# DBT JRF 2020 — Question 14

Exam: DBT JRF 2020 · Section: B · Topic: Microbiology · Difficulty: Medium

## Question

A bacterial population, growing in batch culture, increases from 1000 cells to 10,00,000 cells in 5 hours. What is the generation time of the bacteria?

## Options

- **A.** 45 min
- **B.** 30 min
- **C.** 22 min
- **D.** 9 min

## Answer

Option B

## Explanation

Bacterial population growth: $N_t = N_0 \times 2^n$ , where $n$ = number of generations. $\dfrac{N_t}{N_0} = \dfrac{10^6}{10^3} = 10^3$ . Number of generations: $2^n = 1000 \Rightarrow n = \log_2(1000) = \dfrac{\log 1000}{\log 2} = \dfrac{3}{0.301} \approx 9.97 \approx 10$ generations. Total time = 5 hours = 300 min. Generation time $g = \dfrac{300 \text{ min}}{10} = 30 \text{ min}$ .

Source: https://mypyqbuddy.com/questions/a-bacterial-population-growing-in-batch-culture-increases-6a05a8a02adafec470293226