Between fertilization and the first cleavage division, actin filaments pull the cytoplasm of the frog egg toward the point of sperm entry in a process called:

#Question id: 31224

#Unit 4. Cell Communication and Cell Signaling

#Question id: 1276

#Unit 4. Cell Communication and Cell Signaling

Which of the following does not belong to the major families of cell surface adhesion molecules?

#Question id: 968

#Unit 1. Molecules and their Interaction Relevant to Biology

In the urea cycle which molecule is transported from the mitochondrial matrix to the cytosol as ornithine is transported in the opposite direction?

#Question id: 5648

#Unit 5. Developmental Biology

Use the following information to answer the question. In order to test how sea urchin sperm bind to eggs, scientists isolated the egg receptor protein that binds to the sperm acrosomal protein called bindin. Plastic beads were coated with egg receptor for bindin (ERB1) from eggs of the sea urchin Strongylocentrotus purpuratus, and then the beads mixed with sperm from S. purpuratus or from the related species, S. franciscanus. The researchers counted how many sperm were bound to each bead. The results are shown in the graph below. Treatments:

A: S. purpuratus sperm mixed with S. purpuratus ERB1 beads

B: S. purpuratus sperm mixed with beads containing no ERB1 protein

C: S. franciscanus sperm mixed with S. purpuratus ERB1 beads

D: S. franciscanus sperm mixed with beads containing no ERB1 protein

 What is a broader implication from the observations of the experiment?

#Question id: 8716

#Unit 9. Diversity of Life Forms

The most important feature that permits a gene to act as a molecular clock is ________.