Enzymes And Restriction Mapping

Question 1

What are the uses of genetic engineering?

Answer 1

Transgenic organisms and recombinant proteins

Question 2

Give some examples of transgenic organisms

Answer 2

Disease models and improved agricultural yields

Question 3

Give some examples of recombinant proteins

Answer 3

Insulin, interferon and G-CSF

Question 4

What does G-CSF do?

Answer 4

Promote formation of bone marrow in cancer patients

Question 5

What do nucleases do?

Answer 5

Degrade nuclear acids by hydrolysing phosphodiesterase bonds

Question 6

What degrades RNA?

Answer 6

Ribonuclease

Question 7

What degrades DNA?

Answer 7

Deoxyribonuclease

Question 8

What do restriction endonucleases do?

Answer 8

Limits the transfer of nucleic acids from infecting phages into bacteria

Question 9

How do restriction endonucleases work?

Answer 9

Recognising a specific sequence and cutting it.

Question 10

What is special about restriction endonuclease recognition sites?

Answer 10

4-8 bases in length and palindromic

Question 11

What does DNA ligase do?

Answer 11

Joins DNA molecules from different sources to form recombinant DNA

Question 12

What can SNPs do?

Answer 12

Create/ destroy restriction enzyme sites

Question 13

What do you use the enzyme Dde1 to do?

Answer 13

Cleave when doing PCR for sickle cell anaemia testing

Question 14

What is a restriction map?

Answer 14

A crude way of mapping an unknown molecule

Question 15

What is a restriction map useful for?

Answer 15

Describing plasmids

Question 16

How do you get a restriction map?

Answer 16

By performing gel electrophoresis

Question 17

What are the main uses of DNA polymerases?

Answer 17

PCR amplification, generation of probes and blunt- ending of DNA

Question 18

What are phosphatases used for?

Answer 18

Preventing cleaved plasmids from resealing

Question 19

How do phosphatases work?

Answer 19

Hydrolysing a phosphate group off its substrate

Question 20

How do polynucleotide kinases work?

Answer 20

Adds phosphate to the 5’ hydroxyl group of DNA or RNA

Question 21

What are polynucleotide kinases used for?

Answer 21

To sensitively label DNA so that it can be traced using radioactively or fluorescently labelled ATP

Question 22

What is a probe?

Answer 22

A fragment of single stranded DNA or RNA that is complementary to the gene of interest

Question 23

How long are probes generally?

Answer 23

20-1000 bases

Question 24

How does reverse transcriptase work?

Answer 24

RNA dependant DNA polymerase that is isolated from RNA containing retroviruses. Then synthesises a DNA molecule that is complementary to an mRNA template using dNTPs

Question 25

What are the three types of primers for reverse transcription?

Answer 25

Random primers, oligoprimers and gene specific primers

Question 26

What is good about using random primers for reverse transcription?

Answer 26

Complementary DNA up to 700 bases but will cover the length of all the RNA molecules

Question 27

What is good about using oligoprimers for reverse transcription?

Answer 27

They're useful for cloning cDNAs and their libraries but some might not be full length