Answer:
Here is the full question on the experiment:
Experimental prediction: The effect of Ca2+ channel blockers on formation of the fertilization envelope
The role of Ca2+ ions in the formation of the fertilization envelope and blocking polyspermy can be further studied using Ca2+ channel blockers. As their name suggests, Ca2+ channel blockers block the movement of Ca2+ ions through channels. In the case of gated Ca2+ channels, the channel blockers prevent the channels from opening even if the signal to open is present.
Suppose that you conduct an experiment in which you test whether the fertilization envelope forms and polyspermy occurs under the following conditions:
Control group: An unfertilized sea urchin egg is left untreated (no Ca2+ channel blockers added). Then sperm are added.
Experimental group: Ca2+ channel blockers are added to an unfertilized sea urchin egg. Then sperm are added.
Drag the labels (yes or no) to predict whether or not the following events can occur under control conditions and experimental conditions.
Step-by-step explanation:
The sea urchin fertilization envelope (FE) is formed following initial sperm-egg interaction from the egg surface vitelline envelope (VE) and the paracrystalline protein fraction (PCF), derived from cortical granules.
Polyspermy is the fertilization of an egg by more than one sperm, and the results of such unions are lethal. If multiple sperm fertilize an egg, the embryo inherits multiple paternal centrioles. After successful fertilization of the egg cell, a block to polyspermy has to be established to avoid sterility effects associated with lethal genome imbalance and chromosome segregation defects during zygote and embryo development.
CONDITION 1
When no Ca2+ channel blocker is added:
Can fusion of sperm and egg occur? YES
Can the cytoplasmic Ca2+ concentration increase in response to the fusion of sperm and egg? YES
Can the fertilization envelope form? YES
Can polyspermy occur? NO
CONDITION 2
When a Ca2+ channel blocker is added:
Can fusion of sperm and egg occure? YES
Can the cytoplasmic Ca2+ concentration increase in response to the fusion of sperm and egg? NO
Can the fertilization envelope form? NO
Can polyspermy occur? YES