DNA mutation and repair UPDATED
ACTUAL Exam Questions and CORRECT
Answers
nature of mutations - CORRECT ANSWER - -generally occur random and spontaneously
-lederberg experiment
-can be good, bad, or neutral
mutations result from - CORRECT ANSWER - 1. DNA replication errors
-nucleotide; base substitutions
2. un-repaired DNA damage
-endogenous (ex: free radicals)
-exogenous (found in environment; chemicals, radiation)
high fidelity DNA synthesis - CORRECT ANSWER - -beneficial for maintaining genetic
information over generations and for avoiding mutations
-mutations can still occur
low fidelity DNA synthesis - CORRECT ANSWER - -beneficial for the evolution of species
bc generates diversity for increased survival when subjected to changing environments
mutation rate - CORRECT ANSWER - -prokaryotes add about 1000 nucleotides per second
- 1 error per every 100,000 nucleotides
-99% of these mistakes are corrected by proofreading during replication
-most of the rest are fixed after replication by mismatch repair
-actually about 1 mutation per 10^9 nucleotides (billion)
, DNA proofreading - CORRECT ANSWER - DNA polymerase removes incorrect nucleotides
and replaces it with the correct one
Most mutations in DNA result from: - CORRECT ANSWER - DNA replication errors
How does DNA Pol III fix an error during proofreading: - CORRECT ANSWER - -with its 3'
to 5' exonuclease activity
rate of mutation per base pair per round of replication - CORRECT ANSWER - -HIV virus: 1
nucleotide in every 100K
-bacteria: 1 nucleotide in every 1 billion
-humans: 1 nucleotide in every 10 billion
Which of the following is incorrect regarding the rate of mutation per base pair per round of
replication:
A
the rate for humans is low because their genome is so large
B
RNA viruses have a high mutation rate because reverse transcriptase is a low-fidelity copying
enzyme
C
there is an unknown organism plotted at 10-6. This organism has 1 mutation per every 1 million
nucleotides
D
the rate for bacteria is higher than humans because humans have higher fidelity DNA mutation
correction machinery - CORRECT ANSWER - the rate for humans is low because their
genome is so large
rate of mutation per genome per generation - CORRECT ANSWER - -dependent on the size
of the genome and the number of cell divisions per generation
ACTUAL Exam Questions and CORRECT
Answers
nature of mutations - CORRECT ANSWER - -generally occur random and spontaneously
-lederberg experiment
-can be good, bad, or neutral
mutations result from - CORRECT ANSWER - 1. DNA replication errors
-nucleotide; base substitutions
2. un-repaired DNA damage
-endogenous (ex: free radicals)
-exogenous (found in environment; chemicals, radiation)
high fidelity DNA synthesis - CORRECT ANSWER - -beneficial for maintaining genetic
information over generations and for avoiding mutations
-mutations can still occur
low fidelity DNA synthesis - CORRECT ANSWER - -beneficial for the evolution of species
bc generates diversity for increased survival when subjected to changing environments
mutation rate - CORRECT ANSWER - -prokaryotes add about 1000 nucleotides per second
- 1 error per every 100,000 nucleotides
-99% of these mistakes are corrected by proofreading during replication
-most of the rest are fixed after replication by mismatch repair
-actually about 1 mutation per 10^9 nucleotides (billion)
, DNA proofreading - CORRECT ANSWER - DNA polymerase removes incorrect nucleotides
and replaces it with the correct one
Most mutations in DNA result from: - CORRECT ANSWER - DNA replication errors
How does DNA Pol III fix an error during proofreading: - CORRECT ANSWER - -with its 3'
to 5' exonuclease activity
rate of mutation per base pair per round of replication - CORRECT ANSWER - -HIV virus: 1
nucleotide in every 100K
-bacteria: 1 nucleotide in every 1 billion
-humans: 1 nucleotide in every 10 billion
Which of the following is incorrect regarding the rate of mutation per base pair per round of
replication:
A
the rate for humans is low because their genome is so large
B
RNA viruses have a high mutation rate because reverse transcriptase is a low-fidelity copying
enzyme
C
there is an unknown organism plotted at 10-6. This organism has 1 mutation per every 1 million
nucleotides
D
the rate for bacteria is higher than humans because humans have higher fidelity DNA mutation
correction machinery - CORRECT ANSWER - the rate for humans is low because their
genome is so large
rate of mutation per genome per generation - CORRECT ANSWER - -dependent on the size
of the genome and the number of cell divisions per generation
