Concept 6.4: The endomembrane system regulates protein traffic and performs metabolic functions

Flashcards from Concept 6.4 of Pearson's Campbell Biology, Twelfth Edition.

Endomembrane system

System that consists of the:

• Nuclear envelope

• Endoplasmic reticulum

• Golgi apparatus

• Lysosomes

• Vacuoles

• Plasma membrane

Endoplasmic reticulum (ER)

Organelle that accounts for more than half of the total membrane in many eukaryotic cells

• Continuous with the nuclear envelope

• Divided into smooth and rough ER based on ribosomal presence

Smooth endoplasmic reticulum (smooth ER)

Endoplasmic reticulum section that

• does not have ribosomes

• synthesizes lipids

• detoxifies drugs and poisons

• stores calcium ions

Rough endoplasmic reticulum (rough ER)

Endoplasmic reticulum section that

• has bound ribosomes, secreting glycoproteins

• distributes transport vesicles

• creates membrane for the cell

Transport vesicles

Secretory proteins surrounded by membranes

Golgi apparatus

Flattened membranous sacs called cisternae

• modifies products of the endoplasmic reticulum

• makes certain molecules

• sorts and packages materials into transport vesicles

Lysosome

A membranous sac of hydrolytic enzymes that can digest (break down) macromolecules

• Has an acidic environment to support lysosomal enzymes

Phagocytosis

Engulfing another cell for food, creating a food vacuole that is digested by lysosomes

Autophagy

The process in which lysosomes recycle the cell’s own organelles and macromolecules

Vacuoles

Large vesicles derived from the ER and Golgi apparatus

Central vacuoles

Vacuoles found in mature plant cells that contain a solution called sap

• Serves as the plant cell’s main repository of inorganic ions, including potassium and chloride