Lecture 5 Mar. 15/12
Intracellular Compartments and Protein Sorting
Intracellular compartments
Cytosol
•Half of cell volume
•Degradation and synthesis of proteins, small molecules for metabolism
•Not an organelle
Organelles
•Subcellular component with distinct function, usually membrane enclosed
•Lysosome/vacuole (in plants): digestive enzyme
•Golgi apparatus: modifies proteins and lipids
•Mitochondrion: used for ATP synthesis
•Nucleus: DNA/RNA synthesis
•RER (rough endoplasmic reticulum): synthesis of various proteins
•SER (smooth): phospholipid synthesis, detoxification
•Endosome: endocytosis, absorbs other molecules by engulfing them
•Peroxisome: used in various oxidative reactions
Non-organelles
•Polyribosomes: used for protein synthesis
Endomembrane system
•Composed of endosome, peroxisome, ERs, Golgi apparatus, lysosome/vacuole
•Involved in two main pathways:
1) Biosynthetic/secretory pathway
oProteins and lipid made in ER (biosynthesis)
oDelivered to other organelles (bio)
oHelps secreted proteins move out of the cell through exocytosis (secretion)
2) Endocytic Pathway
1