Question 1

Which of the following best describes a chemoheterotroph?

Accepted Answer

An organism that uses organic compounds as both an energy and carbon source.

Question 2

A bacterium isolated from a volcanic hot spring grows optimally at 90$$^	ext{o}C. $$How would you classify this organism based on its temperature preference?

Accepted Answer

Hyperthermophile

Question 3

Which of the following is a major risk to microbial cells when exposed to extreme pH values?

Accepted Answer

Denaturation of proteins

Question 4

A microbe that can survive in high salt concentrations, but does not require it, is best described as a:

Accepted Answer

Facultative halophile

Question 5

Which of the following equations correctly represents the reaction catalyzed by catalase?

Accepted Answer

$$2H_2O_2 \rightarrow 2H_2O + O_2$$

Question 6

Which trace element is commonly required as a cofactor for enzymes involved in electron transport?

Accepted Answer

Iron (Fe)

Question 7

A bacterium that grows only at the bottom of a thioglycolate broth tube is most likely a(n):

Accepted Answer

Obligate anaerobe

Question 8

Which of the following best explains why salted fish and honey are effective at preventing microbial growth?

Accepted Answer

They create a hypertonic environment, causing water to leave microbial cells.

Question 9

Which enzyme is responsible for converting superoxide radicals to hydrogen peroxide in aerobic bacteria?

Accepted Answer

Superoxide dismutase (SOD)

Question 10

A microbe isolated from acidic mine drainage grows optimally at pH 1.5. How would you classify this organism?

Accepted Answer

Acidophile

Question 11

Which of the following is NOT a major chemical requirement for microbial growth?

Accepted Answer

Helium

Question 12

Which group of microbes is most likely to cause human disease?

Accepted Answer

Mesophiles

Question 13

Which of the following best describes an autotroph?

Accepted Answer

An organism that uses CO$$_2 as a $$carbon source.

Question 14

A bacterium that can grow in the presence or absence of oxygen, but grows better with oxygen, is classified as a:

Accepted Answer

Facultative anaerobe

Question 15

Which of the following is a real-world example of a hypertonic environment used for food preservation?

Accepted Answer

Salted fish

Question 16

Which of the following statements about trace elements is TRUE?

Accepted Answer

They are usually provided as ions and serve as enzyme cofactors.

Question 17

Which of the following best describes the role of phosphorus in microbial cells?

Accepted Answer

Component of nucleic acids and phospholipids

Question 18

A microbe that grows best at low oxygen concentrations, but not in the absence of oxygen, is classified as a:

Accepted Answer

Microaerophile

Question 19

Which of the following is a correct statement about the effect of temperature on microbial growth?

Accepted Answer

Enzyme denaturation occurs at temperatures above the maximum growth temperature.

Question 20

Which of the following best explains why obligate anaerobes are killed by oxygen?

Accepted Answer

They lack the enzymes superoxide dismutase and catalase.

Microbial Nutrition & Growth: Requirements for Microbial Growth

Study Guide - Practice Questions

Study Guide - Flashcards