BIO 351 Exam 2 Review Questions
with Correct Answers 100% Pass
The Primitive streak plays a key role in gastrulation. Where is the primitive streak
located in the 24 hr old chick embryo? - ✔✔B
Which of the following cell types is formed from epiblast cells that migrate through the
primitive streak? - ✔✔Mesoderm - the mesoderm forms the epiblast cells migrating
through the primitive streak.
- Remember that the definitive endoderm also forms the migration through the
primitive streak.
Why isn't the ectoderm formed from epiblast cells that migrate through the primitive
streak? - ✔✔The ectoderm forms from the remaining epiblast that does not migrate
through the primitive streak
Why isn't the primary hypoblast formed from epiblast cells that migrate through the
primitive streak? - ✔✔The primary hypoblast forms from islands of cells ventral to the
epiblast.
All the cells of the embryo proper (all the cells in your body now) derive from which of
the following cells? - ✔✔Epiblast
Which of the following is the epiblast? - ✔✔Refer to image on question 4 on Sep. 17th
lecture questions,
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, Answer: C
Which of the following is the anterior visceral endoderm? - ✔✔C
In the mammalian embryo, which structure is essential to set up the anterior-posterior
axis? - ✔✔Anterior visceral endoderm
Inner cell mass - ✔✔determines the proximal-distal (dorsal-ventral) axis
Node - ✔✔key to forming left-right asymmetry
sperm entry site - ✔✔determines the initial axis (anima-vegetal)
primitive streak - ✔✔forms after AVE
The neural tube forms from the folding of the neural plate. Which region of the neural
plate fuses together to form the dorsal neural tube? - ✔✔Refer to Q1 from 09/24 clicker
question.
Answer: C
The neural tube forms from the folding of the neural plate. Which region of the neural
tube is the first to close? - ✔✔The middle
A 25 year-old woman who is pregnant for the first time undergoes amniocentesis
during the 25th week of pregnancy. The testing reveals an increased level of
acetylcholinesterase in the amniotic fluid. Acetylcholinesterase is normally produced in
the CNS and cannot cross the blood brain barrier. This test suggests which of the
following fetal abnormalities? - ✔✔Anencephaly, the neural tube is open in the head
and exposed to amniotic fluid.
Gastrulation defect - ✔✔the embryo would not survive to 25 weeks without mesoderm
formed during gastrulation
COPYRIGHT © 2025 BY SOPHIA BENNETT, ALL RIGHTS RESERVED 2
with Correct Answers 100% Pass
The Primitive streak plays a key role in gastrulation. Where is the primitive streak
located in the 24 hr old chick embryo? - ✔✔B
Which of the following cell types is formed from epiblast cells that migrate through the
primitive streak? - ✔✔Mesoderm - the mesoderm forms the epiblast cells migrating
through the primitive streak.
- Remember that the definitive endoderm also forms the migration through the
primitive streak.
Why isn't the ectoderm formed from epiblast cells that migrate through the primitive
streak? - ✔✔The ectoderm forms from the remaining epiblast that does not migrate
through the primitive streak
Why isn't the primary hypoblast formed from epiblast cells that migrate through the
primitive streak? - ✔✔The primary hypoblast forms from islands of cells ventral to the
epiblast.
All the cells of the embryo proper (all the cells in your body now) derive from which of
the following cells? - ✔✔Epiblast
Which of the following is the epiblast? - ✔✔Refer to image on question 4 on Sep. 17th
lecture questions,
COPYRIGHT © 2025 BY SOPHIA BENNETT, ALL RIGHTS RESERVED 1
, Answer: C
Which of the following is the anterior visceral endoderm? - ✔✔C
In the mammalian embryo, which structure is essential to set up the anterior-posterior
axis? - ✔✔Anterior visceral endoderm
Inner cell mass - ✔✔determines the proximal-distal (dorsal-ventral) axis
Node - ✔✔key to forming left-right asymmetry
sperm entry site - ✔✔determines the initial axis (anima-vegetal)
primitive streak - ✔✔forms after AVE
The neural tube forms from the folding of the neural plate. Which region of the neural
plate fuses together to form the dorsal neural tube? - ✔✔Refer to Q1 from 09/24 clicker
question.
Answer: C
The neural tube forms from the folding of the neural plate. Which region of the neural
tube is the first to close? - ✔✔The middle
A 25 year-old woman who is pregnant for the first time undergoes amniocentesis
during the 25th week of pregnancy. The testing reveals an increased level of
acetylcholinesterase in the amniotic fluid. Acetylcholinesterase is normally produced in
the CNS and cannot cross the blood brain barrier. This test suggests which of the
following fetal abnormalities? - ✔✔Anencephaly, the neural tube is open in the head
and exposed to amniotic fluid.
Gastrulation defect - ✔✔the embryo would not survive to 25 weeks without mesoderm
formed during gastrulation
COPYRIGHT © 2025 BY SOPHIA BENNETT, ALL RIGHTS RESERVED 2
