Related words. 1  post verb. 2  post up phrasal verb. 3  post off phrasal verb.  cross-post 1  verb. 1. a public notice, especially one advertising a job Synonyms and related words. Types of advertisement:ad, advert, advertisement...  2. a job that someone is sent somewhere to do, usually in another country Synonyms and related words.
Catalytic RNAs, or ribozymes, are a fossil record of the ancient molecular evolution of life on Earth and still provide the essential core of macromolecule synthesis in all life forms today.
The main difference between ribozymes and enzymes is that RNA catalysts are composed of nucleotides, whereas enzymes are composed of amino acids. Ribozymes also perform a more limited set of reactions, although their reaction mechanisms and kinetics can be analysed and classified by the same methods.