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>
Nivel subatómico: lo integran las partículas más pequeñas de la materia, como son los protones, los neutrones y los electrones.
Nivel atómico: lo componen los átomos, que son la parte más pequeña de un elemento químico que puede intervenir en una reacción.
Nivel molecular: está formado por las moléculas, que se definen como unidades materiales formadas por la unión, mediante enlaces químicos, de dos o más átomos, como por ejemplo una molécula de oxígeno (O2) o de carbonato cálcico (CaCO3).
Espero te sirva
Answer:
The force of surface tension in the lungs is so great that without something to reduce the surface tension, the airways would collapse after exhalation, making re-inflation during inhalation much more difficult and less effective. Collapse of the lungs is called alectasis.
Explanation:
It totally depends upon whether modification is being done in somatic cells or germ cells. Somatic cells modification is ethically accepted because it doesn't pass from one generation to another generation but germline modification is considered as unethical because the modification will pass on to the next generation leading to the persistence of modification in future generations. The problem with genetic modifications is that the impacts of modifications are unpredictable, rather than being fruitful they may lead to lethal mutations so if it occurs in just somatic cells, then even if it is lethal/harmful, it will be confined to only that individual but if a lethal mutation occurs in germ cells then it will pass on to the subsequent generations and it will persist in all future generations.
<span>a)
</span>The milkweed is the primary producer in the
ecosystem. It manufactures food from the abiotic factors in the soil such as
nitrates and water and those in the atmosphere such as carbon-dioxide and
sunlight. The milk weed is then fed on by the caterpillar and a primary
consumer. The caterpillar is then fed on the mocking bird (secondary consumer)
<span>b)
</span>Increased human population growth and their activities
have resulted in the emission of carbon dioxide and other greenhouse gases in
the atmosphere. This has increased the global temperature. This increase of
global temperature increase ocean temperatures causing coral bleaching.
Another example is depletion of water sources
by human activities hence causing drought. Drought reduces the amount of
vegetation growth due to scarcity of water in the soil (due to lowering of the
water table) for plant growth.
