UCF BIOLOGY EXIT EXAM NEWEST EXAM 2026-
2027 COMPLETE 150 QUESTIONS AND
CORRECT DETAILED ANSWERS (VERIFIED
ANSWERS) ALREADY GRADED A+
181) In an egg cell treated with EDTA, a chemical that binds calcium and magnesium ions, the
a) acrosomal reaction would be blocked.
b) fusion of sperm and egg nuclei would be blocked.
c) fast block to polyspermy would not occur.
d) fertilization envelope would not be formed.
e) zygote would not contain maternal and paternal chromosomes. - CORRECT ANSWER: D
182) In mammals, the nuclei resulting from the union of the sperm and the egg are first truly
diploid at the end of the
a) acrosomal reaction.
b) completion of spermatogenesis.
c) initial cleavage.
d) activation of the egg.
e) completion of gastrulation. - CORRECT ANSWER: C
183) In mammalian eggs, the receptors for sperm are found in the
a) fertilization membrane.
b) zona pellucida.
c) cytosol of the egg.
d) nucleus of the egg.
e) mitochondria of the egg. - CORRECT ANSWER: B
184) Compared to sea urchin eggs, those of mammals
,a) complete the fertilization process more rapidly.
b) have not already completed meiosis at the time of ovulation.
c) have a more distinct animal pole.
d) have a more distinct vegetal pole.
e) have no requirement for the cortical reaction. - CORRECT ANSWER: B
185) As cleavage continues during frog development, the size of the blastomeres
a) increases as the number of the blastomeres decreases.
b) increases as the number of the blastomeres increases.
c) decreases as the number of the blastomeres increases.
d) decreases as the number of the blastomeres decreases.
e) increases as the number of the blastomeres stays the same. - CORRECT ANSWER: C
186) The vegetal pole of the zygote differs from the animal pole in that
a) the vegetal pole has a higher concentration of yolk.
b) the blastomeres originate only in the vegetal pole.
c) the posterior end of the embryo forms at the vegetal pole.
d) the vegetal pole cells undergo mitosis but not cytokinesis.
e) the polar bodies bud from this region. - CORRECT ANSWER: A
187) The small portion of the embryo that will become its dorsal side develops from the
a) morula.
b) primitive streak.
c) archenteron.
d) gray crescent.
e) blastocoel. - CORRECT ANSWER: D
,188) The yolk of the frog egg
a) prevents gastrulation.
b) is concentrated at the animal pole.
c) is homogeneously arranged in the egg.
d) impedes the formation of a primitive streak.
e) supports the higher rate of cleavage at the animal pole compared to the vegetal pole. -
CORRECT ANSWER: E
189) An embryo with meroblastic cleavage, extra-embryonic membranes, and a primitive streak
must be that of
a) an insect.
b) a fish.
c) an amphibian.
d) a bird.
e) a sea urchin. - CORRECT ANSWER: D
190) Meroblastic cleavage occurs in
a) sea urchins, but not humans or birds.
b) humans, but not sea urchins or birds.
c) birds, but not sea urchins or humans.
d) both sea urchins and birds, but not humans.
e) both humans and birds, but not sea urchins. - CORRECT ANSWER: C
191) The outer-to-inner sequence of tissue layers in a post-gastrulation vertebrate embryo is
a) endoderm ectoderm mesoderm.
b) mesoderm endoderm ectoderm.
c) ectoderm mesoderm endoderm.
d) ectoderm endoderm mesoderm.
, e) endoderm mesoderm ectoderm. - CORRECT ANSWER: C
192) If gastrulation was blocked by an environmental toxin, then
a) cleavage would not occur in the zygote.
b) embryonic germ layers would not form.
c) fertilization would be blocked.
d) the blastula would not be formed.
e) the blastopore would form above the gray crescent in the animal pole. - CORRECT
ANSWER: B
193) The archenteron of the developing frog eventually develops into the
a) reproductive organs.
b) the blastocoel.
c) heart and lungs.
d) digestive tract.
e) brain and spinal cord. - CORRECT ANSWER: D
194) Although it contributes no cells to the embryo, this structure guides the formation of the
primitive streak:
a) endoderm
b) mesoderm
c) ectoderm
d) neural crest
e) hypoblast - CORRECT ANSWER: E
195) Uterine implantation due to enzymatic digestion of the endometrium is initiated by
a) the inner cell mass.
b) the endoderm.
2027 COMPLETE 150 QUESTIONS AND
CORRECT DETAILED ANSWERS (VERIFIED
ANSWERS) ALREADY GRADED A+
181) In an egg cell treated with EDTA, a chemical that binds calcium and magnesium ions, the
a) acrosomal reaction would be blocked.
b) fusion of sperm and egg nuclei would be blocked.
c) fast block to polyspermy would not occur.
d) fertilization envelope would not be formed.
e) zygote would not contain maternal and paternal chromosomes. - CORRECT ANSWER: D
182) In mammals, the nuclei resulting from the union of the sperm and the egg are first truly
diploid at the end of the
a) acrosomal reaction.
b) completion of spermatogenesis.
c) initial cleavage.
d) activation of the egg.
e) completion of gastrulation. - CORRECT ANSWER: C
183) In mammalian eggs, the receptors for sperm are found in the
a) fertilization membrane.
b) zona pellucida.
c) cytosol of the egg.
d) nucleus of the egg.
e) mitochondria of the egg. - CORRECT ANSWER: B
184) Compared to sea urchin eggs, those of mammals
,a) complete the fertilization process more rapidly.
b) have not already completed meiosis at the time of ovulation.
c) have a more distinct animal pole.
d) have a more distinct vegetal pole.
e) have no requirement for the cortical reaction. - CORRECT ANSWER: B
185) As cleavage continues during frog development, the size of the blastomeres
a) increases as the number of the blastomeres decreases.
b) increases as the number of the blastomeres increases.
c) decreases as the number of the blastomeres increases.
d) decreases as the number of the blastomeres decreases.
e) increases as the number of the blastomeres stays the same. - CORRECT ANSWER: C
186) The vegetal pole of the zygote differs from the animal pole in that
a) the vegetal pole has a higher concentration of yolk.
b) the blastomeres originate only in the vegetal pole.
c) the posterior end of the embryo forms at the vegetal pole.
d) the vegetal pole cells undergo mitosis but not cytokinesis.
e) the polar bodies bud from this region. - CORRECT ANSWER: A
187) The small portion of the embryo that will become its dorsal side develops from the
a) morula.
b) primitive streak.
c) archenteron.
d) gray crescent.
e) blastocoel. - CORRECT ANSWER: D
,188) The yolk of the frog egg
a) prevents gastrulation.
b) is concentrated at the animal pole.
c) is homogeneously arranged in the egg.
d) impedes the formation of a primitive streak.
e) supports the higher rate of cleavage at the animal pole compared to the vegetal pole. -
CORRECT ANSWER: E
189) An embryo with meroblastic cleavage, extra-embryonic membranes, and a primitive streak
must be that of
a) an insect.
b) a fish.
c) an amphibian.
d) a bird.
e) a sea urchin. - CORRECT ANSWER: D
190) Meroblastic cleavage occurs in
a) sea urchins, but not humans or birds.
b) humans, but not sea urchins or birds.
c) birds, but not sea urchins or humans.
d) both sea urchins and birds, but not humans.
e) both humans and birds, but not sea urchins. - CORRECT ANSWER: C
191) The outer-to-inner sequence of tissue layers in a post-gastrulation vertebrate embryo is
a) endoderm ectoderm mesoderm.
b) mesoderm endoderm ectoderm.
c) ectoderm mesoderm endoderm.
d) ectoderm endoderm mesoderm.
, e) endoderm mesoderm ectoderm. - CORRECT ANSWER: C
192) If gastrulation was blocked by an environmental toxin, then
a) cleavage would not occur in the zygote.
b) embryonic germ layers would not form.
c) fertilization would be blocked.
d) the blastula would not be formed.
e) the blastopore would form above the gray crescent in the animal pole. - CORRECT
ANSWER: B
193) The archenteron of the developing frog eventually develops into the
a) reproductive organs.
b) the blastocoel.
c) heart and lungs.
d) digestive tract.
e) brain and spinal cord. - CORRECT ANSWER: D
194) Although it contributes no cells to the embryo, this structure guides the formation of the
primitive streak:
a) endoderm
b) mesoderm
c) ectoderm
d) neural crest
e) hypoblast - CORRECT ANSWER: E
195) Uterine implantation due to enzymatic digestion of the endometrium is initiated by
a) the inner cell mass.
b) the endoderm.
