BIOLOGY EXAM REVIEW 6512 WITH CORRECT
ANSWERS 2025
exonuclease - CORRECT ANSWER -cleave a complement DNA strand from a terminus
requires a free -OH
must work on either single-stranded or dsDNA
used for proofreading during DNA synthesis
used to decompose foreign DNA
endonuclease - CORRECT ANSWER -cleave a phosphodiester backbone at internal DNA sequences
usually yields stick ends
results in 3'-OH and 5'-phosphate
hydrolytic reaction...H2O adds into the phosphate
some cleave randomly (e.g. DNase I) and others have high specificity (e.g. EcoR1)
restriction enzymes - CORRECT ANSWER -
typically recognize and cleave inverted repeats of specific DNA sequences
look for inverted repeats
produces kink in DNA
ethidium bromide - CORRECT ANSWER -binds to 2 adjacent G-G pairs
orange fluorescent
fluorescence increases 20-fold upon DNA binding
mutagen...handle with care
DNA ligase - CORRECT ANSWER -synthesizes phophodiester bonds between 3-=OH and 5'-phosphate
requires dsDNA
ANSWERS 2025
exonuclease - CORRECT ANSWER -cleave a complement DNA strand from a terminus
requires a free -OH
must work on either single-stranded or dsDNA
used for proofreading during DNA synthesis
used to decompose foreign DNA
endonuclease - CORRECT ANSWER -cleave a phosphodiester backbone at internal DNA sequences
usually yields stick ends
results in 3'-OH and 5'-phosphate
hydrolytic reaction...H2O adds into the phosphate
some cleave randomly (e.g. DNase I) and others have high specificity (e.g. EcoR1)
restriction enzymes - CORRECT ANSWER -
typically recognize and cleave inverted repeats of specific DNA sequences
look for inverted repeats
produces kink in DNA
ethidium bromide - CORRECT ANSWER -binds to 2 adjacent G-G pairs
orange fluorescent
fluorescence increases 20-fold upon DNA binding
mutagen...handle with care
DNA ligase - CORRECT ANSWER -synthesizes phophodiester bonds between 3-=OH and 5'-phosphate
requires dsDNA
