Assume That You Are Trying to Insert a Gene into a Plasmid

question 2

Multiple Choice

Assume that you are trying to insert a gene into a plasmid. Someone gives you a preparation of genomic DNA that has been cut with restriction enzyme X. The gene you wish to insert has sites on both ends for cutting by restriction enzyme Y. You have a plasmid with a single site for Y, but not for X. Your strategy should be to

• A) insert the fragments cut with restriction enzyme X directly into the plasmid without cutting the plasmid.
• B) cut the plasmid with restriction enzyme X and insert the fragments cut with restriction enzyme Y into the plasmid.
• C) cut the DNA again with restriction enzyme Y and insert these fragments into the plasmid cut with the same enzyme.
• D) cut the plasmid twice with restriction enzyme Y and ligate the two fragments onto the ends of the DNA fragments cut with restriction enzyme X.
• E) cut the plasmid with restriction enzyme X and then insert the gene into the plasmid.

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Definitions:

Intermittent Reinforcement

A conditioning schedule where a behavior is reinforced only some of the time, leading to more resistant and persistent responses.

Primary Reinforcement

A naturally rewarding stimulus, such as food or water, that satisfies a basic biological need and hence reinforces a behavior directly.

Secondary Reinforcement

A process in conditioning where a stimulus reinforces a behavior after it has been associated with a primary reinforcer.

Variable Ratio Schedule

A reinforcement schedule used in conditioning where a response is reinforced after an unpredictable number of responses, leading to high and steady response rates.