In the block to polyspermy, entry of the sperm's contents causes calcium ion levels in the oocyte's cytoplasm to rise, triggering the cortical reaction.
In biology, polyspermy describes the fertilization of an egg by more than one sperm. Diploid organisms normally contain two copies of each chromosome, one from each parent.
The cell resulting from polyspermy, on the other hand, contains three or more copies of each chromosome—one from the egg and one each from multiple sperm. Usually, the result is an unviable zygote. This may occur because sperm are too efficient at reaching and fertilizing eggs due to the selective pressures of sperm competition.
The cortical reaction is a calcium-dependent exocytotic process in which the content of secretory granules is released into the perivitellin space immediately after fertilization, which serves to prevent polyspermic fertilization.
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All neurotransmitter receptors should be thought of as having two functions: First, to detect a particular neurotransmitter, and second, to do something<span> when they detect it. The receptor determines what the neurotransmitter's effect is. So it's not always right to call a neurotransmitter inhibitory or excitatory. Glutamate, for example, is among the most common neurotransmitters, and it's almost always excitatory... Except when it binds to a particular type of glutamate receptor, which is inhibitory. Done dopamine receptors are excitatory, some are inhibitory, and not all receptors have effects that fit neatly into those two categories. Sometimes a receptor will have an effect on something completely different... When the NMDA subtype of glutamate receptor is activated, for example, it can cause the postsynaptic cell to change what receptors it puts at that synapse (a cell can have different receptors at different synapses!). Your welcome!
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A catalyst<span> is a chemical that increases the rate of a chemical reaction without itself being changed by the reaction. The fact that they aren't changed by participating in a reaction distinguishes </span>catalysts<span> from substrates, which are the reactants on which </span>catalysts<span> work. </span>Enzymes<span> catalyze biochemical reactions.</span>
Answer:
B.
Explanation:
Bio means "life" is every part of the Earth where life is possible and exists.
