Enzymes Flashcards
(12 cards)
What does DNA polymerase do?
Joins DNA nucleotides together to form the sugar phosphate backbone of a new DNA strand
When and where is DNA polymerase used?
DNA replication
PCR
What does RNA polymerase do?
Joins RNA nucleotides together to form the sugar phosphate backbone of a new (pre)mRNA strand
When/where is RNA polymerase used?
Transcription
What does DNA helicase do?
Breaks H bonds between complementary base pairs to separate DNA strands
When/where is DNA helicase used?
DNA replication
(Transcription)
What does DNA ligase do?
Joins complementary sticky ends (of plasmid and ‘gene’)
When/where is DNA ligase used?
Genetic engineering- formation of recombinant DNA/ recombinant plasmid
What does restriction endonuclease do?
Cuts DNA at specific base sequence
(For recombinant DNA -same restriction enzyme cuts DNA and plasmid to give complementary ends)
(For genetic fingerprints - cuts at specific VNTRs)
When/where is restriction endonuclease used?
Genetic engineering:
To isolate DNA and cut plasmid in production of recombinant plasmid
To create DNA fragments (of different sizes of electrophoresis- used in genetic fingerprinting, sequencing, screening etc)
What does reverse transcriptase do?
Makes cDNA from mRNA (extracted from a cell which produces mRNA in large quantities)
When/ where is reverse transcriptase used?
