The Surfaces of the Two Ribosomal Subunits That Face One

Multiple Choice

The surfaces of the two ribosomal subunits that face one another contain the binding sites for the mRNA and incoming tRNAs and are thus of key importance for the function of the ribosomes.The fact that these surfaces consist largely of RNA supports what proposal?

A) the proposal that primordial ribosomes were composed solely of proteins
B) the proposal that primordial ribosomes were composed exclusively of RNA
C) the proposal that primordial ribosomes were composed exclusively of DNA
D) the proposal that prokaryotes gave rise to eukaryotes
E) the proposal that endosymbiosis gave rise to eukaryotes