Tracking a protein through a cell

Organelles that Build Proteins

• Ribosomes, Endoplasmic Reticulum, Golgi Apparatus

• One of the most important jobs of the cell is making proteins

• Proteins are assembled on the ribosomes• Ribosomes are small particles of RNA and

proteins that produce other proteins using the coded instructions from DNA

• Ribosomes are assembled in the nucleolus

nucleusnucleolus

ribosomes

Endoplasmic Reticulum

Rough endoplasmic reticulum

Smooth endoplasmic reticulum

Proteins targeted for export to the cell membrane or to special locations such as lysosomes complete their assembly on ribosomes attached to the rough ER

Proteins targeted for export to the cell membrane or to special locations such as lysosomes complete their assembly on ribosomes attached to the rough ER

The smooth ER contains enzymes that synthesize membrane lipids and detoxification materials found in liver cells

Free ribosomes

Other cellular proteins are made on ribosomes which are not attached to ER

Golgi apparatus

Newly assembled proteins are carried from the rough ER to the golgi apparatus vesicles

The golgi apparatus modifies, sorts, and packages proteins and other materials for storage in the cell or transport out of the cell

It also ships proteins to their final destination

Ribosome

Large subunit

Small subunit