Video summary

Practically's Concepts - Golgi Apparatus - #LearnPractically

Main summary

Key takeaways

Educational

Main ideas / concepts about the Golgi apparatus

Discovery

The Golgi apparatus was first discovered in 1898 by the Italian cytologist Camilo Golgi in the nerve cells of an owl.

Alternative names

It is also called:

  • Lipochondria
  • Idiosome
  • Dalton complex
  • Baker’s body

Where it is found

The Golgi apparatus is present in all eukaryotic cells, except:

  • Mature sieve elements in plants
  • Mature sperm cells in animals
  • RBC (red blood cells) in animals

Biogenesis / formation (how it develops)

The Golgi apparatus develops from:

  • Invaginations of the plasma membrane
  • Evagination of the nuclear membrane
  • Endoplasmic reticulum (ER)

Components of the Golgi complex

The Golgi complex contains four main components:

  1. Cisternae
  2. Tubules
  3. Vesicles
  4. Golgi vacuoles

Cis face vs trans face (polarization and flow)

The Golgi complex is a polarized organelle.

  • Forming face / cis face (convex cis face) Receives vesicles from the endoplasmic reticulum (ER).

  • Maturing face / trans face (concave trans face)

    • Normally oriented toward the plasma membrane
    • Releases contents in the form of Golgi vacuoles/cisternae

  • Interconnection The cis and trans faces are different but interconnected.

Cisternae details

  • Cisternae are flat, disc-shaped sacks with swollen ends.
  • They are curved and parallelly arranged, with smooth membrane sacs.
  • Many cisternae are often:
    • Concentrically arranged near the nucleus
  • Diameter of each cisterna: ~0.5 to 1 micrometers
  • Their curvature contributes to the organelle’s polarity.

Tubules

  • Tubules are short, branched, interconnected filamentous structures.
  • They develop:
    • on the sides of cisternae
    • and also at the maturing face

Vesicles

Vesicles are small sacs that develop from tubules. Two types:

  • Smooth vesicles
    • Smooth surfaced secretory vesicles
    • Contain secretory granules
  • Coated vesicles
    • Rough surfaced
    • Covered with fine bristle-like outgrowths

Golgi vacuoles

  • Golgi vacuoles are large, rounded sacs.
  • They are produced by the concave surface of the Golgi apparatus.
  • Some Golgi vacuoles function as lysosomes, filled with granular substances.

Functions / key roles of the Golgi apparatus

  • Packaging and delivery

    • The Golgi apparatus packages materials for:
      • intracellular targets, or
      • secretion outside the cell

  • Movement and fusion pathway

    • Materials come from the ER in vesicles
    • Vesicles fuse with the cis face of the Golgi apparatus
    • Contents then move toward the trans face
    • This explains why the Golgi complex stays closely associated with the ER

  • Modification before release

    • Proteins synthesized on ribosomes on the ER are modified in the cisternae of the Golgi apparatus before being released from the trans face

  • Biochemical synthesis

    • Important site for formation of:
      • Glycoproteins
      • Glycolipids

  • Cell structure formation

    • Helps in formation of root hairs from root epidermal cells

  • Animal reproduction

    • The acrosome of the animal sperm cell is synthesized by the Golgi apparatus

Speakers / sources featured

  • No speakers are indicated in the subtitles.
  • Source named: Camilo Golgi (credited with discovery in 1898)

Original video