How long in centimeters or inches is the DNA of E. coli?

Question

I've been told that E. coli's circular chromosome has 4.6 million base pairs. If the entire chromosome were expanded, as when a cell is lysed, and all kinks and twists were removed, how long would it be in centimeters or inches?

Answer 1

OK. DNA has 10 bases for each turn of the double helix, and each turn take 3.4 nanometers. So, if you do the math, you'll find that the E. coli chromosome is about 1.6 millimeters long.

That may not sound like so much, but it is about 750 times longer than the E. coli cell.