Question 1

Which of the following statements about binary fission is FALSE?

Accepted Answer

It generates genetically diverse daughter cells.

Question 2

A culture of E. coli is started with 100 cells. If the generation time is 20 minutes, how many cells will there be after 2 hours under optimal conditions? Use the formula $$N_f = (N_i)2^n$$ where $$n is $$the number of generations.

Accepted Answer

6,400

Question 3

Which phase of bacterial growth in a closed batch system is characterized by a balance between cell division and cell death?

Accepted Answer

Stationary phase

Question 4

A Salmonella species is grown for 8 hours. In this time, each cell divides about four times. What is the generation time in minutes? Use the formula $$	ext{Generation time} = \frac{	ext{Growth time (min)}}{	ext{Number of generations}}.$$

Accepted Answer

30 minutes

Question 5

Which of the following best describes a mesophile?

Accepted Answer

Thrives at temperatures between 10°C and 50°C

Question 6

Which of the following is a correct match between a microbe and its pH preference?

Accepted Answer

Acidophile: pH 1–5

Question 7

A bacterium that can tolerate high salt concentrations but does not necessarily grow best in them is called a:

Accepted Answer

Facultative halophile

Question 8

Which enzyme is responsible for converting superoxide ions ($$O_2$$^-$$) to hydrogen peroxide (H_2O_2$) in aerobic bacteria?

Accepted Answer

Superoxide dismutase

Question 9

Which of the following best explains why Mycobacterium leprae primarily infects cooler regions of the body such as the ears, hands, and feet?

Accepted Answer

It grows best at lower temperatures found in the extremities.

Question 10

Which of the following media would be best for isolating a Gram-negative bacterium from a mixed sample?

Accepted Answer

Eosin methylene blue (EMB) agar

Question 11

A patient’s wound sample is being collected for anaerobic culture. Which of the following is NOT a necessary consideration?

Accepted Answer

Using complex media such as FTM

Question 12

Which of the following statements about autoclaving is TRUE?

Accepted Answer

It sterilizes by applying steam heat at 121°C and 15 psi.

Question 13

Which of the following best describes the function of a chemostat in industrial microbiology?

Accepted Answer

It keeps cells in a continuous state of logarithmic (log) growth.

Question 14

Which of the following is a direct method for enumerating microbial populations?

Accepted Answer

Viable plate count (CFU/mL)

Question 15

Which of the following best describes a photoautotroph?

Accepted Answer

Uses sunlight for energy and CO$$_2$$ for carbon

Question 16

Which of the following is the most effective method for eliminating bacterial endospores?

Accepted Answer

Autoclaving at 121°C and 15 psi

Question 17

A bacterium that grows only at the top of a fluid thioglycolate medium tube is most likely a(n):

Accepted Answer

Obligate aerobe

Question 18

Which of the following best explains why selective media are used in clinical microbiology?

Accepted Answer

To foster the growth of certain bacteria while suppressing others

Question 19

Which of the following is a correct match between a germicide and its use?

Accepted Answer

Disinfectant: used on inanimate objects

Question 20

Which of the following is a plausible reason why knowing the generation time of a pathogen is important in healthcare?

Accepted Answer

It helps estimate how many harmful cells are present and guides treatment options.

Fundamentals of Microbial Growth: Structured Study Notes

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