BIOL 4003; FINAL EXAM questions
well answered
What is a healthy cell in terms of DNA damage and rate of repair? - ANS ✔✔rate of DNA
damage = rate of repair
What is a diseased cell in terms of DNA damage and rate of repair? - ANS ✔✔rate of DNA
damage > rate of repair
Damage to DNA that is not correctly repaired leads to _________ in DNA sequences that can
alter the characteristics of organisms. - ANS ✔✔mutations
DNA damage - ANS ✔✔a physical or chemical defect in the structure of DNA that can often be
fixed by repair mechanisms in cells
ex: base loss, alteration, mismatch, or crosslink, strand break
mutation - ANS ✔✔changes in the base sequence of both strands of DNA that cannot be
repaired; able to be transmitted successive generations
germ-line mutations - ANS ✔✔occur in gametes, passed onto offspring
somatic mutations - ANS ✔✔occur in all cell types except gametes, not passed onto offspring
DNA repair - ANS ✔✔direct reversal or multi-step pathways; accurate leads to wt DNA
sequence, inaccurate leads to mutant DNA sequence
,Mutant DNA sequences can be ______, _______, or ________. - ANS ✔✔beneficial, harmful, or
neutral
Types of DNA mutations - ANS ✔✔point mutations, insertion/deletion (indel), repeat
expansions, DNA strand break
transition substitution - ANS ✔✔purine to purine or pyrimidine to pyrimidine
transversion substitution - ANS ✔✔purine to pyrimidine or
pyrimidine to purine
consequences of point mutations - ANS ✔✔synonymous, nonsynonymous: missense
(conservative or nonconservative), and nonsense mutations; affect protein binding sites
synonymous/silent mutations - ANS ✔✔altered codon specifies the same aa as wt
conservative missense mutations - ANS ✔✔changes the sequence of a codon to one that codes
for a different, but functionally similar amino acid
nonconservative missense mutations - ANS ✔✔changes the sequence of a codon to one that
codes for a chemically different amino acid
nonsense mutations - ANS ✔✔altered codon signals chain termination
nonsynonymous mutation - ANS ✔✔changes aa
nonsense suppressor mutation - ANS ✔✔a mutation in the anti-codon of a tRNA carrying an
amino acid to a STOP codon; continues translation despite stop
,Effects of mutations can be assayed by _______ of DNA, RNA, or Proteins. - ANS ✔✔Gel
electrophoresis
Southern blotting measures _____. - ANS ✔✔DNA
Northern blotting measures _____. - ANS ✔✔RNA
Western blotting measures _____. - ANS ✔✔Protein
Ras G12V mutation - ANS ✔✔prevents de-activation of Ras by removing phosphate from GTP;
can lead to abnormal promotion of cell growth and cancer
consequences of point mutations outside a gene - ANS ✔✔1. binding of transcriptional
regulators
2. processing of pre-mRNA intron splicing
3. binding of miRNAs
base insertion/deletion (indel) mutations - ANS ✔✔insertion or deletion of a bp; cause
frameshift mutations and occur during DNA replication
frameshift mutation - ANS ✔✔mutation that shifts the "reading" frame of the genetic message
by inserting or deleting a nucleotide
Repeat expansions - ANS ✔✔increase in the number of copies of short tandem repeats; due to
replication slippage
, ex: Fragile-X syndrome caused by repeats hindering transcription of FMR gene, ALS (C9orf72
intron) stops transcription, Huntington's disease protein coding region (abnormal # of
glutamines)
The Luria and Delbruck Fluctuation Test - ANS ✔✔demonstrated that mutations are not
adaptive but occur spontaneously
replica plating - ANS ✔✔A method of identifying bacterial colonies that have certain mutations
by transferring cells from each colony on a master plate to a second (replica) plate and
observing their growth when exposed to different conditions.
spontaneous mutation - ANS ✔✔a natural and random mutation that occurs in the absence of a
mutagen or selective force, usually due to errors in the normal functioning of cellular processes
possible causes of spontaneous mutations - ANS ✔✔errors in DNA replication, spontaneous
lesions or alteration of bps, and transposable genetic elements
Errors in DNA replication - ANS ✔✔- different forms of nucleotides (tautomeric or ionized) =
mismatched base pairs
- replication slippage (indel or repeat mutations)
tautomeric base pairs - ANS ✔✔affects the nitrogenuous bases of dNTPs and can turn them into
their imino or enol forms
ionized base pairs - ANS ✔✔charges on the bases are changed
spontaneous lesions - ANS ✔✔arise from damage to DNA from water or reactive oxygen species
in cellular environment: depurination and deamination
well answered
What is a healthy cell in terms of DNA damage and rate of repair? - ANS ✔✔rate of DNA
damage = rate of repair
What is a diseased cell in terms of DNA damage and rate of repair? - ANS ✔✔rate of DNA
damage > rate of repair
Damage to DNA that is not correctly repaired leads to _________ in DNA sequences that can
alter the characteristics of organisms. - ANS ✔✔mutations
DNA damage - ANS ✔✔a physical or chemical defect in the structure of DNA that can often be
fixed by repair mechanisms in cells
ex: base loss, alteration, mismatch, or crosslink, strand break
mutation - ANS ✔✔changes in the base sequence of both strands of DNA that cannot be
repaired; able to be transmitted successive generations
germ-line mutations - ANS ✔✔occur in gametes, passed onto offspring
somatic mutations - ANS ✔✔occur in all cell types except gametes, not passed onto offspring
DNA repair - ANS ✔✔direct reversal or multi-step pathways; accurate leads to wt DNA
sequence, inaccurate leads to mutant DNA sequence
,Mutant DNA sequences can be ______, _______, or ________. - ANS ✔✔beneficial, harmful, or
neutral
Types of DNA mutations - ANS ✔✔point mutations, insertion/deletion (indel), repeat
expansions, DNA strand break
transition substitution - ANS ✔✔purine to purine or pyrimidine to pyrimidine
transversion substitution - ANS ✔✔purine to pyrimidine or
pyrimidine to purine
consequences of point mutations - ANS ✔✔synonymous, nonsynonymous: missense
(conservative or nonconservative), and nonsense mutations; affect protein binding sites
synonymous/silent mutations - ANS ✔✔altered codon specifies the same aa as wt
conservative missense mutations - ANS ✔✔changes the sequence of a codon to one that codes
for a different, but functionally similar amino acid
nonconservative missense mutations - ANS ✔✔changes the sequence of a codon to one that
codes for a chemically different amino acid
nonsense mutations - ANS ✔✔altered codon signals chain termination
nonsynonymous mutation - ANS ✔✔changes aa
nonsense suppressor mutation - ANS ✔✔a mutation in the anti-codon of a tRNA carrying an
amino acid to a STOP codon; continues translation despite stop
,Effects of mutations can be assayed by _______ of DNA, RNA, or Proteins. - ANS ✔✔Gel
electrophoresis
Southern blotting measures _____. - ANS ✔✔DNA
Northern blotting measures _____. - ANS ✔✔RNA
Western blotting measures _____. - ANS ✔✔Protein
Ras G12V mutation - ANS ✔✔prevents de-activation of Ras by removing phosphate from GTP;
can lead to abnormal promotion of cell growth and cancer
consequences of point mutations outside a gene - ANS ✔✔1. binding of transcriptional
regulators
2. processing of pre-mRNA intron splicing
3. binding of miRNAs
base insertion/deletion (indel) mutations - ANS ✔✔insertion or deletion of a bp; cause
frameshift mutations and occur during DNA replication
frameshift mutation - ANS ✔✔mutation that shifts the "reading" frame of the genetic message
by inserting or deleting a nucleotide
Repeat expansions - ANS ✔✔increase in the number of copies of short tandem repeats; due to
replication slippage
, ex: Fragile-X syndrome caused by repeats hindering transcription of FMR gene, ALS (C9orf72
intron) stops transcription, Huntington's disease protein coding region (abnormal # of
glutamines)
The Luria and Delbruck Fluctuation Test - ANS ✔✔demonstrated that mutations are not
adaptive but occur spontaneously
replica plating - ANS ✔✔A method of identifying bacterial colonies that have certain mutations
by transferring cells from each colony on a master plate to a second (replica) plate and
observing their growth when exposed to different conditions.
spontaneous mutation - ANS ✔✔a natural and random mutation that occurs in the absence of a
mutagen or selective force, usually due to errors in the normal functioning of cellular processes
possible causes of spontaneous mutations - ANS ✔✔errors in DNA replication, spontaneous
lesions or alteration of bps, and transposable genetic elements
Errors in DNA replication - ANS ✔✔- different forms of nucleotides (tautomeric or ionized) =
mismatched base pairs
- replication slippage (indel or repeat mutations)
tautomeric base pairs - ANS ✔✔affects the nitrogenuous bases of dNTPs and can turn them into
their imino or enol forms
ionized base pairs - ANS ✔✔charges on the bases are changed
spontaneous lesions - ANS ✔✔arise from damage to DNA from water or reactive oxygen species
in cellular environment: depurination and deamination
