Question

What is the perimeter length of E. coli DNA?

Options

• Approximately 350 µm

• Approximately 1.1–1.36 mm (1100 µm)

• Approximately 2.2 metres

• Approximately 2 µm

Answer 1

E. coli DNA has a perimeter length of approximately 1.1–1.36 mm (1100 micrometres) and contains about 4.6 million base pairs. Since the E. coli cell itself is only 2–3 micrometres in length, the DNA must be compacted approximately 400–700 times to fit within the bacterial cell.