approximately 115 days
Human red blood cells (RBC), after differentiating from erythroblasts in the bone marrow, are released into the blood and survive in the circulation for approximately 115 days.
I believe the correct answer is C. Nektons include bony fish and squid.
Answer:
b. a single temporal fenestra
Explanation:
Synapsids have a temporary fossa in the lower part of the temporal bone. These reptiles mamiferoides only have a single inferior temporal fenestra.
The synapsids were the first amniots to diversify and appeared in the middle of the Carboniferous. These first synapses were characterized by the presence of a single temporary fenestra behind each orbit, through which the mandibular muscles pass.
* 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.
