Endomembrane System

Eukaryotic Cells

Cells that contain a nucleus and membrane-bound organelles, evolved from prokaryotic cells.

Prokaryotic Cells

Unicellular organisms without a nucleus or membrane-bound organelles, including domains Bacteria and Archaea.

Infolding Theory

Postulates that parts of the prokaryotic plasma membrane folded inward, forming compartments that evolved into organelles.

Endosymbiotic Theory

Explains that mitochondria and chloroplasts originated when a larger prokaryotic cell engulfed smaller prokaryotes, forming a symbiotic relationship.

Endomembrane System

A network of interconnected organelles responsible for the synthesis, modification, transport, and export of proteins and lipids.

Rough Endoplasmic Reticulum (Rough ER)

An organelle with ribosomes attached that synthesizes proteins and packages them into vesicles.

Golgi Apparatus

Organizes, modifies, and packages proteins received from the rough ER for transport.

Exocytosis

The process through which vesicles fuse with the plasma membrane to export proteins outside the cell.

Smooth Endoplasmic Reticulum (Smooth ER)

Organelle involved in lipid synthesis and detoxification, lacking ribosomes.

Lysosomes

Specialized vesicles containing enzymes that break down macromolecules and damaged organelles.

Peroxisomes

Vesicles responsible for detoxifying harmful byproducts like hydrogen peroxide.

Vacuoles

Storage organelles in plant cells that hold water and nutrients, crucial for turgor pressure.

Nucleus

The organelle that stores genetic information, protected by a double phospholipid bilayer nuclear envelope.

Cytoskeleton

A network of protein filaments that provides structure and facilitates vesicle transport within the cell.

Phospholipid Bilayer

The fundamental structure of most cellular membranes, consisting of two layers of phospholipids.

Double Membrane

A feature of mitochondria and chloroplasts indicating their evolutionary origin from engulfed prokaryotes.

Cellular Symbiosis

A mode of interaction between organisms (e.g., mutualism, commensalism, parasitism) that helps explain endosymbiosis.

Mutualism

A type of symbiosis where both organisms benefit from the interaction.

Exocytosis and Endocytosis

Processes that allow for the bidirectional flow of cargo into and out of cells via the endomembrane system.

Intracellular Transport

The movement of vesicles carrying proteins and lipids between organelles.