<span>Tight junctions, at the site of a tight junction, cells are held tightly against each other by many individual groups of tight junction proteins called claudins, each of which interacts with a partner group on the opposite cell membrane. For example, the tight junctions between the epithelial cells lining your bladder prevent urine from leaking out into the extracellular space.</span>
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: Low oxygen content.
Explanation:
There are many dangers to the survival of fish in shallow water that depend on the properties of water.
1. The oxygen content drops during the winter and also in hot weather. Fish cannot survive without enough oxygen in the water.
2. High evaporation rates can drain the pond.
3. Fortunately, water has a high thermal mass, so overheating the water to the boiling point is not an issue.
Of the three reasons given, lack of oxygen is the most critical.
Answer: mRNA: GCU : alanine
Explanation:
"The density of a substance determines how much light is refracted"
Hope this helps :)
