Topic 3

Question 1

cloning vector

Answer 1

• small piece of DNA that can be added and maintained in an organism
• can insert foreign DNA into it too

Question 2

restriction enzyme

Answer 2

• protein that breaks DNA at specific sequences (called restriction sites)

Question 3

DNA ligase

Answer 3

• making the insertion permanent
• an enzyme that will join DNA fragments together
• will make the phosphodiester bonds occur quicker

Question 4

plasmid

Answer 4

• small, ciruclar
• only 3-5kb large, can be up to 10 for the insert
• have many restriction sites
• not very likely to be attacked by the host

Question 5

ori

Answer 5

• origin of replication
• where the replication begings

Question 6

copy number control

Answer 6

• how much the plasmid will copy when under selective pressure
• can be high or low

Question 7

selectable marker

Answer 7

• able to dictate that the cells only containing the plasmid will survive in selective pressure
• normally antibiotic resisitance

Question 8

promoter

Answer 8

• initaite transciption of inserted sequences
• don’t need to insert plasmid but need it to express the DNA

Question 9

reporter genes

Answer 9

• express proteins that are easily detectable

Question 10

blunt ends

Answer 10

• clean cut in the DNA
• all bases are still connected to another base, all H bonds are already

Question 11

sticky ends

Answer 11

• messy cut to the dna
• bases are not all connecting, leaving opportunities for attachment of plasmids and such
• have readily avalibaile H bonds
• able to bond to another strand more easily

Question 12

transformation

Answer 12

• the uptake of naked DNA (usually a plasmid)
• the cells that take up this DNA are called competent cells
• some cells are naturally competent, like E. coli, but some or not but they can become competent

Question 13

heat shock

Answer 13

• growing cell to log phase
• washing in ice-cold CaCl2
• heat shock to destabilize the cell membranes
• allow to grow in growth medium
• place on selective medium to produce chemically competent cells

Question 14

electroporation

Answer 14

• grow to log phase
• collect with centrifugation
• wash and resuspend with water and glycerol
• add DNA and cell to cuvette
• zap with short voltage pulses
• allow to grow in growth medium
• plate on selective medium to produce electrocompetent cells

Question 15

bacteriophage lambda

Answer 15

• viruses that infect bacteria
• It has a common structure of a head and tail with most having tail fibres
• The genome is about 5000bp
• tightly wound into the capsid

Question 16

cosmids

Answer 16

• plasmid with a packagin cos site that can only apckge in vitra environments
• will circularize to form a plasmid following a phage infection