Exam 46: Development in Animals

Which of the following structures releases enzymes that initiate implantation of an embryo in the endometrium?

Which of the following terms applies to a morphogenetic process whereby cells extend themselves, making the mass of the cells narrower and wider?

Which of the following outcomes would most likely occur if gastrulation was blocked?

Which of the following correctly matches a structure with the germ layer from which it is derived?

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 Based on the description of the experiment, which of the treatments would be considered a negative-control treatment for S. purpuratus sperm binding?

Which of the following structures is formed before the others during frog development?

Which of the following structures is the embryonic precursor to the human spinal cord?

During which stage of development do cells in a triploblastic embryo move to new positions to establish the three germ tissue layers?

Which of the following processes determines the arrangement of organs and tissues in their characteristic places in 3-D space?

Researchers were investigating the effects of bicoid in fruit fly development. The gene bicoid controls normal development of anterior structures in flies. In one experiment, they took a normally developing embryo and injected bicoid mRNA into the posterior end of the embryo. What result would they most likely observe?

What is a human embryo called at the time of implantation?

Under which condition will the metabolic activity in a sea urchin egg most likely be activated even in the absence of sperm?

Which of the following occurs to the blastocoel during frog development?

In humans, identical twins are possible because ________.

In sea urchins, which of the following pairs of events most directly results in the short-lasting "fast block" and the longer-lasting "slow block" to polyspermy, respectively?

In addition to maternal effect genes, paternal effect genes are important for fruit fly development. One such paternal effect gene codes for Sneaky, a protein required for breakdown of the fruit fly sperm plasma membrane that is a critical step for normal embryo development. Suppose that a female fruit fly's oocyte (egg) with a mutation in the bicoid gene is fertilized by a male fruit fly's sperm with a mutation in the Sneaky gene. Both mutations yield nonfunctional proteins. What would be the most likely outcome of this fertilization?

If an egg cell were treated with EDTA, a chemical that binds calcium and magnesium ions, ________.

Which of the following types of embryos displays meroblastic cleavage, extraembryonic membranes, and a primitive streak?

Contact between signaling molecules on a sperm membrane with receptor molecules on an oocyte membrane will most directly result in which of the following responses?

Cells transplanted from the neural tube of a frog embryo to the ventral part of another embryo develop into nervous system tissues. This result indicates that the transplanted cells were ________.