1|Page
PUBH 6011 REAL EXAM QUESTIONS AND
ANSWERS/ P FINAL EXAM STUDY
GUIDE 2025/2026 | A GRADE
Explain the role of the microbiome and its role in disease prevention -
ANSWER>>Microbiota → gut microbiota
- Involved in basic human biological processes
- Chronic disease have been associated with the human microbiota
Antibiotics can disrupt microbiota
The bacteria in the microbiome help digest our food, regulate our
immune system, protect against other bacteria that cause disease, and
produce vitamins including B vitamins B12, thiamine and riboflavin,
and Vitamin K, which is needed for blood coagulation.
Epigenetics - ANSWER>>the study of environmental influences on gene
expression that occur without a DNA change
DNA methylation - ANSWER>>The addition of methyl groups to bases
of DNA after DNA synthesis; may serve as a long-term control of gene
expression.
histone modification - ANSWER>>adding chemical modifications to
proteins
called histones that are involved in packaging DNA
,2|Page
micro-RNA (miRNA) - ANSWER>>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 - ANSWER>>change in 1 bp
substitution
point mutation (silent, nonsense, missense)
frameshift mutations
Macrolesions - ANSWER>>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? - ANSWER>>● 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 - ANSWER>>Causes DNA replication errors,
point
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mutations, Chromosomal abberations, also binds to DNA and is
irreversible Nongenotoxic - ANSWER>>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 - ANSWER>>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 - ANSWER>>1.
lung/ bronchus
2. colon/ rectum
3. pancreas
innate vs adaptive immunity - ANSWER>>Innate immunity: An
individual's
genetically predetermined resistance to certain diseases.
, 4|Page
Adaptive immunity: Ability of the body to react to specific microbial
infection. ANTIGEN SPECIFIC
Antibody-Antigen Interactions - ANSWER>>•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 - ANSWER>>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 - ANSWER>>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 -
ANSWER>>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.
PUBH 6011 REAL EXAM QUESTIONS AND
ANSWERS/ P FINAL EXAM STUDY
GUIDE 2025/2026 | A GRADE
Explain the role of the microbiome and its role in disease prevention -
ANSWER>>Microbiota → gut microbiota
- Involved in basic human biological processes
- Chronic disease have been associated with the human microbiota
Antibiotics can disrupt microbiota
The bacteria in the microbiome help digest our food, regulate our
immune system, protect against other bacteria that cause disease, and
produce vitamins including B vitamins B12, thiamine and riboflavin,
and Vitamin K, which is needed for blood coagulation.
Epigenetics - ANSWER>>the study of environmental influences on gene
expression that occur without a DNA change
DNA methylation - ANSWER>>The addition of methyl groups to bases
of DNA after DNA synthesis; may serve as a long-term control of gene
expression.
histone modification - ANSWER>>adding chemical modifications to
proteins
called histones that are involved in packaging DNA
,2|Page
micro-RNA (miRNA) - ANSWER>>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 - ANSWER>>change in 1 bp
substitution
point mutation (silent, nonsense, missense)
frameshift mutations
Macrolesions - ANSWER>>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? - ANSWER>>● 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 - ANSWER>>Causes DNA replication errors,
point
,3|Page
mutations, Chromosomal abberations, also binds to DNA and is
irreversible Nongenotoxic - ANSWER>>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 - ANSWER>>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 - ANSWER>>1.
lung/ bronchus
2. colon/ rectum
3. pancreas
innate vs adaptive immunity - ANSWER>>Innate immunity: An
individual's
genetically predetermined resistance to certain diseases.
, 4|Page
Adaptive immunity: Ability of the body to react to specific microbial
infection. ANTIGEN SPECIFIC
Antibody-Antigen Interactions - ANSWER>>•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 - ANSWER>>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 - ANSWER>>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 -
ANSWER>>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.
