What are the two types that snoRNAs generally exist in? And what are the two key functions of snoRNAs?
a) Guide snoRNAs, Antisense snoRNAs; Catalysis, Translation
b) Box C/D snoRNAs, Box H/ACA snoRNAs; Methylation, Pseudouridylation
c) Small snoRNAs, Large snoRNAs; Replication, Transcription
d) Prokaryotic snoRNAs, Eukaryotic snoRNAs; Splicing, Ribosome assembly