Overview of the Endomembrane System and the Golgi Apparatus

These flashcards cover essential vocabulary and concepts from the lectures on the endomembrane system and Golgi apparatus.

Cytoplasmic Membrane System

A coordinated unit formed by the ER, Golgi complex, endosomes, lysosomes, and vacuoles.

Endoplasmic Reticulum (ER)

A network of membranes in cells that plays a critical role in protein and lipid synthesis.

Transport Vesicles

Membrane-bound structures that transport materials between different compartments within the cell.

Biosynthetic Pathway

A pathway in which proteins are synthesized in the ER, modified in the Golgi, and sent to their destinations.

Secretory Pathway

The process by which proteins synthesized in the ER are secreted from the cell.

Constitutive Secretion

The continual transport of materials from the cell in secretory vesicles.

Regulated Secretion

Storage of materials in vesicles until a stimulus triggers their release.

Rough Endoplasmic Reticulum (RER)

A type of ER with ribosomes on its surface, involved in protein synthesis and processing.

Smooth Endoplasmic Reticulum (SER)

A type of ER lacking ribosomes, involved in lipid synthesis and detoxification.

Signal Sequence

A short amino acid sequence that directs the transport of proteins to specific cellular locations.

Cisternae

Flattened, membrane-bound sacs that make up the structure of the Golgi apparatus.

Golgi Apparatus

A cellular organelle that modifies, sorts, and packages proteins for secretion.

Translocon

A protein complex that facilitates the passage of proteins into the endoplasmic reticulum.

Endosome

Membrane-bound compartments that transport materials from the cell surface to lysosomes.

Lysosomes

Organelles that contain enzymes for digesting cellular waste and macromolecules.

Peroxisomes

Organelles involved in the breakdown of fatty acids and detoxification of hydrogen peroxide.

Nuclear Envelope

A double membrane structure that encloses the nucleus of eukaryotic cells.

Calcium Ion Sequestration

The process by which the smooth ER stores calcium ions for cellular signaling.

Apoptosis

Programmed cell death that can involve Golgi-derived factors.

Signal Hypothesis

The theory that proteins contain signals that dictate their cellular transport.

Reticuloplasm

The fluid within the endoplasmic reticulum lumen, distinct from cytoplasm.

Vesicles

Small membrane-bound sacs that transport substances within cells.

Glycoproteins

Proteins that have carbohydrate groups attached, often modified in the Golgi apparatus.

Tubules

Irregular branching structures that form part of the endoplasmic reticulum.

Membrane Asymmetry

The difference in composition between the inner and outer leaflets of cellular membranes.

Lipid Transfer Proteins

Proteins that facilitate the transfer of lipids between different organelle membranes.

Cytoskeleton

A network of fibers that helps maintain the shape and organization of the cell.

Mitochondria

Organelles known as the powerhouses of the cell, responsible for energy production.

Endocytic Pathway

A process that transports materials into the cell from the extracellular space.

Secretory Granules

Large vesicles that store proteins and other materials for secretion.

Organelle Formation

The creation and maintenance of cellular compartments, such as lysosomes and vacuoles.

Plasmalemma

Another term for the plasma membrane, which surrounds the cell.

Glycosylation

The addition of carbohydrate groups to proteins, a process that begins in the ER.

Protein Phosphorylation

The addition of phosphate groups to proteins, often regulating their function.

Diacyglycerol

A lipid that plays a role in cellular signaling and membrane dynamics.

Endomembrane System

A network of membranes that work together to modify, package, and transport lipids and proteins.

Endogenous Proteins

Proteins that are naturally produced within a cell.

Exocytosis

The process of exporting materials out of the cell through vesicles.

Secretion Modes

The different mechanisms cells use to transport proteins outside of their membranes.

Cytochrome P450

A family of enzymes involved in drug metabolism and detoxification processes.

Vesicular Transport

The process through which materials are shuttled in vesicles between compartments of the cell.

Cytosol

The fluid component of the cytoplasm where metabolic processes occur.

Plant Cells

Eukaryotic cells that have a cell wall, chloroplasts, and a large central vacuole.

Cellular Destinations

The specific locations within a cell where proteins and materials are delivered.

Peroxisomal Enzymes

Enzymes located in peroxisomes that are crucial for lipid metabolism.

Nissl Substance

Clumps of ribosomal RNA found in the cell bodies of neurons.

Sarcoplasmic Reticulum

A specialized form of smooth ER found in muscle cells, involved in calcium storage.

Alveolar Epithelium

The thin layer of cells lining the alveoli in the lungs where gas exchange occurs.

Desmotubules

Structural components of plasmodesmata in plant cells that connect ER between cells.

Structurally Complex Proteins

Proteins requiring co-factors or modifications to function properly.

Endoplasmic Reticulum Memory

The ability of the ER to modify proteins based on their previous processing experiences.