Question

A bacterium divides every 35 minutes. If a culture containing ${10^5}$cells/$mL$is grown for 175 minutes, what will be the cell concentration/$mL$after 175 minutes?
(A) $5 \times {10^5}$cells
(B) $35 \times {10^5}$cells
(C) $32 \times {10^5}$cells
(D) $4.175 \times {10^5}$cells

Answer 1

Hint: For solving the given equation, use basic math. Always remember that when a bacteria divides by a mitotic division, it divides into 2 cells instead of 1.

Complete step by step answer: Total time given is 175 minutes. As already given that a bacterium divides every 35 minutes. Therefore, total division would be: $\tfrac{{175}}{{35}} = 5$ {This is the generation calculated}. After 35 minutes, the culture will have $2 \times {10^5}$cells/$mL${bacteria divides into 2 cells by binary fission}. Similarly, after 175 minutes (5 generations), the number of cells will be ${2^5} \times {10^5}$cells/$mL$ which is,$32 \times {10^5}$ cells/$mL$.

Additional information: ‘Culture medium’ or ‘Growth medium’ is a liquid or gel designed to support the growth of microorganisms like bacteria or yeast. There are different types of media suitable for growing different types of cells. The most common growth media for microorganisms are nutrient broths (liquid nutrient medium) or LB medium (Lysogeny broth). Liquid media are often mixed with agar and poured via a sterile media dispenser into Petri dishes to solidify. These agar plates provide a solid medium on which microbes may be cultured. Different types of Culture Medium:-
a. Basal media
b. Enriched media
c. Selective media
d. Indicator media
e. Transport media
f. Storage media
Hence, the correct answer is option C.

Note: Bacteria divide into two identical daughter cells by the process of Binary fission. It is an asexual mode of reproduction. During the process, the bacterial chromosome replicates and the two copies are attached to different parts of the cell membrane. The bacterial cell begins to pull apart, separating the two copies of the chromosomes.