Transport proteins (carrier proteins and channel proteins) allow substances into and out of the cell that cannot pass through the phospholipid bilayer (as they’re either to large, charged or not lipid soluble) by facilitated diffusion.
Specifically channel proteins allow ions into and out of the cell by creating a pore in the membrane in which they can move through with their concentration gradient
Answer:
True
Explanation:
In phase-contrast objective and a phase contrast optical systems is equipped with Light microscope .
Phase contrast microscope is used to differentiate unstained structures in a cell that differ in refractive indices and thickness. Thus it is usefull for examining living unstained organisms.
Light that passed through materials of different refractive index and/or thickness will undergo a change in Phase. The difference in phase or wave front irregularities cause variation in brightness of the structures.
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<span>One observation would be the physical size of Russia compared to other countries, despite a lack of visible borders from space. In addition, part of Russia's outline would likely be obscured by the various clouds and objects in the stratosphere; this would allow the astronaut to view potential cloud and weather patterns on earth. Also, an astronaut could see outlines of Russia's geography such as mountain ranges.</span>
