Question 1

A bacterial culture is transferred from a nutrient-rich medium to a fresh medium. After several hours, the cell count remains unchanged, but the cells are larger and have increased enzyme activity. Which growth phase is the culture in?

Accepted Answer

Lag phase

Question 2

Which of the following best describes a chemolithoautotroph?

Accepted Answer

An organism that oxidizes inorganic molecules for energy and uses CO$$_2 as $$its carbon source

Question 3

A bacterium is placed in distilled water containing lysozyme. What is the most likely outcome, and why?

Accepted Answer

The cell will swell and burst because lysozyme weakens the cell wall in a hypotonic environment

Question 4

Which of the following statements about Gram-negative bacteria is correct?

Accepted Answer

They have an outer membrane containing lipopolysaccharide (LPS) and a thin peptidoglycan layer

Question 5

A facultative anaerobe is inoculated into thioglycolate medium. Where would you expect to see the most growth?

Accepted Answer

Mostly near the top, but some growth throughout the tube

Question 6

Which of the following best describes the function of fimbriae in bacteria?

Accepted Answer

Attachment to surfaces

Question 7

A microbe isolated from a salt evaporation pond grows only in media containing 15\% NaCl and dies in standard broth. What is the best classification for this organism?

Accepted Answer

Obligate halophile

Question 8

Which of the following media would you use to isolate an obligate anaerobe from a mixed sample?

Accepted Answer

Reducing medium

Question 9

A unicellular eukaryote is motile, has mitochondria, and lacks chloroplasts. What is the most likely classification?

Accepted Answer

Protozoan

Question 10

Which of the following is a distinguishing feature of Archaea compared to Bacteria?

Accepted Answer

Ability to live in extreme environments such as high temperature and acidity

Question 11

Which of the following best describes the stationary phase of bacterial growth?

Accepted Answer

The rate of cell division equals the rate of cell death

Question 12

A bacterium that requires oxygen but only at low concentrations is classified as a:

Accepted Answer

Microaerophile

Question 13

Which of the following statements about quorum sensing is correct?

Accepted Answer

It allows microbes to detect population density using signaling molecules

Question 14

Which of the following is true about the bacterial nucleoid?

Accepted Answer

It is the region where the chromosome is located

Question 15

A bacterium with a comma-shaped morphology is best described as a:

Accepted Answer

Vibrio

Question 16

Which of the following statements about mannitol salt agar is correct?

Accepted Answer

It is both selective and differential

Question 17

A bacterium is connected to another cell by a rigid, tubular structure and is transferring DNA. What is this structure called, and what process is occurring?

Accepted Answer

Sex pilus; conjugation

Question 18

Which of the following would be most affected by a hypotonic environment due to the absence of a cell wall?

Accepted Answer

Protozoa

Question 19

Which of the following is a function of the Golgi apparatus in eukaryotic cells?

Accepted Answer

Receiving, modifying, and packaging proteins

Question 20

A microbe that grows optimally at 37 $$^\circC $$and is commonly associated with human disease is most likely a:

Accepted Answer

Mesophile

Microbial Nutrition, Growth, and Cell Structure: Study Notes

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