Mutations, Recombinations, and DNA Repair

Question 1

result of changes in the mRNA codon nucleotide sequence o alter the genetic information that is passed on during transcription

Answer 1

Mutation

Question 2

Shift the reading frame of the entire DNA chain after the mutation. It includes deletion mutation and insertion mutation

Answer 2

Frame shift mutation

Question 3

to occur when DNA polymerase synthesizes new DNA slips on the template DNA strand, effectively missing a nucleotide

Answer 3

Deletion mutation

Question 4

Acridine intercalates between adjacent DNA nitrogen bases and gets read by RNA polymerase causing the addition of extra bases into the new mRNA

Answer 4

Insertion mutation

Question 5

The addition or removal of one or more base pairs leads to insertion or deletion mutations, the loss or addition of a single
nucleotide causes all the
subsequent three- letter codons to be changed.

Answer 5

Insertion and deletion

Question 6

Arise when a base pairs with an inappropriate partner during DNA replication

Answer 6

Point mutations

Question 7

It is where one purine (or pyrimidine) is replaced by PURINE or vice versa

Answer 7

Transition

Question 8

It is where a purine is substituted for a pyrimidine or vice versa

Answer 8

Transversion

Question 9

Change codon to another for the same amino acid, so has no effect

Answer 9

Silent mutation

Question 10

Change codon to a stop codon and terminates synthesis

Answer 10

Nonsense mutation

Question 11

Changes codon to another codon for a different amino acid. If the new amino acid is similar to the old one, the synthesized protein might function

Answer 11

Missense mutation

Question 12

DNA encodes the cell genome and is therefore a permanent
copy of a structure necessary
for the correct functioning of a cell. Changes to the structure of DNA can cause mutations and genomic instability, leading to cancer. Damage to DNA is caused by the incorporation of incorrect nucleotide bases during DNA replication and the chemical changes caused by spontaneous mutation or
exposure to environmental
factors such as radiation.

Answer 12

DNA repair for mutation

Question 13

can be activated by
absorbing energy from near-UV to blue light, Because it requires the presence of light

Answer 13

Photoreactivating enzyme or photolyase

Question 14

a mechanism of repair that does not require a template and is applied to two main types of damage. UV light induces the formation of pyrimidine dimers
which can distort the DNA chain structure, blocking transcription beyond the area of damage.

Answer 14

Direct reversal of DNA repair

Question 15

is the general
mechanism by which repairs
are made when one of the
double helix strands is
damaged. The non-defective
strand is used as a template with the damaged DNA on the other strand removed and replaced by the synthesis of new nucleotides.

Answer 15

DNA repair by excision

Question 16

involves the recognition and removal of a single damaged base

Answer 16

Base-excision repair

Question 17

used to repair the formation of pyrimidine dimers from UV light within humans

Answer 17

Nucleotide excision repair

Question 18

The repair of damage to both DNA strands is particularly important in maintaining genomic integrity. There are
two main mechanisms for repairing double strand breaks: homologous
recombination and classical
nonhomologous end joining.

Answer 18

Mismatch repair

Question 19

involves the exchange of nucleotide sequences to repair damaged bases on both strands of DNA through the utilization of a sister chromatid

Answer 19

Homologous recombination

Question 20

Studies have also found that
double strand breaks can be
repaired through alternative mechanisms such as single-
stranded annealing and alternative joining during certain conditions. These mechanisms are mutagenic and can lead to a
loss in genetic information.

Answer 20

Single strand annealing