Answer:
Pepsinogen is produced by chief cells and is activated by hydrochloric acid secreted by parietal cells.
Explanation:
Pepsinogen is a proenzyme produced in the chief cells (that are located in the stomach lining) that, when gets activated, is transformed into pepsin - a peptidase with the function to degrade proteins into amino acids.
The reason why pepsinogen is released inactive is that it would break down all of the cell's proteins because of its proteolytic nature. For this reason, it is released as a proenzyme and gets activated when reaches the acidic environment provided by the hydrochloric acid secreted by the parietal cells, also in the stomach lining.
You can recognize the process of pinocytosis when THE CELL IS ENGULFING EXTRACELLULAR FLUID.
Pinocytosis is one of the forms of endocytosis; it involves the movement of large particle into the cell by an in-folding of the plasma membrane. It is an active form of transport used to move materials into the cells.
The answer is cell. In the cell level of organization arachnoidiscus enhrenbergii and the stomach can be seen.
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