The following questions refer to Figure 27.1.
In this eight-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population.

Figure 27.1
-If the experimental population of E. coli lacks an F factor or F plasmid, and if bacteriophages are excluded from the bacterial cultures, then which of these is (are)means by which beneficial mutations might be transmitted horizontally to other E. coli cells?
A) via sex pili
B) via transduction
C) via conjugation
D) via transformation
E) Two of the responses above are correct.

Question

The following questions refer to Figure 27.1.
In this eight-year experiment, 12 populations of E. coli, each begun from a single cell, were grown in low-glucose conditions for 20,000 generations. Each culture was introduced to fresh growth medium every 24 hours. Occasionally, samples were removed from the populations, and their fitness in low-glucose conditions was tested against that of members sampled from the ancestral (common ancestor) E. coli population.
  
Figure 27.1
-If the experimental population of E. coli lacks an F factor or F plasmid, and if bacteriophages are excluded from the bacterial cultures, then which of these is (are)means by which beneficial mutations might be transmitted horizontally to other E. coli cells?
A) via sex pili 
B) via transduction 
C) via conjugation 
D) via transformation 
E) Two of the responses above are correct.

Quizplus · Accepted Answer

Since the experimental population lacks an F factor or F plasmid, conjugation cannot occur. Sex pili are used for conjugation, so they are also not a means of transmitting beneficial mutations. Bacteriophages are excluded from the cultures, so transduction cannot occur. The only means left is transformation, which involves the uptake of genetic material from the environment by the bacteria. Therefore, the correct answer is D) via transformation.

The Following Questions Refer to Figure 27.1