QBM exam | 100 Questions Solved with
Verified Correct Answers | Latest Update
2024-2025
Three samples are digested with EcoRI and run out on a gel as shown. What can be done to
prevent the star activity seen in Lane 4? - ANSWER All (Maintain a lower DNA enzyme
ratio, adjust the pH of the buffer to ensure optimal conditions for the restriction enzyme,
remove glycerol and ethylene glycol from the buffer, remove glycerol and ethylene glycol
from the buffer, use a high-fidelity enzyme to reduce star activity)
Based on the following restriction digests with restriction enzymes A and B, what could be a
possible restriction map that fits this data? The lines in the answers represent a single piece
of DNA, and the As and Bs represent cut sites. - ANSWER NOT AABB
ORAB
ORAAAB
TRY AAAB
A circular piece of DNA is cut with HpaII and generates 3 fragments. How many HpaII cut
sites were present on the circular DNA? - ANSWER 3
Which lane below represents a digestion with PstI and XbaI? - ANSWER Lane 5
DNA polymerases have ______ downstream exonuclease activity for primer removal, and
______ proofreading exonuclease activity. - ANSWER 5'→3' ; 3'→5'
, The Klenow fragment is a variation of DNA polymerase I with the ________ domain removed to
prevent ________. - ANSWER 5'→3' exonuclease ; primer removal
Which of the following is true about creating blunt ends? - ANSWER T4 DNA polymerase
can chew back 3' overhangs and fill in 5' overhangs.
Two pieces of DNA can be joined together by - ANSWER DNA ligase
In TA cloning, the insert and plasmid can be ligated together using - ANSWER NOT reverse
transcriptase.
NOT primase
The process of introducing a plasmid into a bacterial cell is called - ANSWER transformation
What is unique about the strains of E. coli used in the laboratory for protein expression, when
compared to wild type E. coli? - ANSWER Laboratory E. coli lacks proteases and restriction
enzymes
Adding CaCl2 to E. coli cells - ANSWER disrupts the E. coli membrane to allow DNA to enter
the cells.
Which of the following techniques can be used to introduce foreign DNA into E. coli? - ANSWER
ALL (In vitro packaging, CaCl2 treatment, An electric current)
Why are cloning vectors preferred to expression vectors for initial cloning of a gene? - ANSWER
ALL (Cloning vectors are usually smaller, so allow for a more efficient transformation,
Expression vectors usually have fewer restriction enzyme options in the MCS, Cloning vectors
replicate easier and produce high copy numbers.)
Verified Correct Answers | Latest Update
2024-2025
Three samples are digested with EcoRI and run out on a gel as shown. What can be done to
prevent the star activity seen in Lane 4? - ANSWER All (Maintain a lower DNA enzyme
ratio, adjust the pH of the buffer to ensure optimal conditions for the restriction enzyme,
remove glycerol and ethylene glycol from the buffer, remove glycerol and ethylene glycol
from the buffer, use a high-fidelity enzyme to reduce star activity)
Based on the following restriction digests with restriction enzymes A and B, what could be a
possible restriction map that fits this data? The lines in the answers represent a single piece
of DNA, and the As and Bs represent cut sites. - ANSWER NOT AABB
ORAB
ORAAAB
TRY AAAB
A circular piece of DNA is cut with HpaII and generates 3 fragments. How many HpaII cut
sites were present on the circular DNA? - ANSWER 3
Which lane below represents a digestion with PstI and XbaI? - ANSWER Lane 5
DNA polymerases have ______ downstream exonuclease activity for primer removal, and
______ proofreading exonuclease activity. - ANSWER 5'→3' ; 3'→5'
, The Klenow fragment is a variation of DNA polymerase I with the ________ domain removed to
prevent ________. - ANSWER 5'→3' exonuclease ; primer removal
Which of the following is true about creating blunt ends? - ANSWER T4 DNA polymerase
can chew back 3' overhangs and fill in 5' overhangs.
Two pieces of DNA can be joined together by - ANSWER DNA ligase
In TA cloning, the insert and plasmid can be ligated together using - ANSWER NOT reverse
transcriptase.
NOT primase
The process of introducing a plasmid into a bacterial cell is called - ANSWER transformation
What is unique about the strains of E. coli used in the laboratory for protein expression, when
compared to wild type E. coli? - ANSWER Laboratory E. coli lacks proteases and restriction
enzymes
Adding CaCl2 to E. coli cells - ANSWER disrupts the E. coli membrane to allow DNA to enter
the cells.
Which of the following techniques can be used to introduce foreign DNA into E. coli? - ANSWER
ALL (In vitro packaging, CaCl2 treatment, An electric current)
Why are cloning vectors preferred to expression vectors for initial cloning of a gene? - ANSWER
ALL (Cloning vectors are usually smaller, so allow for a more efficient transformation,
Expression vectors usually have fewer restriction enzyme options in the MCS, Cloning vectors
replicate easier and produce high copy numbers.)
