Molecular Genetics Flashcards
(17 cards)
When was the first use of restriction enzymes in recombinant DNA
1971
What are the 2 types of cuts of DNA when using restriction enzymes
- blunt ends
- sticky ends
What do methyltransferases (enzymes) do
Catalysed the transfer of a methyl group to DNA bases - used to block restriction sites
What do nucleases do
Enzymes that cleave randomly nucleic acids
Deoxyribonucleases = cleave DNA
Either endonucleases = cut inside sequence or exonucleases = cut from extremities
Ribonucleases = cut RNA
What do DNA ligases do
Catalysed the formation of a covalent phosphodiester bond between 5’ phosphate and 3’ hydroxyl of another DNA fragment
What do DNA polymerases do
Copy a DNA strand into another DNA strand
What are the 3 main types of DNA polymerases in bacteria
DNA pol. I - main enzyme for DNA replication
DNA pol. II - involved in DNA repair
DNA pol. III - involved in DNA replication
What is processivity
the number of nucleotides added to the new strand per second
What is fidelity
the rate of errors
What is
What do RNA polymerases do
Transcribe single stranded DNA into RNA
What do reverse transcriptases do
Transcribe single stranded RNA into single stranded complementary DNA (cDNA)
What are vectors
Used as carriers of foreign DNA into host cells
What are 5 types of vectors
- plasmids
- phagemids
- cosmids
- bacterial artificial chromosome (BAC)
- yeast artificial chromosome (YAC)
What are molecular probes used for
For detection of DNA / RNA targets present in complex samples
What are oligonucleotides used for
Single strand oligos = primers for DNA + RNA amplification
Double stranded oligos = adapters that are ligated to DNA fragments to facilitate cloning
