Question

Arrange the following events in protein secretion in the proper sequence.

1)The polypeptide chain enters the lumen of the endoplasmic reticulum.
2.A secretory vesicle is formed.
3.A transport vesicle is formed.
4.The polypeptide chain enters the lumen of the Golgi complex.
a) 1, 2, 3, 4
b) 2, 3, 1, 4
c) 3, 1, 2, 4
d) 1, 3, 4, 2

Answer 1

The correct arrangement of events in protein secretion sequence is: the polypeptide enters the ER, a transport vesicle is formed, the polypeptide enters the Golgi apparatus, and finally a secretory vesicle is formed to release the protein.

Step-by-step explanation:

The correct sequence of events in protein secretion is the following:

1. The polypeptide chain enters the lumen of the endoplasmic reticulum (ER).
2. A transport vesicle is formed.
3. The polypeptide chain enters the lumen of the Golgi complex.
4. A secretory vesicle is formed.

After the synthesis and entry of the polypeptide into the ER, the protein undergoes modifications such as folding. The transport vesicle, containing the modified protein, buds off from the ER and travels to the Golgi apparatus. Here it fuses and the protein enters the Golgi complex where further processing occurs.

Finally, the mature protein is packaged into a secretory vesicle that buds from the Golgi's trans face, which can then fuse with the plasma membrane to release the protein outside the cell.