A bacterium divides every 35 minutes. If a culture containing 105 cells per mL is grown for 175 minutes, what will be the cell concentration per mL after this time?
Correct answer: C. 32 x 10^5 cells
- A. 5 x 10^5 cells
- B. 35 x 10^5 cells
- C. 32 x 10^5 cells
- D. 174 x 10^5 cells
Explanation
The bacteria divide every 35 minutes. Over 175 minutes, the bacteria will divide 5 times (175 / 35 = 5). Each division doubles the number of bacteria, so after 5 divisions, the number of bacteria is 25 = 32 times the initial count. Starting with 105 cells per mL, the concentration becomes 32 x 105 cells per mL.Other options do not correctly calculate the number of divisions or misunderstand the relationship between time and cell doubling.
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