Module 3 Error Correction in DNA Replication

Question 1

is an error that occurs from replication

Answer 1

replication error

Question 2

a mistake made in the base-pairing. A nucleotide
bearing guanine (G) was added as the pair of T. Correction involved
replacing the excised G with an A.

Answer 2

mispairing / addition of a nucleotide with an incorrect base

Question 3

_____ is when a nucleotide is added between nucleotides and _____ is when there is a missing nucleotide
in the sequence.

Answer 3

insertion ; deletion

Question 4

DNA strand can slip during replication and
can cause addition or deletion of a nucleotide.

Answer 4

Strand slippage

Question 5

DNA damage

Answer 5

Chemical damage
Damage caused by radiation
Damage due to attack by water

Question 6

is important for removing damaged bases that
could otherwise cause mutations by mispairing or lead to breaks in DNA
during replication

is initiated by DNA glycosylases, which
recognize and remove specific damaged or inappropriate bases, forming
AP sites. AP stands for apurinic/apyrimidinic (missing purine or
pyrimidine).

Answer 6

Base Excision Repair (BER)

Question 7

repairs damaged caused by pyrimidine dimer.

is an excision nuclease that makes a cut a few nucleotides upstream (to 5’ end), thus making the removal of a longer segment possible.

Answer 7

nucleotide excision repair

Question 8

varies from base-pair excision in that the
enzymes will recognize and remove “short patches” of DNA that are
damaged. These short patches of damage arise from bulky lesions such
as thymine dimers.

Answer 8

Short-patch excision repair

Question 9

follows the
same mechanism as the short-patch type
but involves a longer segment of DNA

Answer 9

Long-patch excision repair

Question 10

is able to identify mismatch errors because such damage leads to a small distortion in the DNA backbone.

Answer 10

mismatch repair