Q: Which formula correctly represents the calculation of atomic mass?

$\text{Atomic mass} = \text{Number of protons} + \text{Number of neutrons}$

Question 1

Which experiment provided strong evidence against the theory of spontaneous generation by demonstrating that microbes do not appear in sterilized broth unless exposed to pre-existing life?

Accepted Answer

Pasteur's swan-neck flask experiment

Question 2

According to Koch's postulates, which of the following is NOT required to establish that a specific microbe causes a particular disease?

Accepted Answer

The organism must be able to survive outside the host for at least 24 hours.

Question 3

Which of the following relationships describes a scenario where one organism benefits and the other is neither helped nor harmed?

Accepted Answer

Commensalism

Question 4

A scientist discovers a new microbe that is unicellular, lacks a nucleus, and thrives in extreme environments. To which domain does this organism most likely belong?

Accepted Answer

Archaea

Question 5

Which of the following is a key function of the human microbiota that helps protect against infectious diseases?

Accepted Answer

Defending against microbial pathogens

Question 6

Which statement best describes the process of biofilm formation on a medical device?

Accepted Answer

Microbes attach to the surface, replicate, produce a sticky matrix, and eventually detach as free-floating cells.

Question 7

Which ranking system correctly orders the major taxonomic categories from broadest to most specific?

Accepted Answer

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Question 8

Which of the following statements about isotopes is correct?

Accepted Answer

Isotopes of an element have different numbers of neutrons.

Question 9

A molecule of sodium chloride ($\mathrm{NaCl}$) is held together by which type of chemical bond?

Accepted Answer

Ionic bond

Question 10

Which formula correctly represents the calculation of atomic mass?

Accepted Answer

$	ext{Atomic mass} = 	ext{Number of protons} + 	ext{Number of neutrons}$

Question 11

Which of the following is a plausible consequence of disrupting the normal microbiota with antibiotics?

Accepted Answer

Decreased defense against microbial pathogens

Question 12

Which of the following best describes mutualism in the context of human microbiota?

Accepted Answer

Microbes provide benefits to the host, such as vitamin production, while receiving nutrients and a habitat.

Question 13

Which of the following statements about electrons is correct?

Accepted Answer

Electrons have a negative charge and negligible mass.

Question 14

A scientist wants to classify a newly discovered organism. It is multicellular, eukaryotic, and photosynthetic. Which kingdom is it most likely to belong to?

Accepted Answer

Plantae

Question 15

Which of the following is NOT a function of the human microbiota?

Accepted Answer

Causing infectious diseases

Question 16

Which process describes the initial step in biofilm formation?

Accepted Answer

Attachment of cells to a surface

Question 17

Which of the following best explains why transient microbiota can be removed through hygiene practices?

Accepted Answer

They are temporary residents and do not form strong attachments.

Question 18

Which of the following is true regarding binomial nomenclature?

Accepted Answer

It was developed by Linnaeus and uses two names: genus and species.

Question 19

If two organisms share at least 97% of a specific rRNA sequence and 70% of the same DNA sequence, what does this indicate?

Accepted Answer

They are considered the same species.

Question 20

Which of the following best describes the role of growth media in microbiology?

Accepted Answer

It is a mixture of nutrients that supports the growth of organisms in an artificial setting.

Foundations of Microbiology: Classification, Microbiota, and Atomic Structure

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