WESTERN GOVERNORS UNIVERSITY
D104 Exam 1
Practice Question Bank
Genetics & Developmental Biology — NCLEX-Style Practice Questions
with Rationales
Comprehensive Review: Germline Differentiation, Fertilization, Sex
Determination & More
Edition 1 · July 2026
Table of Contents
1. Instructions for Use 2
2. Practice Questions with Answers & Rationales 2
D104 · Western Governors University Page 1
,D104 EXAM 1 PRACTICE GUIDE INSTRUCTIONS & PRACTICE QUESTIONS
How to Use This Guide
Read each stem, choose your answer, then check the rationale directly below it. The correct
option is marked, and each wrong option is explained so you understand why it's wrong — not
just that it is.
Category: Genetics & Developmental Biology — Comprehensive Exam 1
1 In fish and frogs, germline cell differentiation occurs through:
A Inherited germ plasm
B Cell-cell inductive signaling
C Environmental cues
D Maternal effect genes
Why A is correct: In fish and frogs, germline cell differentiation occurs through inherited
germ plasm (preformed determinants in the egg cytoplasm).
B — Cell-cell inductive signaling is the mechanism in mammals.
C — Environmental cues are not the primary mechanism.
D — Maternal effect genes influence early development but are not the direct mechanism
for germline differentiation.
,2 In mammals, germline cell differentiation occurs through:
A Inherited germ plasm
B Cell-cell inductive signaling
C Environmental cues
D Maternal effect genes
Why B is correct: In mammals, germline cell differentiation occurs through cell-cell
inductive signaling, not inherited germ plasm.
A — Germ plasm is used in fish and frogs, not mammals.
C — Environmental cues are not the primary mechanism.
D — Maternal effect genes influence early development but are not the direct mechanism.
3 What role does germ plasm play in specification?
A Contains maternal RNAs and proteins that direct certain embryonic cells to become
primordial germ cells
B Contains paternal RNAs and proteins
C Directs all embryonic cells to become somatic cells
D Is only found in mammals
Why A is correct: Germ plasm contains maternal RNAs and proteins that direct certain cells
to become primordial germ cells.
B — Germ plasm contains maternal, not paternal, materials.
C — Germ plasm directs cells toward germline, not somatic, fate.
D — Germ plasm is found in many species but not mammals.
, 4 Primordial germ cells (PGCs) are:
A The embryonic precursor cells that give rise to the germ line cells
B Fully differentiated gametes
C Somatic stem cells
D Cells that form the placenta
Why A is correct: Primordial germ cells are the embryonic precursor cells that give rise to
germ line cells.
B — PGCs are precursors, not fully differentiated gametes.
C — PGCs are germline, not somatic, stem cells.
D — PGCs do not form the placenta.
5 When and where do PGCs form in mammals?
A In mice, they are first identifiable around E6.5 in the proximal posterior epiblast; they
migrate to the genital ridges
B In mice, they are first identifiable at E10 in the anterior endoderm
C In mice, they form in the yolk sac and migrate to the heart
D In mice, they form in the neural tube
Why A is correct: In mice, PGCs are first identifiable around E6.5 in the proximal posterior
epiblast and migrate to the genital ridges.
B — The timing and location are incorrect.
C — PGCs do not form in the yolk sac in mammals.
D — PGCs do not form in the neural tube.
D104 Exam 1
Practice Question Bank
Genetics & Developmental Biology — NCLEX-Style Practice Questions
with Rationales
Comprehensive Review: Germline Differentiation, Fertilization, Sex
Determination & More
Edition 1 · July 2026
Table of Contents
1. Instructions for Use 2
2. Practice Questions with Answers & Rationales 2
D104 · Western Governors University Page 1
,D104 EXAM 1 PRACTICE GUIDE INSTRUCTIONS & PRACTICE QUESTIONS
How to Use This Guide
Read each stem, choose your answer, then check the rationale directly below it. The correct
option is marked, and each wrong option is explained so you understand why it's wrong — not
just that it is.
Category: Genetics & Developmental Biology — Comprehensive Exam 1
1 In fish and frogs, germline cell differentiation occurs through:
A Inherited germ plasm
B Cell-cell inductive signaling
C Environmental cues
D Maternal effect genes
Why A is correct: In fish and frogs, germline cell differentiation occurs through inherited
germ plasm (preformed determinants in the egg cytoplasm).
B — Cell-cell inductive signaling is the mechanism in mammals.
C — Environmental cues are not the primary mechanism.
D — Maternal effect genes influence early development but are not the direct mechanism
for germline differentiation.
,2 In mammals, germline cell differentiation occurs through:
A Inherited germ plasm
B Cell-cell inductive signaling
C Environmental cues
D Maternal effect genes
Why B is correct: In mammals, germline cell differentiation occurs through cell-cell
inductive signaling, not inherited germ plasm.
A — Germ plasm is used in fish and frogs, not mammals.
C — Environmental cues are not the primary mechanism.
D — Maternal effect genes influence early development but are not the direct mechanism.
3 What role does germ plasm play in specification?
A Contains maternal RNAs and proteins that direct certain embryonic cells to become
primordial germ cells
B Contains paternal RNAs and proteins
C Directs all embryonic cells to become somatic cells
D Is only found in mammals
Why A is correct: Germ plasm contains maternal RNAs and proteins that direct certain cells
to become primordial germ cells.
B — Germ plasm contains maternal, not paternal, materials.
C — Germ plasm directs cells toward germline, not somatic, fate.
D — Germ plasm is found in many species but not mammals.
, 4 Primordial germ cells (PGCs) are:
A The embryonic precursor cells that give rise to the germ line cells
B Fully differentiated gametes
C Somatic stem cells
D Cells that form the placenta
Why A is correct: Primordial germ cells are the embryonic precursor cells that give rise to
germ line cells.
B — PGCs are precursors, not fully differentiated gametes.
C — PGCs are germline, not somatic, stem cells.
D — PGCs do not form the placenta.
5 When and where do PGCs form in mammals?
A In mice, they are first identifiable around E6.5 in the proximal posterior epiblast; they
migrate to the genital ridges
B In mice, they are first identifiable at E10 in the anterior endoderm
C In mice, they form in the yolk sac and migrate to the heart
D In mice, they form in the neural tube
Why A is correct: In mice, PGCs are first identifiable around E6.5 in the proximal posterior
epiblast and migrate to the genital ridges.
B — The timing and location are incorrect.
C — PGCs do not form in the yolk sac in mammals.
D — PGCs do not form in the neural tube.
