Common RNA species molecular sizes:

Nucleotides Moleuclar Wieght(daltons)
E. coli
tRNA 75 2.6 x 10^4
5S rRNA 120 4.1 x 10^4
16S rRNA 1541 5.2 x 10^5
23S rRNA 120 9.9 x 10^5
Mouse
18S rRNA 1869 6.4 x 10^5
28S rRNA 4712 1.6 x 10^6
Human
18S rRNA 1868 6.4 x 10^5
28S rRNA 5025 1.7 x 10^6


While you are here :-), introducing:
Conveniently Extract RNA!

Extract plasmids for quick PCR or sequencing screening.

Over 700bp CE sequencing readout directly from an overnight culture of a 14kb low copy plasmid