The Endomembrane System

Flashcards covering key concepts from the lecture on the endomembrane system, including the roles of different organelles, protein synthesis, and glycosylation.

What is the primary role of the endomembrane system?

The endomembrane system plays a role in compartmentalizing function within organelles and regulating trafficking of lipids and proteins between them.

Which organelle is involved in the sorting and processing of proteins and lipids received from the ER?

The Golgi apparatus.

What are the two main types of endoplasmic reticulum?

Rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER).

What is the function of lysosomes?

Lysosomes digest ingested material and unneeded cellular components.

What is the smooth endoplasmic reticulum primarily involved in?

Lipid synthesis, drug detoxification, carbohydrate metabolism, and calcium storage.

Define glycosylation.

The addition of carbohydrate side chains to proteins.

How do proteins enter the endoplasmic reticulum?

Proteins enter the ER while being synthesized.

What is the role of the signal-recognition particle (SRP) in protein synthesis?

SRP binds to the ribosome and the ER signal sequence as it leaves the ribosome, guiding it to the ER.

What is the difference between N-linked and O-linked glycosylation?

N-linked glycosylation adds oligosaccharides to nitrogen atoms of asparagine residues, while O-linked glycosylation adds them to oxygen atoms on hydroxyl groups of serine or threonine residues.

What happens to improperly folded proteins in the ER?

They are bound by the glucosyl transferase UGGT and are kept for further processing until proper conformation is achieved.