How many bacteria would it take to cover the entire digestive tract?
1 Answer
Feb 10, 2015
It would take 3 × 10¹³ bacteria to cover the entire digestive tract.
Explanation:
I will make some assumptions:
- The bacteria are all the same size as E. coli.
- A typical bacterium is 2 µm long and 0.5 µm wide.
- The mucosal surface of the digestive tract interior averages ∼32 m² (of which about 2 m² is the large intestine).
The last two estimates come from the National Center for Biotechnology Information.
Step 1. Calculate the area of a bacterium.
Convert this area to square metres.
Step 2. Calculate the number of bacteria required.
The area of the digestive tract is 32 m² (about half the area of a badminton court).
That's 30 trillion bacteria!