WGUD115 Advanced
D115 Advanced Pathophysiology Pathophysiology
— OA Answer Guide OA Comprehensive Study
Guide for Exam Prep
D115 Advanced Pathophysiology
Comprehensive Answer Guide & Study Reference
OA Exam Prep — Units 2 through 7
UNIT 2: Foundations of Pathophysiology — Genes, Lifestyle &
Immunity
Module 1: Genetic Influence on Patient Outcomes
Q: What are genes composed of and where are they located?
A: Genes are composed of DNA (deoxyribonucleic acid) — segments
of DNA that encode proteins. They are located on chromosomes
inside the nucleus of cells.
Q: What are the four nitrogenous bases that make up DNA?
A: Adenine (A), Thymine (T), Guanine (G), and Cytosine (C). A pairs
with T; G pairs with C. In RNA, Uracil
(U) replaces Thymine.
HIGH YIELD: A-T and G-C base pairing is a common exam
question. Remember: in RNA, T → U.
Q: How are new strands of DNA formed?
A: Through DNA replication: the double helix unwinds, and each
strand serves as a template. DNA polymerase adds complementary
nucleotides (A→T, G→C) forming two identical daughter strands.
Q: How is transcription regulated?
A: Transcription (DNA→mRNA) is regulated by promoter regions,
transcription factors, enhancers/silencers, and epigenetic
modifications (methylation, histone modification) that control
)
, whether a gene is expressed or silenced.
D115 Advanced Pathophysiology — OA Answer Guide
Q: How many pairs of chromosomes do humans have?
A: Humans have 46 chromosomes total — 23 pairs. 22 pairs are
autosomes; 1 pair are sex chromosomes (XX = female, XY = male).
Q: Most common chromosome abnormalities?
A: Trisomy 21 (Down syndrome), Monosomy X (Turner syndrome —
45,X), Trisomy XXY (Klinefelter syndrome — 47,XXY), deletions,
duplications, and translocations.
Q: How is gender determined genetically?
A: The SRY gene on the Y chromosome triggers male development.
XX = female; XY = male. Individuals with no Y chromosome develop
as female by default.
Q: What are multifactorial diseases? Name examples.
A: Diseases caused by the interaction of multiple genes AND
environmental factors. Examples: type 2 diabetes, hypertension,
coronary artery disease, cleft palate, neural tube defects,
schizophrenia.
Q: How do monozygotic and dizygotic twins differ genetically?
A: Monozygotic (identical) twins share 100% of DNA — from one
fertilized egg. Dizygotic (fraternal) twins share ~50% of DNA — from
two separate eggs fertilized by two sperm.
Q: Which chromosome is affected in Down syndrome? Clinical
features?
Page 1
)
, A: Trisomy 21 (three copies of chromosome 21). Features:
D115 Advanced Pathophysiology — OA Answer Guide
intellectual disability, flat facial profile, upslanting palpebral
fissures, single palmar crease, low-set ears, hypotonia. Risks:
congenital heart defects (AV canal), early-onset Alzheimer's,
hypothyroidism, leukemia.
HIGH YIELD: Down syndrome = Trisomy 21. Most common chromosome abnormality. Associated
with advanced maternal age.
Q: Turner syndrome — chromosomes, features, treatment?
A: Monosomy X (45,X). Features: short stature, webbed neck, shield
chest, primary amenorrhea, infertility, coarctation of aorta, bicuspid
aortic valve. Treatment: growth hormone, estrogen replacement
therapy.
Q: Klinefelter syndrome — chromosomes, features?
A: 47,XXY. Features: tall stature, small testes, gynecomastia,
infertility (azoospermia), learning difficulties. Often not diagnosed
until puberty or adulthood.
Q: Types of genetic testing?
A: Carrier screening (identifies carriers of recessive disorders),
prenatal testing (amniocentesis, CVS), newborn screening,
diagnostic testing, predictive/presymptomatic testing (e.g., BRCA
gene testing).
Module 2: Pathological Defense Mechanisms & Immunity
Q: What are the 3 layers of human defense?
A: 1st line: Physical/mechanical barriers (skin, mucous membranes,
cilia, stomach acid). 2nd line: Innate immunity (inflammation,
phagocytes, fever, complement). 3rd line: Adaptive immunity (T
cells, B cells, antibodies — specific and memory-forming).
)
, HIGH Pathophysiology
D115 Advanced YIELD: Know— the
OAsequence: Barrier → Innate (non-specific, fast) → Adaptive (specific, slow but
Answer Guide
memory).
Q: How do acute and chronic inflammation differ?
A: Acute inflammation: rapid onset (minutes-hours), dominated by
neutrophils, vascular changes (redness, heat, swelling, pain, loss
of function), usually resolves. Chronic inflammation: weeks-
months, dominated by macrophages and lymphocytes, may cause
tissue destruction and fibrosis (e.g., rheumatoid arthritis, TB).
Q: What are the phases of wound healing?
A: 1) Hemostasis (0–24 hrs): vasoconstriction, platelet plug, clot
formation. 2) Inflammation (1–3 days): neutrophils then
macrophages clean debris. 3) Proliferation (3–21 days): fibroblasts
lay collagen, angiogenesis, epithelialization. 4) Remodeling (21
days–2 years): collagen reorganizes, scar matures.
Q: Describe the process of adaptive immunity.
A: Antigen is presented by APCs (antigen-presenting cells) via MHC
molecules. Naïve T cells are activated and differentiate into helper T
cells (CD4+) and cytotoxic T cells (CD8+). B cells are activated
(with T cell help) → differentiate into plasma cells that produce
antibodies. Memory cells are formed for faster future responses.
Q: Identify the 4 types of hypersensitivity reactions.
A: Type I (Immediate/Anaphylactic): IgE mediated, mast
cells/basophils, occurs within minutes. Examples: anaphylaxis,
allergic asthma, hay fever. Type II (Cytotoxic): IgG/IgM against cell
surface antigens. Examples: hemolytic transfusion reactions,
Graves disease. Type III (Immune complex): IgG/IgM complexes
deposit in tissues. Examples: SLE, serum sickness,
glomerulonephritis. Type IV (Delayed/Cell-mediated): T cell
mediated, 48–72 hrs. Examples: contact dermatitis, TB skin test,
transplant rejection.
)
D115 Advanced Pathophysiology Pathophysiology
— OA Answer Guide OA Comprehensive Study
Guide for Exam Prep
D115 Advanced Pathophysiology
Comprehensive Answer Guide & Study Reference
OA Exam Prep — Units 2 through 7
UNIT 2: Foundations of Pathophysiology — Genes, Lifestyle &
Immunity
Module 1: Genetic Influence on Patient Outcomes
Q: What are genes composed of and where are they located?
A: Genes are composed of DNA (deoxyribonucleic acid) — segments
of DNA that encode proteins. They are located on chromosomes
inside the nucleus of cells.
Q: What are the four nitrogenous bases that make up DNA?
A: Adenine (A), Thymine (T), Guanine (G), and Cytosine (C). A pairs
with T; G pairs with C. In RNA, Uracil
(U) replaces Thymine.
HIGH YIELD: A-T and G-C base pairing is a common exam
question. Remember: in RNA, T → U.
Q: How are new strands of DNA formed?
A: Through DNA replication: the double helix unwinds, and each
strand serves as a template. DNA polymerase adds complementary
nucleotides (A→T, G→C) forming two identical daughter strands.
Q: How is transcription regulated?
A: Transcription (DNA→mRNA) is regulated by promoter regions,
transcription factors, enhancers/silencers, and epigenetic
modifications (methylation, histone modification) that control
)
, whether a gene is expressed or silenced.
D115 Advanced Pathophysiology — OA Answer Guide
Q: How many pairs of chromosomes do humans have?
A: Humans have 46 chromosomes total — 23 pairs. 22 pairs are
autosomes; 1 pair are sex chromosomes (XX = female, XY = male).
Q: Most common chromosome abnormalities?
A: Trisomy 21 (Down syndrome), Monosomy X (Turner syndrome —
45,X), Trisomy XXY (Klinefelter syndrome — 47,XXY), deletions,
duplications, and translocations.
Q: How is gender determined genetically?
A: The SRY gene on the Y chromosome triggers male development.
XX = female; XY = male. Individuals with no Y chromosome develop
as female by default.
Q: What are multifactorial diseases? Name examples.
A: Diseases caused by the interaction of multiple genes AND
environmental factors. Examples: type 2 diabetes, hypertension,
coronary artery disease, cleft palate, neural tube defects,
schizophrenia.
Q: How do monozygotic and dizygotic twins differ genetically?
A: Monozygotic (identical) twins share 100% of DNA — from one
fertilized egg. Dizygotic (fraternal) twins share ~50% of DNA — from
two separate eggs fertilized by two sperm.
Q: Which chromosome is affected in Down syndrome? Clinical
features?
Page 1
)
, A: Trisomy 21 (three copies of chromosome 21). Features:
D115 Advanced Pathophysiology — OA Answer Guide
intellectual disability, flat facial profile, upslanting palpebral
fissures, single palmar crease, low-set ears, hypotonia. Risks:
congenital heart defects (AV canal), early-onset Alzheimer's,
hypothyroidism, leukemia.
HIGH YIELD: Down syndrome = Trisomy 21. Most common chromosome abnormality. Associated
with advanced maternal age.
Q: Turner syndrome — chromosomes, features, treatment?
A: Monosomy X (45,X). Features: short stature, webbed neck, shield
chest, primary amenorrhea, infertility, coarctation of aorta, bicuspid
aortic valve. Treatment: growth hormone, estrogen replacement
therapy.
Q: Klinefelter syndrome — chromosomes, features?
A: 47,XXY. Features: tall stature, small testes, gynecomastia,
infertility (azoospermia), learning difficulties. Often not diagnosed
until puberty or adulthood.
Q: Types of genetic testing?
A: Carrier screening (identifies carriers of recessive disorders),
prenatal testing (amniocentesis, CVS), newborn screening,
diagnostic testing, predictive/presymptomatic testing (e.g., BRCA
gene testing).
Module 2: Pathological Defense Mechanisms & Immunity
Q: What are the 3 layers of human defense?
A: 1st line: Physical/mechanical barriers (skin, mucous membranes,
cilia, stomach acid). 2nd line: Innate immunity (inflammation,
phagocytes, fever, complement). 3rd line: Adaptive immunity (T
cells, B cells, antibodies — specific and memory-forming).
)
, HIGH Pathophysiology
D115 Advanced YIELD: Know— the
OAsequence: Barrier → Innate (non-specific, fast) → Adaptive (specific, slow but
Answer Guide
memory).
Q: How do acute and chronic inflammation differ?
A: Acute inflammation: rapid onset (minutes-hours), dominated by
neutrophils, vascular changes (redness, heat, swelling, pain, loss
of function), usually resolves. Chronic inflammation: weeks-
months, dominated by macrophages and lymphocytes, may cause
tissue destruction and fibrosis (e.g., rheumatoid arthritis, TB).
Q: What are the phases of wound healing?
A: 1) Hemostasis (0–24 hrs): vasoconstriction, platelet plug, clot
formation. 2) Inflammation (1–3 days): neutrophils then
macrophages clean debris. 3) Proliferation (3–21 days): fibroblasts
lay collagen, angiogenesis, epithelialization. 4) Remodeling (21
days–2 years): collagen reorganizes, scar matures.
Q: Describe the process of adaptive immunity.
A: Antigen is presented by APCs (antigen-presenting cells) via MHC
molecules. Naïve T cells are activated and differentiate into helper T
cells (CD4+) and cytotoxic T cells (CD8+). B cells are activated
(with T cell help) → differentiate into plasma cells that produce
antibodies. Memory cells are formed for faster future responses.
Q: Identify the 4 types of hypersensitivity reactions.
A: Type I (Immediate/Anaphylactic): IgE mediated, mast
cells/basophils, occurs within minutes. Examples: anaphylaxis,
allergic asthma, hay fever. Type II (Cytotoxic): IgG/IgM against cell
surface antigens. Examples: hemolytic transfusion reactions,
Graves disease. Type III (Immune complex): IgG/IgM complexes
deposit in tissues. Examples: SLE, serum sickness,
glomerulonephritis. Type IV (Delayed/Cell-mediated): T cell
mediated, 48–72 hrs. Examples: contact dermatitis, TB skin test,
transplant rejection.
)
