Exam 46: Development in Animals

Which of the following is the largest cell involved in frog reproduction?

Suppose that during gastrulation in humans, a protease (an enzyme that degrades proteins) is present such that the enzymes released by the trophoblast cannot function. What is the most likely immediate outcome of this situation?

Which of the following correctly describes the sequence of developmental milestones in chordates?

The eggs of which of the following organisms contains the least amount of yolk?

The formation of the fertilization envelope in a sea urchin egg is most directly stimulated by an increase in the cytosolic concentration of which of the following ions?

The migratory neural crest cells give rise to which of the following structures?

Which of the following are found in developmental precursors to the gonadal tissues of Caenorhabditis elegans?

Thalidomide, now banned for use as a sedative during pregnancy, was used in the early 1960s by many women in their first trimester of pregnancy. Some of these women gave birth to children with limb and organ deformities. Which of the following processes did the drug most likely influence?

In which of the following pairs of organisms does holoblastic cleavage typically occur?

Treating an oocyte with a chemical that binds calcium and magnesium ions will block ________.

Just prior to the onset of gastrulation in an embryo, the "organizer" cells are specified. What would you expect in the developing embryo if the specification of these cells were experimentally blocked?

What structural adaptation in chickens allows them to lay their eggs in arid environments rather than in water?

What does the archenteron of the developing sea urchin eventually develop into?

The archenteron develops into ________.

Which of the following were Hans Spemann and colleagues studying when they developed the concept of the "organizer" in amphibian embryos?

Use the following information to answer the question. In an investigation into sperm-oocyte binding, researchers isolated the egg receptor protein, ERB1, from the sea urchin Strongylocentrotus purpuratus. ERB1 binds to the sperm acrosomal protein, bindin, during fertilization. The researchers coupled the ERB1 receptor from S. purpuratus to plastic microbeads and then mixed the ERB1-coupled beads with sperm from S. purpuratus or from the related species, S. franciscanus. A summary of the treatment mixtures and a graph of the results are shown. Treatments: A: S. purpuratus sperm mixed with S. purpuratus ERB1-coupled beads B: S. purpuratus sperm mixed with beads with no coupled ERB1 protein C: S. franciscanus sperm mixed with S. purpuratus ERB1 beads D: S. franciscanus sperm mixed with beads with no coupled ERB1 protein Which of the following conclusions is most consistent with the data?

Release of the acrosomal contents during fertilization most directly results in which of the following events?

Which of the following is a primary external factor in determining the polarity of the body axes in chick embryos?

Which of the following is most likely to occur if an amphibian zygote is manipulated so that the first cleavage plane fails to divide the gray crescent?

Which of the following correctly describes gastrulation in frog embryos?