Biol 301 Lab 3 quiz

How did we create insulin for diabetics?

Recombinant human insulin produced in E.coli becomes available for diabetes patients

What are plasmids?

Circular, double-stranded pieces of DNA found in bacteria (but also archaea and eukarya) that are separate and replicate separately from the host’s chromosomal DNA (though inside the host

Horizontal gene transfer

Plasmid is transferred to neighboring bacteria through conjugation

What are the functions of a plasmid in a lab?

Used as vehicles or vectors to multiply pieces of DNA or to introduce foreign DNA into organisms to make them express genes of interes

Why do we use plasmid in the lab?

1. Can ‘easily’ be modified

2. Can be produced in large quantities from bacterial cultures

3. Can harbor the desired gene, but also a distinguishing gene (i.e. a selectable marker/antibiotics resistance)

What are the 3 basic features of a cloning vector?

1. Origin of replication (promoter equivalent)

2. Antibiotic resistance

3. Multiple cloning site (MCS) – a portion of the

plasmid with many consecutive restriction sites.

What was the original purpose of restriction enzymes?

• To protect bacteria from phages

• Bacteria protect themselves using methylation (or restriction sites not in genome)

Restriction enzyme site properties?

• Palindromic

• 4-8 bp long

What was the earlier use of restriction enzymes?

Cut the DNA into small pieces for easier analysis

Smal & EcoRI & DNA ligase functions

Issue with blunt-end ligation in a lab?

No orientation

Recombining DNA fragments using restriction enzymes and DNA ligase (not a question)