ENDOMEMBRANE SYSTEM

ENDOMEMBRANE SYSTEM

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The Endomembrane System

• The endomembrane system consists of:

• Nuclear envelope• Endoplasmic reticulum• Golgi apparatus

• Vesicles• Plasma Membrane

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Nucleus and nuclear envelope

ENDOMEMBRANE SYSTEM

Endomembrane system, I -ER• Continuous with

nuclear envelope

TWO TYPES• Smooth ER• Rough ER

Smooth Endoplasmic Reticulum

Smooth ER• Lacks significant number of

ribosomes on external surface.Functions:• Makes lipids, phospholipids,

and steroids.• Detoxifies poisons and toxins• Stores Ca+2 in muscle cells• Metabolism of Carbohydrates• Produce vesicles which

contain newly produced proteins.

Rough Endoplasmic Reticulum

• Cytoplasmic side is covered with ribosomes• Further manufactures and processes proteins from

ribosomes destined to become secretory proteins (enzymes, hormones).

• Makes phospholipids and embeds proteins in them: making new cell membrane.

ENDOMEMBRANE SYSTEM

Endomembrane system, II - Golgi

• ER products are modified, stored, and then shipped

• Made of flattened saccules (cristernae) of membrane.

• cis face (receiving) & trans face (shipping)

• Creating vesicles

Golgi Apparatus

Golgi Apparatus – “Post Office”

Export products Of Golgi Apparatus have three possible fates:

1. To extracellular environment.2. Vesicles converted into:

Lysosome which stores hydrolytic enzymes. Used to attack pathogen or break down dead or damaged cell. Cell recycler of the cell’s own organic material.Peroxisomes which store enzymes involved in peroxide metabolism.

3. Add more plasma membrane to the cell to facilitate growth.

LYSOSOMES AND PEROXISOMES

ENDOMEMBRANE SYSTEM

The Cell Membrane• “The gatekeeper of

the cell”• A thin, outer

covering of the cell.

• Controls what goes in and out of cell.

EXOCYTOSIS

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DRAMA TIMEEndomembrane System

FEATURING:

• Nuclear envelope• Endoplasmic reticulum• Golgi apparatus

• Vesicles• Plasma Membrane