Question 1

Which of the following best describes a biofilm and its significance in clinical settings?

Accepted Answer

A biofilm is a collection of microbes living on a surface in a complex community, often making infections harder to treat due to increased resistance.

Question 2

Which group of organisms uses light as an energy source and carbon dioxide as a carbon source?

Accepted Answer

Photoautotrophs

Question 3

A bacterium is placed in a hypertonic solution. What is the most likely outcome?

Accepted Answer

The cell will shrivel as water leaves the cell.

Question 4

Which of the following is NOT a toxic form of oxygen?

Accepted Answer

Molecular oxygen ($$O_2)$$

Question 5

A microorganism grows best at pH 5.6. Which term best describes this organism?

Accepted Answer

Acidophile

Question 6

Which of the following media would you use to distinguish between bacteria that ferment lactose and those that do not?

Accepted Answer

Differential media

Question 7

What is the primary reason obligate anaerobes cannot survive in the presence of oxygen?

Accepted Answer

Oxygen causes irreparable damage due to toxic forms of oxygen acting as oxidizing agents.

Question 8

Which of the following best describes the generation time of a bacterial cell?

Accepted Answer

The time required for a bacterial cell to grow and divide.

Question 9

A culture medium that contains substances favoring the growth of certain microorganisms while inhibiting others is called:

Accepted Answer

Selective media

Question 10

Which method would be most appropriate for estimating the number of bacteria in a water sample with very low bacterial concentration?

Accepted Answer

Membrane filtration

Question 11

Which of the following statements about nitrogen fixation is correct?

Accepted Answer

Nitrogen fixation is essential to life on Earth and is carried out by certain bacteria.

Question 12

A bacterial culture is transferred from a 2-week-old 'death-phase' sample into fresh media. Why might growth occur?

Accepted Answer

Some cells survive the death phase and can resume growth when provided with fresh nutrients.

Question 13

Which of the following best describes the relationship between temperature and microbial growth rate?

Accepted Answer

Growth rate increases with temperature up to an optimum, then decreases sharply as temperature exceeds the optimum.

Question 14

Which type of microorganism would you expect to find thriving in deep-sea hydrothermal vents with extreme pressure?

Accepted Answer

Barophiles

Question 15

A microbiologist wants to isolate a single bacterial species from a mixed sample. Which technique is most appropriate?

Accepted Answer

Streak plate method

Question 16

Which equation best represents the exponential growth of bacteria by binary fission, where $$N is $$the final number of cells, $$N_0 is $$the initial number of cells, and $$n is $$the number of generations?

Accepted Answer

$$N = N_0$ 	imes 2^n$$

Question 17

Which of the following is a direct method for measuring microbial reproduction that does NOT require incubation?

Accepted Answer

Microscopic counts

Question 18

Which of the following best explains why cardiac nurses and respiratory therapists should care about biofilms?

Accepted Answer

Biofilms can form on medical devices and mucous membranes, increasing the risk of persistent infections.

Question 19

Which of the following is a plausible reason why most cells die in the absence of water?

Accepted Answer

Water is necessary to dissolve enzymes and nutrients for cellular processes.

Question 20

Which of the following best describes the function of quorum sensing in biofilm formation?

Accepted Answer

Quorum sensing allows bacteria to detect and respond to cell density, triggering production of extracellular matrix and coordinated behavior.

Microbial Nutrition and Growth: Study Notes for College Microbiology

Study Guide - Practice Questions

Study Guide - Flashcards