Use the Following to Answer Questions

question 30

Multiple Choice

Use the following to answer questions
A scientist carries out a ligation reaction designed to insert a foreign piece of DNA into a plasmid that contains the front end of the lacZ gene within the multiple cloning site (MCS) . He carries out three transformations in parallel with lacZ^- bacteria. The three transformations (i, ii, and iii) contain the following:
i. sterile water
ii. a sample of the original plasmid
iii. the ligation reaction
He then plates the transformations on medium containing X-gal and ampicillin.
-The scientist observed colonies on plate (i) . Which of the following might be reasons(s) for this? (Select all that apply.)

• A) The plasmid he used has a kanamycin resistance marker instead of an ampicillin resistance marker.
• B) He transformed cells that were not actually ampicillin sensitive.
• C) Too high a concentration of ampicillin was added to the plates.
• D) Too low a concentration of ampicillin was added to the plates.
• E) The water sample was contaminated with the original plasmid.

---

Definitions:

Variable

A concept that can take on more than one value.

Selective Observation

The tendency to notice or focus on information that confirms one’s preconceptions, while ignoring contradictory evidence.

Automobile Accident

An unexpected, undesirable event involving a vehicle, often leading to damage or injury, and attributed to human error, environmental conditions, or technical failure.

Observers

Individuals or entities that watch or monitor activities, events, or behaviors without directly participating.