Nucleic Acids and DNA Cloning Flashcards
What are the three types DNA manipulating enzymes?
Nucleases, ligases and modifying enzymes
What do nucleases do?
Break down the phosphodiester bonds in DNA
What are nucleases?
Catalysed metal ions
What is the difference between exonucleases and endonucleases?
Exonucleases work from the ends of the amino acid chain whereas endonucleases work form the middle of the amino acid chain.
What do restriction enzymes do?
Cut the double stranded DNA
What is a ‘sticky’ end?
Cleaved DNA with an overhanging 5’ end
What is a ‘blunt’ end?
Cleaved DNA where both strands have an equal number of base pairs.
What are the 4 modifying enzymes and what do they do?
alkaline phosphatase (removes phosphate ends from DNA), polynucleotide kinase (transfers gamma phosphate from ATP to 5’ end), terminal deoxynucleotidyl transferase (adds nucleotides to 3’ end), klenow fragment (lacks 5’-3’ exonuclease activity, but has 3’-5’ exonuclease and 5’-3’ polymerase activity)
What are the three requirements of recombinant DNA?
vectors to propigate DNA (plasmids, viruses and derivatives), scissors to cut DNA (restriction enzymes) and glue to stick DNA pieces together (DNA ligase).
What are vectors?
Small, autonomously replicating DNA molecules.
What are plasmids?
Circular, supercoiled DNA molecules in bacterial cells
What are episomes?
plasmids that can integrate into bacterial chromosomes
What is transformation?
Taking DNA into bacterial cells
What does exonuclease III do?
Create single stranded DNA from double stranded
What does S1 nuclease do?
Cleaves, specifically, single stranded nucleases
