• BIO 351 FINAL PRACTICE QUESTIONS AND
CORRECT ANSWERS
Which of the following is a mechanism underlying the teratogenic defects found
in embryos exposed to alcohol?
a. Increased neural crest cell proliferation.
b. lncreased neural cell adhesion mediated by protein L1.
c. lmpaired myoblast migration and differentiation.
d. lncreased apoptosis of developing neurons. - ANSWER d. Increased
apoptosis of developing neurons.
You have found that a pesticide binds with the estrogen receptor and keeps
estrogen from binding, and it does not activate the usual genes that signal
through estrogen. What type of endocrine disruptor is this? a. mimic. b. trigger.
c. blocker. - ANSWER c. blocker.
A farmer has several ewes that ate skunk cabbage or California hellebore while
they were pregnant. What potential developmental defects will be detected in
their lambs?
a. cyclopia and holoprosencephaly.
b. axial skeletal defects.
c. Mullerian duct defects.
d. Shortened limbs. - ANSWER a. cyclopia and holoprosencephaly.
When a female embryo is exposed to diethylstilbestrol it acts to block _______
expression, which in turn, leads to altered ______ expression and patterning of
the female reproductive tract. Fill in the blanks.
a. Wnt5 & Notch.
,b. Wnt7, Hoxa10 and Hoxa11.
c. Estrogen; Hoxa10.
d. Hoxa10; Hoxa11. - ANSWER b. Wnt7, Hoxa10 and Hoxa11.
You have a patient with a T shaped uterus, obstructed Fallopian tubes and clear
cell adenocarcinoma of the cervix. You believe that she was exposed to a
teratogen en utero. Which of the following is the most likely chemical
compound?
a. Vinclozolin.
b. Thalidomide.
c. Diethylstilbesterol.
d. Valproic acid. - ANSWER c. Diethylstilbesterol.
What is the embryological origin of the malleus, incus and stapes?
A. Endoderm.
B. Neural crest.
C. Head surface ectoderm.
D. Mesodermal mesenchyme.
E. Neural tube ectoderm. - ANSWER B. Neural Crest.
The scheme below illustrates the reactions catalyzed by aromatase. lf
Trachemys scripta embryos are cultured at 31C, the clutch of hatchlings should
be 100% female. lf there is a mutation in aromatase so that it is only 50%
efficient at 31C what is most likely happen to the sex ratio of the clutch?
A. 100% male
B. 50% female
C. 100% female - ANSWER B. 50% female.
, ln Hymenopteran insects such as bees, which of the following best describes
their mode of sex determination?
A. Sex is determined by aromatase function.
B. There is a single gene locus that determines sex.
C. Sex is environmentally determined.
D. They have sex chromosomes. - ANSWER B. There is a single gene locus
that determines sex.
In Drosophila how does Sex lethal (Sx/) regulate sex determination?
A lt regulates mRNA splicing.
B. lt regulates spermatogenesis.
C. It activates the X chromosome early promoter for Scute and Sisterless-4.
D. lt regulates estrogen synthesis. - ANSWER A. It regulates mRNA splicing.
Fill in the blanks. During embryonic development ________ and __________
are necessary to initiate the ovarian program of development and they induce
expression of _______.
A. Wt1, Sry, Wnt4.
B. B-catenin, Dax1, Sox9.
C. B-catenin, Sry, Sox9.
D. Rspo1, Wnt4, B-catenin. - ANSWER D. Rspo1, Wnt4, B-catenin
You have an XY female mouse with an intact SRY gene. Which of the
following genes do you think is most likely mutated in this animal?
A. Sox9.
B. B-catenin.
CORRECT ANSWERS
Which of the following is a mechanism underlying the teratogenic defects found
in embryos exposed to alcohol?
a. Increased neural crest cell proliferation.
b. lncreased neural cell adhesion mediated by protein L1.
c. lmpaired myoblast migration and differentiation.
d. lncreased apoptosis of developing neurons. - ANSWER d. Increased
apoptosis of developing neurons.
You have found that a pesticide binds with the estrogen receptor and keeps
estrogen from binding, and it does not activate the usual genes that signal
through estrogen. What type of endocrine disruptor is this? a. mimic. b. trigger.
c. blocker. - ANSWER c. blocker.
A farmer has several ewes that ate skunk cabbage or California hellebore while
they were pregnant. What potential developmental defects will be detected in
their lambs?
a. cyclopia and holoprosencephaly.
b. axial skeletal defects.
c. Mullerian duct defects.
d. Shortened limbs. - ANSWER a. cyclopia and holoprosencephaly.
When a female embryo is exposed to diethylstilbestrol it acts to block _______
expression, which in turn, leads to altered ______ expression and patterning of
the female reproductive tract. Fill in the blanks.
a. Wnt5 & Notch.
,b. Wnt7, Hoxa10 and Hoxa11.
c. Estrogen; Hoxa10.
d. Hoxa10; Hoxa11. - ANSWER b. Wnt7, Hoxa10 and Hoxa11.
You have a patient with a T shaped uterus, obstructed Fallopian tubes and clear
cell adenocarcinoma of the cervix. You believe that she was exposed to a
teratogen en utero. Which of the following is the most likely chemical
compound?
a. Vinclozolin.
b. Thalidomide.
c. Diethylstilbesterol.
d. Valproic acid. - ANSWER c. Diethylstilbesterol.
What is the embryological origin of the malleus, incus and stapes?
A. Endoderm.
B. Neural crest.
C. Head surface ectoderm.
D. Mesodermal mesenchyme.
E. Neural tube ectoderm. - ANSWER B. Neural Crest.
The scheme below illustrates the reactions catalyzed by aromatase. lf
Trachemys scripta embryos are cultured at 31C, the clutch of hatchlings should
be 100% female. lf there is a mutation in aromatase so that it is only 50%
efficient at 31C what is most likely happen to the sex ratio of the clutch?
A. 100% male
B. 50% female
C. 100% female - ANSWER B. 50% female.
, ln Hymenopteran insects such as bees, which of the following best describes
their mode of sex determination?
A. Sex is determined by aromatase function.
B. There is a single gene locus that determines sex.
C. Sex is environmentally determined.
D. They have sex chromosomes. - ANSWER B. There is a single gene locus
that determines sex.
In Drosophila how does Sex lethal (Sx/) regulate sex determination?
A lt regulates mRNA splicing.
B. lt regulates spermatogenesis.
C. It activates the X chromosome early promoter for Scute and Sisterless-4.
D. lt regulates estrogen synthesis. - ANSWER A. It regulates mRNA splicing.
Fill in the blanks. During embryonic development ________ and __________
are necessary to initiate the ovarian program of development and they induce
expression of _______.
A. Wt1, Sry, Wnt4.
B. B-catenin, Dax1, Sox9.
C. B-catenin, Sry, Sox9.
D. Rspo1, Wnt4, B-catenin. - ANSWER D. Rspo1, Wnt4, B-catenin
You have an XY female mouse with an intact SRY gene. Which of the
following genes do you think is most likely mutated in this animal?
A. Sox9.
B. B-catenin.
