Answer:
The two main reasons are nonpolar core of the bilayer and the active transport.
Explanation:
The membrane is structured to have two outer layers that are polar and an inner layer that is nonpolar.
If a membrane protein is exposed to the solvent, i<em>t will also have a polar side. It would be very difficult for the polar face of the membrane to move through the nonpolar core of the bilayer.</em> Therefore, this model is not feasible.
One major form of transport, active transport, moves solutes up the concentration gradient. <em>The binding of a solute and then release on another side of the membrane would only work for facilitated diffusion because it would cause a net movement of solutes down the concentration gradient.</em> It is unclear how energy could be expended to drive this process in the transverse carrier model.<em> Therefore, the transverse carrier model does not explain active transport.</em>
Answer:
Cyclin-regulates the timing of the cell cycle. Normally, when cells touch, they stop growing. Growth factors-one of a group of external regulatory proteins that stimulate the growth and division of cells.
Explanation:
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Answer:
335 million years ago
Explanation:
Pangaea or Pangea ( /pænˈdʒiːə/) was a supercontinent that existed during the late Paleozoic and early Mesozoic eras. It assembled from earlier continental units approximately 335 million years ago, and began to break apart about 175 million years ago.
... termed "hypotonic," meaning less solids (or more diluted) than inside the cell. For fluid movement in/out of cells, water will diffuse (via osmosis) from the hypotonic solution to the hypertonic one, assuming a permeable barrier (i.e. cell membrane) allows it. With this case, water will flow into the cell from outside.
One factor is resting and exercising
stress and peace