Use the Following Information to Answer the Question

question 41

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

• A) Treatment A
• B) Treatment B
• C) Treatment C
• D) Treatment D

---

Definitions:

Nutrients

Substances obtained from food that are vital for growth, metabolism, and for maintaining health.

Small Intestine

A part of the digestive system where most of the digestion and absorption of nutrients and minerals from food occurs.

Digestive System

The digestive system is a series of organs responsible for breaking down food, absorbing nutrients, and eliminating waste.

Toxic Accumulation

The build-up of harmful substances within an organism or environment, which can lead to adverse effects.