Question 1

Which experiment first demonstrated that a 'transforming principle' from virulent bacteria could make avirulent bacteria pathogenic, and that this change was heritable?

Accepted Answer

The Griffith experiment

Question 2

Avery, MacLeod, and McCarty showed that the 'transforming principle' was destroyed by which treatment, indicating the molecule responsible for heredity?

Accepted Answer

DNase treatment

Question 3

In the Hershey-Chase experiment, what was the key evidence that DNA, not protein, is the genetic material?

Accepted Answer

Only the radioactive phosphorus entered the bacteria

Question 4

Which of the following best explains why electron microscopes have higher resolution than light microscopes?

Accepted Answer

Electrons have a shorter wavelength than visible light

Question 5

Which of the following is a correct size range for most microbes?

Accepted Answer

$$0.2\ \mu m to a $$few $$mm$$

Question 6

Which of the following statements about prokaryotes is TRUE?

Accepted Answer

They lack a nucleus and membrane-bound organelles

Question 7

Carl Woese revolutionized microbial taxonomy by using which molecular marker to classify organisms?

Accepted Answer

16S rRNA gene

Question 8

Which of the following is NOT a criterion for something to be considered a microbe?

Accepted Answer

It is always a single-celled organism

Question 9

Which of the following best describes the main advantage of using molecular classification (such as rRNA sequencing) over traditional morphological classification for microbes?

Accepted Answer

Molecular classification reveals evolutionary relationships not visible by morphology

Question 10

Which of the following statements about the three domains of life is supported by rRNA analysis?

Accepted Answer

Archaea share a more recent common ancestor with Eukarya than with Bacteria

Question 11

Which type of microscopy would be most appropriate for visualizing the surface structure of a virus at nanometer resolution?

Accepted Answer

Scanning electron microscopy (SEM)

Question 12

A marine sulfur bacterium, Thiomargarita namibiensis, challenges the definition of a microbe because:

Accepted Answer

It is visible to the naked eye due to its large size

Question 13

Which of the following is a unique feature of Archaea compared to Bacteria and Eukaryotes?

Accepted Answer

Ability to live in extreme environments

Question 14

Which of the following best describes the impact of cyanobacteria on Earth's history?

Accepted Answer

They produced oxygen, leading to the oxygenation of the atmosphere

Question 15

Which of the following is a correct statement about the resolution limit of light microscopy?

Accepted Answer

It is limited by the wavelength of visible light, approximately $$400-700\ nm$$

Question 16

Which of the following is NOT a reason why viruses are debated as 'living' organisms?

Accepted Answer

They can reproduce independently

Question 17

Which of the following is a plausible reason why early scientists doubted DNA could be the genetic material?

Accepted Answer

DNA was thought to be too simple a molecule

Question 18

Which of the following best describes the function of the 16S rRNA gene in prokaryotes?

Accepted Answer

It is essential for protein synthesis as part of the ribosome

Question 19

Which of the following statements about microbial taxonomy is FALSE?

Accepted Answer

It is only based on visible traits

Question 20

Methanogenic archaea are important in which of the following real-world scenarios?

Accepted Answer

Methane production in the mammalian gut

Foundations of Microbiology: Microbial Diversity, Classification, and the Molecular Basis of Heredity

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