synthesis of organic monomers.
D) the delivery of organic matter to Earth by meteors and comets.
E) the endosymbiotic origin of mitochondria and chloroplasts.

Question

Quizplus · Accepted Answer

The fact that RNA molecules serve as primers suggests the existence of earlier genetic systems based on RNA, as RNA can both store genetic information and catalyze chemical reactions. This supports the hypothesis that RNA preceded DNA as the genetic material in early life forms.

The Synthesis of New DNA Requires the Prior Existence of Oligonucleotides