Question 1

Which of the following best describes the concept of a molecular clock in microbial evolution?

Accepted Answer

It estimates evolutionary divergence based on the accumulation of genetic mutations over time.

Question 2

Horizontal gene transfer (HGT) challenges the traditional definition of species because:

Accepted Answer

It allows genes to move freely between different species, complicating vertical inheritance.

Question 3

Which of the following is NOT a cause of genome variation in microbes?

Accepted Answer

Protein denaturation

Question 4

In the context of microbial taxonomy, which criterion is used to define a prokaryotic species?

Accepted Answer

All of the above

Question 5

If strain A has 50 genes and strain B has 45 genes, and the core genome has 20 genes, what is the size of the pan genome?

Accepted Answer

95 genes

Question 6

Which of the following statements about experimental evolution using microbes is TRUE?

Accepted Answer

It allows direct observation of evolutionary processes over short time scales.

Question 7

Which of the following is a stage in the evolution of a new trait according to experimental evolution studies?

Accepted Answer

All of the above

Question 8

Why are microbes ideal for studying evolution in the laboratory?

Accepted Answer

They have short generation times and can be genetically and environmentally manipulated.

Question 9

Which genes are most likely to be transmitted vertically rather than horizontally?

Accepted Answer

Informational genes

Question 10

Natural selection acts on:

Accepted Answer

Pre-existing variation within populations

Question 11

In the MRSA case study, after 12 weeks of antibiotic treatment, the evolved small-colony variant was:

Accepted Answer

More resistant to antibiotics than the original strain

Question 12

Which of the following is required for adaptive evolution to occur?

Accepted Answer

Variation, selection, and a large number of generations

Question 13

Which of the following can distort the validity of the molecular clock approach to relatedness?

Accepted Answer

Horizontal gene transfer between species

Question 14

Which of the following is NOT a principle of taxonomy?

Accepted Answer

Gene duplication

Question 15

Which of the following is a nongenetic method of categorizing microbes?

Accepted Answer

Phenotypic categories

Question 16

Which of the following best explains why dichotomous keys are still used for classification and identification?

Accepted Answer

They provide a simple, stepwise approach based on observable traits.

Question 17

Which of the following is a real-world example of adaptive evolution in microbes?

Accepted Answer

Development of antibiotic resistance in MRSA

Question 18

Which of the following is TRUE regarding pan and core genomes?

Accepted Answer

Pan genomes contain all genes found in any member of a species.

Question 19

Which of the following evolutionary mechanisms is most likely to result in paralogous genes?

Accepted Answer

Gene duplication

Question 20

Which of the following is a limitation of using SSU rRNA similarity for species identification?

Accepted Answer

It cannot distinguish between closely related species with high similarity.

Micro: Lecture 2 1/14

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