Question

A bacterium divides every $35$ minute. If a culture containing ${10^5}$ cells/ml is $175$ minutes. What will be the cell concentration after that period:
(A). $175 \times {10^5}$
(B). $35 \times {10^5}$
(C). $5 \times {10^5}$
(D). $32 \times {10^5}$

Answer 1

Bacterial binary fission is the process that bacteria use to carry out cell division. The question can be solved by simple logic and general multiplication methods.

Complete answer:
Let’s consider that there is a single bacterium in the culture, which means:-
$1 \times {10^5} \to 175$
Now, it is given in the question, that after 35 minutes, the culture will contain $2 \times 1 \times {10^5}$ cells/ml.

Therefore, after $175$ minute, the culture will grow in
$\Rightarrow \frac{{175}}{{35}} = 5$

Thus, the number of cells will be ${2^5} \times {10^5}$ i.e, $32 \times {10^5}$ is the cell concentration after that period.

Note:
Bacteria are said to be prokaryotic organisms and their mode of cell division is amitotic. This process of amitosis generally occurs in lower order organisms. Some vital requirements for growth of bacteria are food, temperature, salt level, water, time and many others. Spore forming ability is also seen in some bacteria, for example Clostridium botulinum. Bacterial cell division is the process in which a bacterial cell is split into two daughter cells, each with a copy of the chromosome. Segregation or separation of the chromosome occurs as they move to opposite ends of the cell during the cell separation process. Here the method used is the General multiplication method. Bacteria cell count requires spectrophotometer procedures by measuring some turbidity changes. Plating method is also very efficient for counting bacteria which is based on the number of colonies formed.