Question

In a bacterium 'X' binary fission occurs at every 30 minutes. If its bacterial culture containing 10${}^{15}$ cells per ml is grown for 90 minutes, then what will be the total cell concentration per ml after 90 minutes?

• A. $8\times {10}^{15}$ cell
• B. $16\times {10}^{15}$ cell
• C. $32\times {10}^{15}$ cell
• D. $4\times {10}^{15}$ cell

Answer 1

The correct option is A $8\times {10}^{15}$ cell

During binary fission one cell divides to form two cells.For bacterium 'X' binary fission occurs at 30 minutes. So if the culture contains 10${}^{15}$ cells per ml then after 30 minutes the number of cells per ml will be 2 x ${10}^{15}$. After 90 minutes three sets of binary fission will occur in the bacterial culture and so the number of cells wil be 2${}^3$ x 10${}^{15}$ = 8 x 10${}^{15}$ cells per ml.

So, the correct answer is ' 8 x 10${}^{15}$ cells'.