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Endomembrane System Video

Sep 16, 2025

Overview

  • The endomembrane system is a group of organelles in eukaryotic cells that work together to create, modify, and transport proteins and lipids.

Main Components

  • Nuclear envelope
  • Rough endoplasmic reticulum (ER): has ribosomes; makes proteins.
  • Smooth endoplasmic reticulum (ER): no ribosomes; detoxifies chemicals and makes lipids.
  • Golgi apparatus: sorts, packages, and distributes cell products.
  • Vesicles: transport materials between organelles and to the cell surface.

Endoplasmic Reticulum (ER)

  • Rough ER:
    • Covered with ribosomes, giving it a "rough" appearance.
    • Produces proteins, which are packaged into transport vesicles and sent to the Golgi apparatus.
  • Smooth ER:
    • Lacks ribosomes, giving it a smooth look.
    • Detoxifies harmful chemicals and produces lipids.
    • Lipids are packaged into vesicles and sent to the Golgi apparatus.

Golgi Apparatus & Vesicle Transport

  • The Golgi apparatus is a stack of flattened sacs, like pancakes.
  • Acts as the cell’s “post office”—receives, modifies, and sorts proteins and lipids.
  • Some proteins from the rough ER are changed into digestive enzymes and packed into lysosomes.
  • Lysosomes fuse with incoming vesicles and use enzymes to break down contents, releasing nutrients.
  • Other products are packed into secretory vesicles, which merge with the plasma membrane to release contents outside the cell.

Specialization & Cell Differences

  • The endomembrane system can be adjusted for different cell needs:
    • Muscle cells: have more rough ER for protein production.
    • Liver cells: have more smooth ER for detoxification.
  • The basic process of moving materials is similar in all eukaryotic cells.

Key Terms

  • Endomembrane System: group of organelles for making and moving proteins and lipids.
  • Endoplasmic Reticulum (ER): rough (protein production) and smooth (lipid production, detoxification).
  • Ribosome: makes proteins on rough ER.
  • Golgi Apparatus: packages and ships cell products.
  • Vesicle: small sac that transports materials.
  • Lysosome: vesicle with enzymes for breaking down materials.
  • Secretory Vesicle: releases products outside the cell.

Must Remember

  • The endomembrane system includes the nuclear envelope, rough and smooth ER, Golgi apparatus, and vesicles.
  • Rough ER: makes proteins.
  • Smooth ER: detoxifies chemicals and makes lipids.
  • Golgi apparatus: changes, sorts, and ships cell products.
  • Lysosomes: break down materials and release nutrients.
  • Secretory vesicles: send products out of the cell.
  • The system can change to fit what a cell needs, but the basic steps are the same in all eukaryotic cells.

Quick Review / Next Steps

  • Know the function of each part: nuclear envelope, rough ER, smooth ER, Golgi apparatus, vesicles, lysosomes, and secretory vesicles.
  • Be able to trace the path of a protein from rough ER to Golgi to its final destination.
  • Understand the roles of transport vesicles, lysosomes, and secretory vesicles.
  • Give examples of how the system adapts in different cell types.
  • Summarize how the endomembrane system works together to move and modify proteins and lipids.

Full transcript