Question 1

Evaluate the following statement: The placenta is the organ where fetal and maternal blood supplies mix.

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Question 2

Refer to the figure.  Which embryo is representative of gastrulation in an amphibian, and which is representative of gastrulation in a reptile? Using the letter labels, identify which structures in the two embryos are homologous.

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Question 3

Refer to the figure showing some of the manipulations carried out by Spemann on developing amphibians.  Do the results of these experiments on salamander development indicate that gray crescent material is necessary for normal development? Do these results indicate that gray crescent material is sufficient for normal development? Explain your answer.

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Question 4

Explain how identical and non-identical twins form in humans.

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Question 5

If you were developing an embryology lab and wanted to include animals that display diverse cleavage patterns (complete and incomplete, with different orientations of mitotic spindles), which types of animals might you include? If possible, select animals that are model organisms, and list the cleavage patterns they represent.

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Question 6

Refer to the figure showing a sea urchin gastrula.  Identify the structures labelled a-g in the figure, using the following terms: archenteron, ectoderm, filopodia, primary mesenchyme, secondary mesenchyme, blastocoel, blastopore.

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Question 7

What medical condition can result if a human blastocyst hatches too early from the zona pellucida?

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Question 8

In humans, gestation lasts for approximately 9 months, which is a _______ period of time than the gestation period of horses.

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Question 9

Refer to the figure showing a 9-day chick embryo.  Match the following terms with their label numbers in the figure: allantoic membrane, allantois, amnion, body of embryo, chorion, and yolk sac.

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Question 10

What will happen if a researcher, working with developing amphibians, transplants a piece of ectoderm destined to become the epidermis (outer layer of skin) from one early gastrula to a location destined to be neural tissue in another early gastrula? What will happen if the transplant is made between late gastrulas?

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Question 11

Refer to the figure showing an embryo during early cleavage.  How do you know that this embryo is not that of a frog?

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Question 12

Are conjoined twins identical or non-identical twins, and how do they arise? Does this indicate that humans display mosaic or regulative development?

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Question 13

Although details of gastrulation differ among sea urchins, frogs, and chickens, there is a common result in all of these animals.What is it?

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Question 14

Refer to the figure showing a sea urchin gastrula.  Of the structures labeled a-g in the sea urchin gastrula, which are also found in the amphibian gastrula, and what are the names of these structures?

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Question 15

What two organelles does a sperm contribute at fertilization, and why is each one important?

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Question 16

Spina bifida is a birth defect in humans in which part of the spinal cord, as well as the adjacent area of the spine, develops abnormally.What process was disturbed during prenatal development in individuals born with spina bifida?

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Question 17

A researcher wanted to know if the dermis below the wing epidermis in a chick embryo sent inductive signals to the epidermis that resulted in the epidermis forming wing feathers.The researcher therefore did three experiments with the following results:  From these results, can we conclude that wing dermis induces epidermis to form wing feathers? Explain your answer.

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Question 18

A researcher working with frog zygotes experimentally disables the protein that inhibits GSK-3.What will be the immediate result?

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Question 19

Chorionic villus sampling, one method of prenatal genetic testing, involves taking a small sample of chorionic villi from the placenta.Why would cells from this region of the placenta reveal the genetic makeup of the fetus?

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Question 20

A researcher removes the cells containing the germ cell plasm from the vegetal region of a frog blastula.On a second frog blastula, the researcher removes cells from an area that will become the epidermal layer of the skin.What results do you predict from these experiments and why?

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Quiz 43: Animal Development

Evaluate the following statement: The placenta is the organ where fetal and maternal blood supplies mix.

Refer to the figure. Which embryo is representative of gastrulation in an amphibian, and which is representative of gastrulation in a reptile? Using the letter labels, identify which structures in the two embryos are homologous.