Endomembrane system

Definition

The endomembrane system is a group of organelles in eukaryotic cells that work together to modify, package, and transport lipids and proteins. Key components include the endoplasmic reticulum, Golgi apparatus, lysosomes, and vesicles.

5 Must Know Facts For Your Next Test

1. The endomembrane system helps compartmentalize the cell, creating specific environments for different biochemical reactions.
2. The rough endoplasmic reticulum (RER) is studded with ribosomes and is involved in protein synthesis.
3. The smooth endoplasmic reticulum (SER) lacks ribosomes and is involved in lipid synthesis and detoxification processes.
4. The Golgi apparatus modifies proteins and lipids received from the ER and sorts them for transport to their final destinations.
5. Lysosomes contain digestive enzymes that break down waste materials and cellular debris.

Review Questions

• What are the main functions of the endomembrane system?
• How do the rough ER and smooth ER differ in structure and function?
• What role does the Golgi apparatus play in protein modification?

Related terms

Endoplasmic Reticulum:

A network of membranous tubules within the cytoplasm of a eukaryotic cell, continuous with the nuclear membrane.

Golgi Apparatus:

A series of stacked membranes that modifies, sorts, and packages proteins for secretion or delivery to other organelles.

Lysosome: A membrane-bound organelle containing enzymes that break down biological polymers such as proteins, lipids, nucleic acids, and carbohydrates.