Which mechanism best describes the process by which nutrients are taken up at the apical surface of the epithelial cells that line the guy and released from their basal and lateral surfaces? a. Proteins are tethered to the cell cortex
b. Proteins are tethered to the extracellular matrix
c. Protista are tethered to the proteins on the surface of another cell
d. Protein movement is limited by the presence of a diffusion barrier

The correct answer is option d. "Protein movement is limited by the presence of a diffusion barrier".

Explanation:

There are transportation mechanisms that allow to take up nutrients to the apical surface of the epithelial cells. The transportation process is best describes as protein movement limited by the presence of a diffusion barrier. There are structures known as tight junctions, located just below the apical surface . These tight junctions acts as diffusion barriers, separating the  extracellular fluids surrounding the apical and basolateral membranes.

step 1 ammonium can be absorbed by plants, but some is converted into nitrates which are better for plants to absorb. this is called nitrification. 2. step 2 the deer eats the plants and uses the nitrogen-containing proteins for cell growth. 3. step 3 bacteria in the soil conduct nitrogen fixation to convert nitrogen gas from the atmosphere into ammonium. 4. step 4 some of the nitrates are absorbed back into plants, but denitrification breaks down the nitrates into nitrogen gas released back into the atmosphere. 5. step 5 nitrogen is found in the urine, which gets broken down into ammonium through the process of ammonification. 6. step 6 plants absorb the ammonium and begin assimilation, the process to add the nitrogen to protein.

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