Answer :
Final answer:
The correct option is a. 20 minutes. A single E. coli cell divides every 20 minutes under optimal conditions. After 20 minutes, one cell will become two. The answer to the question is (a) 20 minutes.
Explanation:
The correct option is a. 20 minutes. The question relates to the growth rate of E. coli bacteria under optimal conditions. Under these conditions, a single E. coli cell divides approximately every 20 minutes, leading to exponential or geometric growth.
This growth pattern means that after 20 minutes, one cell becomes two; after 40 minutes, those two cells become four; and so on. Since E. coli can double in such a short period, a 10L culture flask could rapidly become filled with bacteria starting from a single cell, especially considering that each new cell division cycle begins without any lag after a previous one has been completed.
Given this information, if we have a single E. coli cell in a flask, after 20 minutes, it would take the same 20 minutes for that single cell to divide into two cells under optimal conditions. Therefore, the correct answer to the student's question would be (a) 20 minutes.
