<prompt> Nonsense or genetic codons are what in number?2345  <response>: Ans. b 3. Ref. Harper Biochemistry, 25th ed., 453.START AND STOP CODONS1AUG or rarely GUG is the mRNA initiation codonKey:--AUG inaugurates protein synthesis.2AUG codes for methionine, which may be removed before translation is completed.3Stopnon-sensegenetic codons: UGA, UAA, UAG.Key:--UGA-U go Away, UAA--U Are Away, UAG--U Are Gone4There are 4364 possible codon sequences because mRNA is composed of 4 bases and each codon is made up of 3 bases.5Cycloheximide acts by inhibiting protein synthesis in eukaryotes by binding to 60s ribosomal sub-unit and inhibiting peptidyl transferase. 