Use the Following Information to Answer the Question

question 58

Multiple Choice

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. (Adapted from Kamei and Glabe 2003)
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

Based on the data in the graph, which of the following conclusions is supported?

• A) Plastic beads will bind to sperm from both species of sea urchin.
• B) ERB1 prevents S. franciscanus sperm from binding the beads.
• C) Sperm from S. purpuratus bind to beads only if ERB1 is present.
• D) S. franciscanus and S. purpuratus are actually the same species.

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Definitions:

Specific Phobias

Intense, irrational fears of specific objects or situations that lead to avoidance behavior and significant distress.

Learning To Fear

The process through which fear responses are acquired through experiences or observations of certain stimuli.

Anxiety Sensitivity

The tendency to catastrophically misinterpret arousal-related bodily sensations because one believes the sensations to have harmful consequences, such as death, insanity, or loss of control.

Arousal-Related Bodily Sensations

Physical sensations linked to the body's state of alertness, often experienced during excitement or stress.