A Microbiologist Is Working with Two Separate Cultures of the Same

question 23

Multiple Choice

A microbiologist is working with two separate cultures of the same organism. The bacteria in one culture are resistant to penicillin, whereas the bacteria in the other culture are susceptible to penicillin. The bacteria from both cultures are mixed together, and all the resulting bacteria are resistant to penicillin. What caused this phenomenon?

• A) The plasmid carrying the resistance gene was transferred to the susceptible population of bacteria.
• B) The plasmid carrying the susceptibility gene was transferred to the resistant population of bacteria.
• C) An IS element was inserted into the genome of the susceptible bacterial population.
• D) A frame-shift mutation occurred that allowed the susceptible population of bacteria to develop resistance to penicillin.

Understand the differences between observational studies and experiments.

Recognize the impact of study design on the validity of conclusions.

Identify key elements of experimental design, such as randomization, blinding, and control.

Understand the concept of and identify examples of confounding and lurking variables.

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Definitions:

Moisturizing Lotion

A topical preparation used to hydrate and soften the skin, helping to prevent dryness and irritation.

Oral Thrush

A fungal infection in the mouth, characterized by white patches on the tongue and inside the cheeks.

Antiseptic Mouthwash

A liquid solution used in oral hygiene to kill bacteria and other microorganisms in the mouth, reducing infection and bad breath.

Impaired Dentition

A condition characterized by the deterioration of dental health, affecting an individual's ability to chew and sometimes speak clearly.