Question

What do COP-I coated vesicles do?

A) Transport materials from Golgi to the endoplasmic reticulum
B) Transport materials from the endoplasmic reticulum to the Golgi
C) Facilitate endocytosis
D) Mediate transport between the Golgi cisternae

Answer 1

COP-I coated vesicles play a key role in retrograde transport, moving materials from later Golgi compartments to earlier ones. This process is vital for maintaining the organization and functionality of the Golgi apparatus,So, the correct option is D.

Explanation:

COP-I coated vesicles play a crucial role in mediating the transport of materials between the Golgi cisternae. The term COP-I stands for Coatomer Protein I, and these vesicles are coated with coatomer proteins that facilitate the budding of vesicles from the membranes of the Golgi apparatus.

This process is essential for maintaining the organization and functionality of the Golgi apparatus. The specificity of COP-I coated vesicles in mediating intra-Golgi transport is vital for ensuring that proteins and lipids are correctly sorted and transported between different cisternae of the Golgi apparatus.

These vesicles function in retrograde transport, meaning they move materials from later compartments of the Golgi back to earlier ones. This retrograde transport is crucial for maintaining the composition and integrity of the Golgi apparatus, allowing it to perform its role in modifying and sorting proteins. The coatomer proteins recognize specific sorting signals on the membranes of Golgi compartments, ensuring the selective packaging of materials into COP-I coated vesicles. This process is finely regulated and contributes to the overall efficiency of intracellular transport within the cell.

In summary, COP-I coated vesicles facilitate the retrograde transport of materials within the Golgi apparatus, mediating the transport between different cisternae. This process is fundamental for the proper functioning of the Golgi apparatus and ensures the correct sorting and modification of proteins and lipids within the cell,Thus, the correct option is D.

Answer 2

COP-I coated vesicles transport materials from the Golgi apparatus back to the ER. They are involved in the recycling of proteins and help maintain the endomembrane system by retrieving ER-resident proteins from the Golgi.

So, the correct option is D.

Step-by-step explanation:

COP-I coated vesicles are involved in the retrograde transport of materials from the Golgi apparatus back to the endoplasmic reticulum (ER). When proteins and lipids bud from the endoplasmic reticulum in vesicles, they are initially coated with COPI or COPII proteins.

The vesicles then travel to the cis face of the Golgi apparatus, where they fuse and empty their contents for processing. As proteins and lipids pass through the Golgi stack, they undergo modifications, including glycosylation.

Finally, the COP-I coated vesicles facilitate the recycling of proteins and retrieval of ER-resident proteins from the Golgi back to the ER, maintaining the proper functioning and organization of the cell's endomembrane system.

So, the correct option is D.