All of the following statements about Ribozymes are false, EXCEPT:
Ribozymes are RNAs which exhibit highly substrate specific catalytic activity. They play a key role in the intron transcripts excision and exon transcripts splicing events essential for the conversion of pre mRNA to mature mRNA. Ribozymes catalyzed transesterification, and ultimate hydrolysis of phosphodiester bonds in RNA molecules. Ref: Textbook Of Medical Biochemistry (3Rd Edn.) By S. Ramakrishnan page 338.
They are DNA molecules
They are not present in ribosomes
They plays a key role in RNA synthesis
They play a key role in post-transcriptional conversion of pre-mRNA to mature mRNA