Penetration of the egg' zona pellucida by the sperm cell is a process driven by hydrolytic enzymes.
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The critical step in fertilization is binding between sperm receptors and glycoproteins on the zona pellucida. This is the trigger for the acrosome reaction which includes an influx of CA and a rise in pH and cAMP levels within the sperm head. As a result, the plasma membrane of the sperm fuses with the outer acrosomal membrane and the exocytosis of the acrosomal<span> vesicle occurs. Components of the acrosome, like hydrolytic enzymes, are released and they degrade the <span>zona pellucida allowing</span> the sperm to move </span>inside.</span>
Fires disrupt the equilibrium of an ecosystem. The results of a fire include a resetting of plant succession. Many ecosystems have adapted to a certain frequency and intensity of wildfires, and many plant species actually require fires as part of their life cycles. Fires can open up forests and grasslands that would be too congested and shaded to allow young grasses or trees to take root. Fires in fact act as a stimulus for some seeds to germinate. These would typically be pioneer plants that are able to grow in fairly harsh and varied conditions. Fires also remove accumulated dead tree matter that can accumulate in a forest, and if wildfires are too infrequent, fires and be very intense when they do happen as they are fed by the accumulated material.
Before mitosis, the cell creates an identical set of its own genetic information – this is called DNA replication. The genetic information is in the DNA of the chromosomes. At the beginning of mitosis the chromosomes wind up into visible objects that can be seen with a light microscope. The chromosomes are now two chromatids joined at the centromere. Since the two chromatids are identical to each other, they are called sister chromatids.
Mitosis happens in all types of dividing cells in the human body except with sperm and ova. The sperm and ova are gametes or sex cells. The gametes are produced by a different division method called meiosis.
Answer:
An independent variable is the variable that is changed or controlled in a scientific experiment to test the effects on the dependent variable. A dependent variable is the variable being tested and measured in a scientific experiment.
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Answer:
D) Crossing an iguana with webbed feet with one with no webbing would produce iguanas ALL with no webbing because this is the dominant trait.
Explanation:
I just did the usatestprep and got it right ;)
