Question 1

The primitive streak in a bird embryo is the functional equivalent to which of the following structures?

Accepted Answer

A)  the lip of the blastopore in the frog 
B)  the archenteron in a frog 
C)  the notochord in a mammal 
D)  neural crest cells in a mammal

Question 2

Which of the following correctly describes a difference between the vegetal pole of a frog zygote and the animal pole?

Accepted Answer

A)  The vegetal pole has a higher concentration of yolk. 
B)  The blastomeres originate only in the vegetal pole. 
C)  The vegetal pole cells undergo mitosis, but not cytokinesis. 
D)  The polar bodies bud from this region.

Question 3

Which correctly matches the organ with its embryonic source?

Accepted Answer

A)  adrenal medulla-endoderm 
B)  nervous system-mesoderm 
C)  kidney-mesoderm 
D)  skin-endoderm and mesoderm

Question 4

Which of the following is true about human eggs at the moment of sperm penetration?

Accepted Answer

A)  They use flagellar propulsion to move from the ovary to the oviduct. 
B)  They are still located within the ovary. 
C)  They are covered by a thin layer of calcium carbonate that prevents desiccation. 
D)  They are still surrounded by follicular cells.

Question 5

Which of the following contributions of the extra embryonic membranes was crucial for the colonization of land by vertebrate organisms?

Accepted Answer

A)  extraembryonic membranes provide an aqueous environment for embryo development 
B)  extraembryonic membranes provide nutrients that produce energy for development 
C)  extraembryonic membranes direct morphogenesis within the embryo 
D)  extraembryonic membranes give rise to crucial organ systems, like the heart and brain

Question 6

Which of the following answers best describes a feature of the plasma membrane of a sea urchin egg that is required for fertilization?

Accepted Answer

A)  It is located outside of the fertilization membrane. 
B)  It releases calcium, which initiates the fast block to polyspermy. 
C)  It has receptor molecules that specifically bind to acrosomal proteins. 
D)  It is a mesh of proteins crossing through the cytosol of the egg.

Question 7

Which of the following processes reduces the size of a tadpole's tail during metamorphosis?

Accepted Answer

A)  regeneration 
B)  apoptosis 
C)  oxidative phosphorylation 
D)  redifferentiation

Question 8

Which of the following options describes the correct outer-to-inner sequence of tissue layers in a post-gastrulation vertebrate embryo?

Accepted Answer

A)  endoderm → ectoderm → mesoderm 
B)  mesoderm → endoderm → ectoderm 
C)  ectoderm → mesoderm → endoderm 
D)  ectoderm → endoderm → mesoderm

Question 9

Which of the following cellular structures is usually reorganized when a cell changes shape?

Accepted Answer

A)  nucleus 
B)  cytoskeleton 
C)  extracellular matrix 
D)  Golgi apparatus

Question 10

Which of the following processes will be disrupted if the apical ectodermal ridge is surgically removed from an embryo?

Accepted Answer

A)  positional information for limb-bud pattern formation 
B)  guidance signals needed for correct gastrulation 
C)  unequal cytokinesis of blastomeres 
D)  the developmental substrate for the kidneys

Question 11

In C. elegans, P granules act as cytoplasmic determinants to assist with the development of the posterior end of the organism. Suppose that P granules were abnormally found in both the anterior and posterior ends of a developing C. elegans organism. What would you expect to observe?

Accepted Answer

A)  The embryo would develop with a normal anterior end and anterior structures on the posterior end. 
B)  The embryo would develop with a normal posterior end and posterior structures on the anterior end. 
C)  The embryo would develop with anterior structures on the posterior end and posterior structures on the anterior end. 
D)  The embryo would develop with a normal anterior end and a normal posterior end.

Question 12

Which of the following is required for development in all vertebrate animals?

Accepted Answer

A)  a large supply of yolk 
B)  an aqueous environment 
C)  extraembryonic membranes 
D)  a primitive streak

Question 13

Which of the following correctly matches an extraembryonic membrane with its function?

Accepted Answer

A)  amnion-waste disposal 
B)  chorion-nutrient storage 
C)  allantois-waste storage 
D)  yolk sac-gas exchange

Question 14

Which of the following correctly describes the order of events of early development from earliest to latest?

Accepted Answer

A)  first cell division → synthesis of embryo's DNA begins → acrosomal reaction → cortical reaction 
B)  cortical reaction → synthesis of embryo's DNA begins → acrosomal reaction → first cell division 
C)  cortical reaction → acrosomal reaction → first cell division → synthesis of embryo's DNA begins 
D)  acrosomal reaction → cortical reaction → synthesis of embryo's DNA begins → first cell division

Question 15

The cortical reaction of sea urchin eggs is required for which of the following events in fertilization?

Accepted Answer

A)  forming a fertilization envelope 
B)  producing a fast block to polyspermy 
C)  releasing hydrolytic enzymes from the sperm 
D)  generating an electrical impulse from the egg

Question 16

Cells transplanted from the neural tube of a frog embryo to the ventral part of another embryo develop into nervous system tissues. Which of the following claims about the transplanted cells is most consistent with the results?

Accepted Answer

A)  the cells were totipotent 
B)  the cells were determined 
C)  the cells were differentiated 
D)  the cells were mesenchymal

Question 17

Which of the following is a result of gastrulation in animals?
I. The archenteron is formed.
II. The body axes are established.
III. The germ layers are formed.

Accepted Answer

A)  I only 
B)  III only 
C)  I and III only 
D)  I, II, and III

Question 18

Which of the following statements best describes the function of the vitelline layer in a newly fertilized sea urchin egg?

Accepted Answer

A)  It lifts away from the egg and hardens to form a fertilization envelope. 
B)  It secretes hormones that enhance steroidogenesis by the ovary. 
C)  It reduces the loss of water from the egg and prevents desiccation. 
D)  It provides most of the nutrients used by the zygote.

Question 19

In some rare salamander species, all individuals are females. Reproduction relies on those females having access to sperm from males of another species. However, the resulting embryos receive no genetic contribution from the males. Given this information, what is the role of sperm in reproduction in this species?

Accepted Answer

A)  The sperm allow morphogenesis to proceed. 
B)  Sperm trigger egg activation. 
C)  Cell differentiation is initiated by the sperm. 
D)  Sperm are necessary to produce a diploid zygote.

Question 20

Embryonic induction, the influence of one group of cells on another group of cells, plays a critical role in embryonic development. In 1924, Hans Spemann and Hilde Mangold transplanted a piece of tissue from the dorsal lip of an amphibian embryo to the ventral side of another amphibian embryo. The transplanted piece of tissue influences the formation of the notochord and neural tube. If embryonic induction occurred, which of the following observations justifies the claim of embryonic induction?

Accepted Answer

A)  The transplanted tissue induced multiple limbs to develop on the ventral side of the recipient embryo. 
B)  The transplanted tissue inhibited normal cell division on the dorsal side of the recipient embryo that lead to its death. 
C)  The transplanted tissue had no effect on either the ventral or dorsal side of the recipient embryo so it continued to develop normally. 
D)  The transplanted tissue induced the formation of a second notochord and neural tube on the ventral side of the developing embryo.

Exam 46: Development in Animals