Question 1

Bioremediation ________ by introducing pollutant-consuming microorganisms or specific nutrients that help microorganisms degrade pollutants.
A) accelerates the natural cleanup process
B) exploits genetic exchange mechanisms
C) invokes microbial evolution
D) uses chemotaxis of biodegrading microorganisms

Accepted Answer

Bioremediation works by introducing microorganisms or nutrients that help microorganisms degrade pollutants. By doing so, it accelerates the natural cleanup process that occurs in the environment. This is the primary mechanism that makes bioremediation an effective method for cleaning up contaminated sites. The other choices (B, C, and D) are not accurate descriptions of how bioremediation works.

Question 2

Why is it important to use cultivation-independent methods to help understand microbial diversity?
A) It allows researchers to identify species that cannot be grown in culture.
B) It is the only way that phylogenetic trees can be constructed.
C) It must be used after bacteria are cultured to more fully sequence their DNA.
D) It is necessary to be able to examine ribosomal RNA.

Accepted Answer

Cultivation-independent methods are important because many microbial species cannot be grown in culture. These methods, such as metagenomic sequencing or PCR amplification of specific genes, allow for identification of microbial diversity without the need for culturing.

Answer: D
 One of the most common cultivation-independent methods is sequencing of the 16S rRNA gene, which is present in all bacteria and archaea. This method allows for identification and classification of microbial diversity, often to the species or even strain level, without the need to culture the organisms.

Question 3

All microorganisms require molecular oxygen to carry on life functions.

Accepted Answer

Not all microorganisms require oxygen, some are able to live in environments without oxygen (anaerobic).

Question 4

When medical devices are left in the body, bacteria may grow on them as ________, which makes them especially resistant to treatment.
A) biofilms
B) liquids
C) populations
D) communities

Accepted Answer

The answer of When medical devices are left in the...

Question 5

Which of the following types of microscopy could be used to visualize the layers of the cell membrane and the cell wall?
A) phase-contrast microscopy
B) transmission electron microscopy
C) bright-field microscopy
D) confocal microscopy

Accepted Answer

Transmission electron microscopy uses a beam of electrons to image the ultrastructure of cells and can provide high-resolution images of the layers of the cell membrane and the cell wall. Phase-contrast microscopy can enhance contrast of transparent images, bright-field microscopy is best for observing stained samples and confocal microscopy is used for imaging thick specimens.

Question 6

________ produced by microbial fermentation of glucose from cellulose or cornstarch is becoming a more important component of biofuels in the United States, and specialized ________ are needed to make this a commercially available product.
A) Biodiesel / biotechnologists
B) Biodiesel / industrial microbiologists
C) Ethanol / biotechnologists
D) Ethanol / industrial microbiologists

Accepted Answer

The fermentation of glucose from cellulose or cornstarch is used to produce ethanol, which is becoming an important component of biofuels in the United States. Therefore, the correct choice is option D, which describes the need for specialized industrial microbiologists to make this commercially available.

Question 7

Why is ribosomal RNA especially useful for the study of phylogenetic relationships?
A) It is only found in some species, helping to distinguish them from others.
B) It is highly conserved.
C) It is highly variable.
D) It is extremely short.

Accepted Answer

Ribosomal RNA is highly conserved, meaning that it changes slowly over time, which makes it particularly useful for studying evolutionary relationships between different species. Its high level of conservation also allows researchers to compare ribosomal RNA sequences across a wide range of organisms, providing insight into the deep evolutionary history of life on Earth.

Question 8

Microbes that live at high temperatures in hot springs are ________.
A) always Archaea.
B) also able to thrive at low temperatures.
C) called extremophiles.
D) rarely found.

Accepted Answer

Microbes that live at high temperatures in hot springs are known as extremophiles, because they can thrive in extreme environments. It is not necessarily true that they are always Archaea, as some bacteria can also live in hot springs. They are adapted to live at high temperatures, so it is unlikely that they can also thrive at low temperatures. While they may be less common than other types of microbes, they are not necessarily rare.

Question 9

What field focuses specifically on the use of microbes to make products, such as antibiotics, on a large scale?
A) microbial ecology
B) biotechnology
C) industrial ecology
D) medical microbiology

Accepted Answer

The answer of What field focuses specifically on the use...

Question 10

Which statement about the relationship between microbes and humans is FALSE?
A) Most microbes are pathogenic.
B) Infectious disease is an important public health concern.
C) Bacteria in the digestive tract are important for digestion.
D) Microbes in root nodules fix nitrogen and allow plants to make nitrogen-rich products.

Accepted Answer

The statement that most microbes are pathogenic is false. Only a small proportion of microbes are pathogenic, and many are actually beneficial to human health.

Question 11

________ was the first to identify a new form of autotrophy in which energy is obtained from oxidizing inorganic compounds called ________.
A) Martinus Beijerinck / heteroautotrophy
B) Martinus Beijerinck / chemolithotrophy
C) Sergei Winogradsky / heteroautotrophy
D) Sergei Winogradsky / chemolithotrophy

Accepted Answer

Sergei Winogradsky was the first to identify a new form of autotrophy called chemolithotrophy in which energy is obtained from oxidizing inorganic compounds. Martinus Beijerinck is known for his work on microbiology and enrichment cultures but is not associated with the discovery of chemolithotrophy. Heteroautotrophy is a different type of nutrition that involves obtaining both carbon and energy from organic sources.

Question 12

Archaea and Bacteria are unified as prokaryotes in lacking ________ which Eukarya contain, such as mitochondria.
A) membranes
B) nuclei
C) membrane-enclosed organelles
D) nuclei and membrane-enclosed organelles

Accepted Answer

Archaea and Bacteria, both prokaryotes, lack nuclei and membrane-enclosed organelles, distinguishing them from Eukarya, which have these cellular structures.

Question 13

Most microorganisms are pathogenic.

Accepted Answer

Most microorganisms are not pathogenic, in fact, only a small percentage of microorganisms cause disease in humans and animals. The vast majority of microorganisms are either harmless or beneficial.

Question 14

Approximately two billion years ago, ________ were primarily responsible for initially oxygenating Earth.
A) algae
B) Archaea
C) cyanobacteria
D) purple sulfur bacteria

Accepted Answer

Cyanobacteria were the first organisms to carry out photosynthesis and release oxygen into the atmosphere, which began approximately two billion years ago. The other options listed did not play a significant role in oxygenating Earth at this time.

Question 15

The production of human proteins (e.g., insulin) by genetically engineered microorganisms is an example of ________, a subdiscipline of microbiology.
A) applied microbiology
B) biotechnology
C) industrial microbiology
D) molecular microbiology

Accepted Answer

The production of human proteins by genetically engineered microorganisms falls within the realm of biotechnology, which involves the use of living organisms to create useful products or carry out specific tasks. This particular application of biotechnology is known as recombinant DNA technology, which is used to manipulate the genetic material of organisms in order to produce specific proteins or other biological molecules. Applied microbiology, industrial microbiology, and molecular microbiology are all related subdisciplines of microbiology, but they do not specifically relate to the production of human proteins using genetically engineered microorganisms.

Question 16

Metabolism is a unifying characteristic of all cellular organisms.

Accepted Answer

Metabolism refers to the chemical processes that occur within a cell or organism to maintain life. As this process is essential for all living organisms, metabolism is a unifying characteristic of all cellular organisms.

Question 17

________ was the first to describe microorganisms, while ________ was the first person to see bacteria.
A) Antoni van Leeuwenhoek / Robert Hook
B) Antoni van Leeuwenhoek / Robert Koch
C) Robert Hooke / Antoni van Leeuwenhoek
D) Robert Koch / Antoni van Leeuwenhoek

Accepted Answer

Robert Hooke was the first to describe microorganisms, while Antoni van Leeuwenhoek was the first person to see bacteria.

Question 18

Which of the following types of microscopy is especially effective for viewing details of internal structures within live cells?
A) phase-contrast microscopy
B) transmission electron microscopy
C) bright-field microscopy
D) scanning electron microscopy

Accepted Answer

Phase-contrast microscopy is especially effective for viewing details of internal structures within live cells. It uses phase shifts caused by differences in refractive indices to enhance contrast and reveal organelles and other internal structures that are not visible with other types of microscopy. Transmission electron microscopy and scanning electron microscopy are both useful for viewing external structures and details at high resolution, but they require samples to be fixed and/or coated with metal, which kills the cells. Bright-field microscopy is a basic form of microscopy that does not provide enough contrast to view internal structures in live cells.

Question 19

Who was the first researcher to provide direct experimental data that supported the germ theory to explain infectious disease?
A) Pasteur
B) Winogradsky
C) Lister
D) Koch

Accepted Answer

Robert Koch was the first researcher to provide direct experimental data that supported the germ theory to explain infectious disease. In 1876, he discovered the causative agent of anthrax and developed methods for pure culture isolation of microorganisms, which allowed him to prove the causative relationship between specific microorganisms and specific diseases. This led to the development of Koch's postulates, a set of criteria for establishing the relationship between a specific infectious agent and a specific disease.

Question 20

Electron microscopy has greater ________ than light microscopy, because the wavelength of visible light is much larger than the wavelength of electrons.
A) contrast
B) magnification
C) resolution
D) penetration

Accepted Answer

Electron microscopy has a much smaller wavelength than visible light, allowing for higher resolution in imaging. Contrast, magnification, and penetration can also be improved with electron microscopy, but resolution is the most significant advantage.

Quiz 1: The Microbial World

Bioremediation ________ by introducing pollutant-consuming microorganisms or specific nutrients that help microorganisms degrade pollutants.

Why is it important to use cultivation-independent methods to help understand microbial diversity?

All microorganisms require molecular oxygen to carry on life functions.

When medical devices are left in the body, bacteria may grow on them as ________, which makes them especially resistant to treatment.

Which of the following types of microscopy could be used to visualize the layers of the cell membrane and the cell wall?

produced by microbial fermentation of glucose from cellulose or cornstarch is becoming a more important component of biofuels in the United States, and specialized are needed to make this a commercially available product.

Why is ribosomal RNA especially useful for the study of phylogenetic relationships?

Microbes that live at high temperatures in hot springs are ________.

What field focuses specifically on the use of microbes to make products, such as antibiotics, on a large scale?

Which statement about the relationship between microbes and humans is FALSE?

was the first to identify a new form of autotrophy in which energy is obtained from oxidizing inorganic compounds called .

Archaea and Bacteria are unified as prokaryotes in lacking ________ which Eukarya contain, such as mitochondria.

Most microorganisms are pathogenic.

Approximately two billion years ago, ________ were primarily responsible for initially oxygenating Earth.

The production of human proteins (e.g., insulin) by genetically engineered microorganisms is an example of ________, a subdiscipline of microbiology.

Metabolism is a unifying characteristic of all cellular organisms.

was the first to describe microorganisms, while was the first person to see bacteria.

Which of the following types of microscopy is especially effective for viewing details of internal structures within live cells?

Who was the first researcher to provide direct experimental data that supported the germ theory to explain infectious disease?

Electron microscopy has greater ________ than light microscopy, because the wavelength of visible light is much larger than the wavelength of electrons.