Chapter 4 Flashcards
Remove nucleotides one at a time from the end of a DNA molecule
Exonucleases
Cut internal phosphodiester bonds within a DNA molecule
Endonucleases
An example of an exonuclease that removes nucleotides from both strands of a double-stranded DNA molecule. Longer exposure to enzyme results in shorter DNA fragments.
Bal31
In contrast, this enzyme degrades only one strand, leaving single-stranded DNA.
E. coli Exonuclease III
Cuts only single strands.
S1 Endonuclease
Exonucleases enzyme Cuts both single and double-stranded DNA. It’s non-specific, attacking any internal bond, leading to a mix of mononucleotides and short oligonucleotides.
Deoxyribonuclease I (DNase I)
Specialized enzymes that cleave double-stranded DNA only at specific sites.
Restriction Endonucleases
Resistant to heat, making it ideal for PCR testing
Taq DNA Polymerase
DNA enzyme repairs single-stranded breaks (discontinuities) in double-stranded DNA and essential ability in constructing recombinant DNA molecules.
Ligases
enzymes that synthesize new DNA strands based on existing DNA or RNA templates.
Polymerases
Where Taq DNA Polymerase extract from
Thermus aquaticus
A process Synthesizes DNA complementary to RNA
Reverse Transcriptase
In genetic engineering, certain enzymes are used to modify DNA molecules by specifically adding or removing chemical groups.
DNA modifying enzymes
Enzyme function Removes the phosphate group from the 5′ end of a DNA molecule.
Alkaline Phosphatase
Enzymefunction Adds phosphate groups to free 5′ ends of DNA.
Polynucleotide Kinase
