Because prokaryotic genes have no introns the mRNA can be translated while it is still being synthesized, i.e., in prokaryotes transcription and translation are coupled. Nomarski optics is a microscope system that can be used for localizing intracellular proteins by immunocytochemistry. The first base of the codon can vary without changing the amino acid the codon stands for. When a mutation introduces a STOP codon in the middle of an open reading frame premature chain termination occurs. Some bases are modified.
Hydrogen bonds form which stabilize the structure.
An amino acid is attached to the acceptor arm. Introns are found in eukaryotes. Prokaryotes have a single, circular chromosome whereas eukaryotes have multiple chromosomes. In eukaryotes, the genes coding for sets of enzymes involved in the same metabolic task are often arranged in operons. In bacteria, the genes coding for sets of enzymes involved in the same metabolic task are often arranged in operons and transcribed into polycistronic mRNAs.