Enzymes in Molecular Biology Flashcards
What do polymerases do
They create polymers of nucleic acids such as DNA & RNA
What kind of rxn is involved in forming a phosphodiester bond
Condensation rxn
Examples of DNA polymerases in vivo
- DNA replication
- DNA repair
Example of DNA polymerase in vitro
PCR (polymerase chain rxn)
Example of RNA polymerase in vivo
Transcription
What are nucleases
Enzymes that cleave the phosphodiester bonds between nucleotide subunits of nucleic acids
How do endonucleases work
Endonucleases break the DNA internally (make internal cuts)
How do exonucleases work
Exonucleases cut and remove nucleotides from the ends of DNA strand.
They work either in a 5’-3’ direction or a 3’-5’ direction
Examples of nucleases in vivo
- DNA repair: clips out damaged DNA
- Cell death: 1st step in apoptosis is nucleases breaking down DNA
Example of nuclease in vitro
Nucleic acid digests
What do DNA ligases do
DNA ligases join DNA strands together by catalysing the formation of a phosphodiester bond.
Can join one end of a DNA molecule to the other end of the same DNA molecule or can join two DNA molecules together.
Examples of ligases in vivo
- DNA replication
- DNA repair
Example of ligases in vitro
Cloning