BCH5413 EXAM 4 UPDATED ACTUAL
Exam Questions and CORRECT Answers
Central Dogma of Molecular Biology - CORRECT ANSWER - DNA -> RNA -> Protein
endogenous factors that cause DNA damage - CORRECT ANSWER - error in replication
bully addict formation
oxidation
alkylation
hydrolysis
exogenous factors that cause DNA damage - CORRECT ANSWER - UV, chemicals, x-
rays, ionizing radiation
emethanesulfate (EMS) - CORRECT ANSWER - DNA alkylation medicine for cancer
GC base pairing when guanine is exposed to EMS - CORRECT ANSWER - guanine to
06-ethylguanine and bins to thymine
EMS as a cancer treatment - CORRECT ANSWER - interferes with transcriptional and
DNA replication
alkylation event that does not change base pairing - CORRECT ANSWER - attacks
phosphodiester bond
endogenous sources of oxidative stress - CORRECT ANSWER - respiration, stress
exogenous sources of oxidative stress - CORRECT ANSWER - smoking, alcohol,
pollution, water, pesticides, medications, food (meat)
,Result of oxidative damage - CORRECT ANSWER - guanine oxidation
-biomarker of oxidative stress
-mutagenic
Hoogsteen base pairing - CORRECT ANSWER - - Occurs when one base is in the syn
conformation.
-G-A base pair
UV-A damage - CORRECT ANSWER - free radicals
UV-B damage - CORRECT ANSWER - pyrimidine dimers
Gamma and X-ray damage - CORRECT ANSWER - ss or ds DNA break, altered bases
(oxidized)
ionizing radiation - CORRECT ANSWER - radiation w/enough energy to free electrons
from atoms forming ions, may cause cancer (ex. gamma, X-rays, UV). Ionizes molecules around
DNA ( water) to form highly reactive free radicals that attack DNA backbone
oxidative stress, alkylating agents effect on DNA - CORRECT ANSWER - Base
modification: alkylation, methylation, oxidation
polycyclic aromatic hydrocarbons effect on DNA - CORRECT ANSWER - adduct
intercalation between bases
spontaneous events effect on DNA - CORRECT ANSWER - depyrimidation, depurination,
backbone modification, base modifications
ionizing radiation effect on DNA - CORRECT ANSWER - ds break
, environmental toxins effect on DNA - CORRECT ANSWER - ss break, DNA-protein
crosslink
UV light effect on DNA - CORRECT ANSWER - photoproduct, thymidine dimers
chemo effect on DNA - CORRECT ANSWER - DNA-DNA crosslink
How does proofreading work? - CORRECT ANSWER - when a mismatched pair is
recognized, respositions 3' terminus into other catalytic site with the 3' to 5' exonuclease site is
removes mismatch
moves 3' back to polymerase site
mistake is corrected
MMR fixes which replication errors? - CORRECT ANSWER - base mismatches, loops,
indels
MutH - CORRECT ANSWER - cleaves the unmethylated strand.( de novo)
Human MMR gene mutations associated with HNPCC? - CORRECT ANSWER - MSH2
and MLH1
microsatelite - CORRECT ANSWER - A short, specific and repeating sequence of
nucleotides.
MMR and microsatellite instability - CORRECT ANSWER - not repetitive because new
bases.
Exam Questions and CORRECT Answers
Central Dogma of Molecular Biology - CORRECT ANSWER - DNA -> RNA -> Protein
endogenous factors that cause DNA damage - CORRECT ANSWER - error in replication
bully addict formation
oxidation
alkylation
hydrolysis
exogenous factors that cause DNA damage - CORRECT ANSWER - UV, chemicals, x-
rays, ionizing radiation
emethanesulfate (EMS) - CORRECT ANSWER - DNA alkylation medicine for cancer
GC base pairing when guanine is exposed to EMS - CORRECT ANSWER - guanine to
06-ethylguanine and bins to thymine
EMS as a cancer treatment - CORRECT ANSWER - interferes with transcriptional and
DNA replication
alkylation event that does not change base pairing - CORRECT ANSWER - attacks
phosphodiester bond
endogenous sources of oxidative stress - CORRECT ANSWER - respiration, stress
exogenous sources of oxidative stress - CORRECT ANSWER - smoking, alcohol,
pollution, water, pesticides, medications, food (meat)
,Result of oxidative damage - CORRECT ANSWER - guanine oxidation
-biomarker of oxidative stress
-mutagenic
Hoogsteen base pairing - CORRECT ANSWER - - Occurs when one base is in the syn
conformation.
-G-A base pair
UV-A damage - CORRECT ANSWER - free radicals
UV-B damage - CORRECT ANSWER - pyrimidine dimers
Gamma and X-ray damage - CORRECT ANSWER - ss or ds DNA break, altered bases
(oxidized)
ionizing radiation - CORRECT ANSWER - radiation w/enough energy to free electrons
from atoms forming ions, may cause cancer (ex. gamma, X-rays, UV). Ionizes molecules around
DNA ( water) to form highly reactive free radicals that attack DNA backbone
oxidative stress, alkylating agents effect on DNA - CORRECT ANSWER - Base
modification: alkylation, methylation, oxidation
polycyclic aromatic hydrocarbons effect on DNA - CORRECT ANSWER - adduct
intercalation between bases
spontaneous events effect on DNA - CORRECT ANSWER - depyrimidation, depurination,
backbone modification, base modifications
ionizing radiation effect on DNA - CORRECT ANSWER - ds break
, environmental toxins effect on DNA - CORRECT ANSWER - ss break, DNA-protein
crosslink
UV light effect on DNA - CORRECT ANSWER - photoproduct, thymidine dimers
chemo effect on DNA - CORRECT ANSWER - DNA-DNA crosslink
How does proofreading work? - CORRECT ANSWER - when a mismatched pair is
recognized, respositions 3' terminus into other catalytic site with the 3' to 5' exonuclease site is
removes mismatch
moves 3' back to polymerase site
mistake is corrected
MMR fixes which replication errors? - CORRECT ANSWER - base mismatches, loops,
indels
MutH - CORRECT ANSWER - cleaves the unmethylated strand.( de novo)
Human MMR gene mutations associated with HNPCC? - CORRECT ANSWER - MSH2
and MLH1
microsatelite - CORRECT ANSWER - A short, specific and repeating sequence of
nucleotides.
MMR and microsatellite instability - CORRECT ANSWER - not repetitive because new
bases.
