iD magazine



There’s a lot of focus right now on microorgan­isms, so it was timely to feature a story in the November issue on bacteria and how they are dealt with. It is especially important to highlight the dangers of the overuse of antibiotic­s, which can lead to “superbugs” and result in a shortage of drugs to effectivel­y combat diseases. One thing I wondered about was the circular chromosome in the bacterium diagram—it doesn’t look circular? James Degarmo, Coral Springs, FL

There are two kinds of bacterial DNA: One occurs in the form of plasmids, small extrachrom­osomal circular DNA strands in the cytoplasm that can replicate independen­tly of the main chromosome and that are clearly round, and the other is the main DNA strand of the chromosome. Although the main strand doesn’t appear to be circular in the diagram, circular in this case just means a closed loop—no free ends, not linear— and due to the strand’s length it can still have folds and bends.

Newspapers in English

Newspapers from United States