Question 1

Which of the following is NOT a major contribution of microbes to life on Earth?

Accepted Answer

They are the only organisms responsible for animal evolution.

Question 2

During the Golden Age of Microbiology (1854–1914), which of the following was a significant achievement?

Accepted Answer

Validation of the germ theory of disease.

Question 3

Which scientist is credited with demonstrating that DNA is the transforming material in bacteria?

Accepted Answer

Oswald Avery

Question 4

Which of the following best describes the function of 16S ribosomal RNA in phylogenetic studies?

Accepted Answer

It is a highly conserved RNA present in all living cells, making it ideal for evolutionary comparisons.

Question 5

Which of the following is a key assumption of the molecular clock approach in molecular phylogeny?

Accepted Answer

The average mutation rate is constant across generations.

Question 6

A researcher is classifying a newly discovered microbe. Which combination of characteristics would be most useful for initial classification?

Accepted Answer

Morphology and metabolic properties

Question 7

Which of the following statements about the three domains of life is correct?

Accepted Answer

Eukarya and Archaea share a more recent common ancestor than either does with Bacteria.

Question 8

Which of the following is a limitation of using stromatolites as geological evidence for early life?

Accepted Answer

Some layered formations attributed to stromatolites may be formed by abiotic processes.

Question 9

Which metabolic classification describes an organism that obtains energy from inorganic compounds and carbon from CO$$_2$$?

Accepted Answer

Chemoautotroph (Lithotroph)

Question 10

Why are not all microbes culturable in the laboratory?

Accepted Answer

They require specific environmental conditions that are difficult to replicate.

Question 11

Which of the following is NOT a property of a good phylogenetic marker?

Accepted Answer

It is frequently transferred between species.

Question 12

Which of the following best explains why phylogenetic trees are considered models rather than proofs of evolutionary relationships?

Accepted Answer

They are constructed using assumptions and available data, which may change with new evidence.

Question 13

Which of the following realities can distort the validity of the molecular clock approach?

Accepted Answer

Variable mutation rates among lineages

Question 14

Which of the following is a real-world application of microbes in environmental science?

Accepted Answer

Using microbes as catalysts to remediate contaminated soil

Question 15

Which of the following best describes the role of microbes in the carbon cycle?

Accepted Answer

They both fix and release carbon through various metabolic processes.

Question 16

Which of the following Nobel Prize-winning discoveries is most directly related to the use of bacterial enzymes in molecular biology?

Accepted Answer

Development of PCR (polymerase chain reaction)

Question 17

A scientist is using the molecular clock approach to estimate the divergence time between two bacterial species. Which equation would best represent the relationship between genetic distance ($$d$$), mutation rate ($$1$$), and time ($$t$$)?

Accepted Answer

$$d = 1 	imes t$$

Question 18

Which of the following is a reason why microbes are considered excellent model organisms for studying fundamental biological processes?

Accepted Answer

They grow to high numbers and are easy to manipulate.

Question 19

Which of the following statements about the discovery of viruses is correct?

Accepted Answer

Viruses were first identified as filterable infective particles.

Question 20

Which of the following best describes the impact of the microbiome on human health?

Accepted Answer

The microbiome is critical for both health and disease.

Micro: Lecture 1: 1/12

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