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. Scanning electron microscope. Fluorescence activated cell sorter Cells and tissues frequently have to be fixed for viewing in the microscope. In the picture below a moving DNA replication fork is shown.