Question

A host cell has intracellular bacterial symbionts. If the growth rate of the bacterial symbiont is always 10% higher than that of the host cell, after 10 generations of the host cell the density of bacteria in host cells will increase

• A. 10%
• B. Two-fold
• C. Ten-fold
• D. Hundred-fold

Answer 1

Answer: (D)

Hundred-fold

According to the question, the bacterial growth rate is 10% higher than the host; as we know that there is exponential increase in cell number by cell division, this is due to the fact the one cell produces two daughter cells and each of which then serve as parent cell and produces four daughter cells in total. The growth rate of symbiont is 10% higher thus after 10 generations, its cell density will be 10${}^{10}$=100 times higher than that of the host cell. Correct answer is D.