Question

The various parts of the endomembrane system serve different functions in the cell. In this activity, you will identify the roles of each part of the endomembrane system Drag each function to the appropriate bin. View Available Hint(s) Reset Help protein synthesis protein modification and sorting macromolecule digestionlipid synthesis autophagy cisternal maturation calcium ion storagepoison detoxification smooth ER rough ER Golgi apparatus ysosomes
Sites of protein synthesis All proteins are synthesized by ribosomes in the cell. Some ribosomes float freely in the cytosol, while others are bound to the surface of the endoplasmic reticulum. Most proteins made by free ribosomes function in the cytosol. Proteins made by bound ribosomes either function within the endomembrane system or pass through it and are secreted from the cell. Which of the following proteins are synthesized by bound ribosomes?
a) actin
b) lysosomal enzyme
c) insulin
d) ER protein
e) DNA polymerase
f) ribosomal protein

Answer 1

Answer:

B.lysosomal enzyme

C. insulin

d. ER protein

Explanation:

Most proteins those that function in the cytosol (actin) or in the nucleus (DNA polymerase) are synthesized by free ribosomes.

Proteins that function within the endomembrane system, like in ER, Golgi complex etc (for example, lysosomal enzymes) or those that are destined for secretion from the cell (such as insulin) are synthesized by bound ribosomes. These proteins pass through  endomembrane system.

Protein those destined for the endomembrane system, are  synthesized by ribosomes,  they have signal in the growing polypeptide chain  that act as a signal sequence.