PUBH 6011 COMPREHENSIVE EXAMS ALL
QUESTIONS AND ANSWERS SET A+
✔✔DNA methylation - ✔✔The addition of methyl groups to bases of DNA after DNA
synthesis; may serve as a long-term control of gene expression.
✔✔histone modification - ✔✔adding chemical modifications to proteins called histones
that are involved in packaging DNA
✔✔micro-RNA (miRNA) - ✔✔A small, single-stranded RNA molecule that binds to a
complementary sequence in mRNA molecules and directs associated proteins to
degrade or prevent translation of the target mRNA.
✔✔Microlesions - ✔✔change in 1 bp
substitution
point mutation (silent, nonsense, missense)
frameshift mutations
✔✔Macrolesions - ✔✔chromosome aberrations
- Often caused by effects on mitotic machinery, not DNA
- Change in chromosome structure
- Deletion, duplication, inversion, translocation—may be stable
- Acentric fragments, dicentric chromosomes—usually cell death
change in chromosome number
- aneuploidy
- polyploidy
✔✔Why do mutations matter? - ✔✔● Polymorphisms can change the function of
proteins
,● Many proteins (e.g., enzymes, receptors) associated with response to chemicals,
drugs, and so on
● Effect may be silent, advantageous, or disadvantageous
○ Example: Change in SNP can make people less drug dependent
✔✔genotoxic carcinogens - ✔✔Causes DNA replication errors, point mutations,
Chromosomal abberations, also binds to DNA and is irreversible
✔✔Nongenotoxic - ✔✔carcinogens that modify gene expression but do not damage
DNA
induce cancer through hormonal effects, cell proliferation, increase change of replication
errors, increase number of cells at risk
✔✔mutations and cancer - ✔✔Cancer-causing mutations typically occur in two
categories of genes
proto-oncogenes: leading to altered forms of normal cellular genes usually involved in
cell signaling and growth control
tumor suppressor genes: whose protein products help regulate proliferation of normal
cells- act as a "brake"- or promote programmed cell death (apoptosis)
✔✔Three cancer types with highest mortality in the US - ✔✔1. lung/ bronchus
2. colon/ rectum
3. pancreas
✔✔innate vs adaptive immunity - ✔✔Innate immunity: An individual's genetically
predetermined resistance to certain diseases.
Adaptive immunity: Ability of the body to react to specific microbial infection. ANTIGEN
SPECIFIC
✔✔Antibody-Antigen Interactions - ✔✔•Complementary fit between antigen and
antibody is needed
•The better the fit the better the stimulation of the lymphocytes
Can be multiple antigens on one pathogen cell (can be proteins, sugars, etc), each
recognized with a different antibody
✔✔Vaccines - ✔✔dose of a disabled or destroyed pathogen used to stimulate a long-
term immune defense against the pathogen. A weakened form of the virus is given to
the person so their immune system can build up immunity to the virus.
, ✔✔first pass effect - ✔✔The initial metabolism in the liver of a drug absorbed from the
gastrointestinal tract before the drug reaches systemic circulation through the
bloodstream.
Concentration of the drug is greatly reduced before it reaches circulation
✔✔role of liver in breaking down food, microbes, and chemical toxins - ✔✔The largest
gland in the body that breaks down nutrients and builds up body tissue. It acts as a
storage site for minerals and vitamins. Red blood cells and Kupffer cells (cells that help
eliminate harmful microorganisms as they move through the blood) are produced in the
liver. Glycogen is also produced in the liver and it is regulated throughout the body. Vital
when it comes to metabolic processes and disposal of toxins.
The liver converts fat soluble toxins to water soluble substances that an be excreted.
The enzymatic process to dispose of toxins happens in 2 phases: phase 1 (oxidation)
and phase 2 (conjugation).
■ Phase 1: neutralizes toxins or changes the toxic chemical to form activated
compounds that will be neutralized in stage 2. This makes toxic chemicals less harmful.
Free radicals are produced (too many can damage the liver), the effects of which are
reduced by antioxidants.
■ Phase 2: Conjugation pathway causes the liver cells to add another substance to the
toxic chemical to make it less harmful. This makes the toxin water-soluble so it can be
excreted as bile or urine.
✔✔Variability in metabolism - ✔✔can affect the activity of drugs
✔✔dose-response relationship - ✔✔Relationship between an administered dose and
the effect on an organism
majority of response are at mean
- Knowledge of the dose-response relationship establishes:
o Causality — that the chemical has induced the observed effects
o The threshold effect — the lowest dose where an induced effect occurs.
o The slope for the dose response — the rate at which injury builds up.
o Within a population, the majority of responses to a toxicant are similar; however, there
are differences in how responses may be encountered - some individuals are
susceptible and others resistant. As demonstrated in Animation 1, a graph of the
individual responses can be depicted as a bell-shaped standard distribution curve.
There is a wide variance in responses as demonstrated by the mild reaction in resistant
individuals, the typical response in the majority of individuals, and the severe reaction in
sensitive individuals.
○ The variation can be due to genres, nutrition, health status, etc.
QUESTIONS AND ANSWERS SET A+
✔✔DNA methylation - ✔✔The addition of methyl groups to bases of DNA after DNA
synthesis; may serve as a long-term control of gene expression.
✔✔histone modification - ✔✔adding chemical modifications to proteins called histones
that are involved in packaging DNA
✔✔micro-RNA (miRNA) - ✔✔A small, single-stranded RNA molecule that binds to a
complementary sequence in mRNA molecules and directs associated proteins to
degrade or prevent translation of the target mRNA.
✔✔Microlesions - ✔✔change in 1 bp
substitution
point mutation (silent, nonsense, missense)
frameshift mutations
✔✔Macrolesions - ✔✔chromosome aberrations
- Often caused by effects on mitotic machinery, not DNA
- Change in chromosome structure
- Deletion, duplication, inversion, translocation—may be stable
- Acentric fragments, dicentric chromosomes—usually cell death
change in chromosome number
- aneuploidy
- polyploidy
✔✔Why do mutations matter? - ✔✔● Polymorphisms can change the function of
proteins
,● Many proteins (e.g., enzymes, receptors) associated with response to chemicals,
drugs, and so on
● Effect may be silent, advantageous, or disadvantageous
○ Example: Change in SNP can make people less drug dependent
✔✔genotoxic carcinogens - ✔✔Causes DNA replication errors, point mutations,
Chromosomal abberations, also binds to DNA and is irreversible
✔✔Nongenotoxic - ✔✔carcinogens that modify gene expression but do not damage
DNA
induce cancer through hormonal effects, cell proliferation, increase change of replication
errors, increase number of cells at risk
✔✔mutations and cancer - ✔✔Cancer-causing mutations typically occur in two
categories of genes
proto-oncogenes: leading to altered forms of normal cellular genes usually involved in
cell signaling and growth control
tumor suppressor genes: whose protein products help regulate proliferation of normal
cells- act as a "brake"- or promote programmed cell death (apoptosis)
✔✔Three cancer types with highest mortality in the US - ✔✔1. lung/ bronchus
2. colon/ rectum
3. pancreas
✔✔innate vs adaptive immunity - ✔✔Innate immunity: An individual's genetically
predetermined resistance to certain diseases.
Adaptive immunity: Ability of the body to react to specific microbial infection. ANTIGEN
SPECIFIC
✔✔Antibody-Antigen Interactions - ✔✔•Complementary fit between antigen and
antibody is needed
•The better the fit the better the stimulation of the lymphocytes
Can be multiple antigens on one pathogen cell (can be proteins, sugars, etc), each
recognized with a different antibody
✔✔Vaccines - ✔✔dose of a disabled or destroyed pathogen used to stimulate a long-
term immune defense against the pathogen. A weakened form of the virus is given to
the person so their immune system can build up immunity to the virus.
, ✔✔first pass effect - ✔✔The initial metabolism in the liver of a drug absorbed from the
gastrointestinal tract before the drug reaches systemic circulation through the
bloodstream.
Concentration of the drug is greatly reduced before it reaches circulation
✔✔role of liver in breaking down food, microbes, and chemical toxins - ✔✔The largest
gland in the body that breaks down nutrients and builds up body tissue. It acts as a
storage site for minerals and vitamins. Red blood cells and Kupffer cells (cells that help
eliminate harmful microorganisms as they move through the blood) are produced in the
liver. Glycogen is also produced in the liver and it is regulated throughout the body. Vital
when it comes to metabolic processes and disposal of toxins.
The liver converts fat soluble toxins to water soluble substances that an be excreted.
The enzymatic process to dispose of toxins happens in 2 phases: phase 1 (oxidation)
and phase 2 (conjugation).
■ Phase 1: neutralizes toxins or changes the toxic chemical to form activated
compounds that will be neutralized in stage 2. This makes toxic chemicals less harmful.
Free radicals are produced (too many can damage the liver), the effects of which are
reduced by antioxidants.
■ Phase 2: Conjugation pathway causes the liver cells to add another substance to the
toxic chemical to make it less harmful. This makes the toxin water-soluble so it can be
excreted as bile or urine.
✔✔Variability in metabolism - ✔✔can affect the activity of drugs
✔✔dose-response relationship - ✔✔Relationship between an administered dose and
the effect on an organism
majority of response are at mean
- Knowledge of the dose-response relationship establishes:
o Causality — that the chemical has induced the observed effects
o The threshold effect — the lowest dose where an induced effect occurs.
o The slope for the dose response — the rate at which injury builds up.
o Within a population, the majority of responses to a toxicant are similar; however, there
are differences in how responses may be encountered - some individuals are
susceptible and others resistant. As demonstrated in Animation 1, a graph of the
individual responses can be depicted as a bell-shaped standard distribution curve.
There is a wide variance in responses as demonstrated by the mild reaction in resistant
individuals, the typical response in the majority of individuals, and the severe reaction in
sensitive individuals.
○ The variation can be due to genres, nutrition, health status, etc.
