The thickness of the uterine lining , becomes very thick...because when the level of hormone progesterone reaches its highest levels. according to Dr.X on yahoo answers.
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* Channel proteins- these are proteins with a hydrophilic pore where specific ions are able to pass through the membrane. Each channel protein is specific to an ion. This is the only way ions can travel through the membrane. They are trans membrane proteins.
* Carrier proteins- these are proteins which allow larger or polar molecules through the membrane. They are trans membrane proteins.
Carrier proteins essentially “carry" signals that are not soluble in aqueous solution through the blood stream to their target cells. Carrier proteins for hydrophilic signals prevent degradation of the signal. Channel proteins are embedded in cell membranes. They often are receptors (though not always), and when activated, allow specific ions to pass through the membrane.
A channel protein is a special arrangement of amino acids which embeds in the cell membrane, providing a hydrophilic passageway for water and small, polar ions. Like all transport proteins, each channel protein has a size and shape which excludes all but the most specific molecules
The carrier protein facilitate diffusion of molecules across the cell membrane. The protein is imbedded in the cell membrane and covers the entire membrane. This is important because the carrier must transport the molecule in and out of the cell.
Transform boundary – this type of fault is found where two tectonic plates are moving alongside and parallel to each other mostly in opposite directions. This type of fault is also responsible for the rift valley and block mountains. No crust is destroyed nor new crust formed.
Convergent boundary – At this point, two tectonic plates are colliding because they are moving in opposite directions at each other. The pressure and stress of the collision force causes the plates to begin crumpling and folding at the boundary forming features such as fold mountains (an example is the Himalayas).
Convergent boundary – At this boundary , the denser of the two colliding tectonic plates (usually the oceanic plate) is subsided by the less dense one (usually the continental plate). The plate being subsided begins to melt as it does down into the mantle and becomes liquid rock. This magma rises through the fissures formed at the boundary and erupts into volcanic islands along the boundary.
