34 Cloning Overview and Plasmid Vectors

Question

Answer

What is molecular cloning?

Making many copies of a chosen DNA sequence, often using a recombinant plasmid in bacteria.

What are the main cloning steps?

Amplify DNA, cut insert and vector, ligate, transform cells, then select or screen.

Why use PCR before cloning?

To amplify the desired DNA fragment.

What do restriction enzymes do in cloning?

Cut DNA at specific sequences to prepare compatible insert and vector ends.

What does DNA ligase do?

Covalently joins DNA fragments by sealing the sugar-phosphate backbone.

What is a plasmid vector?

A small DNA carrier used to deliver and replicate a gene of interest in a host.

What is the purpose of a plasmid origin of replication?

Allows the plasmid to be copied in the host cell.

What is a selectable marker?

A gene or trait that lets researchers identify or select cells carrying the vector.

Give an example of a plasmid selectable marker.

An antibiotic resistance gene.

Why are bacteria useful for cloning?

They grow quickly, are relatively easy to manipulate and can replicate plasmids.

What is transformation in cloning?

Introducing the recombinant plasmid into bacterial cells.

Why select transformed cells?

Not every cell takes up the plasmid; selection enriches cells that did.

What is a recombinant plasmid?

A plasmid joined to an inserted DNA fragment from another source.