Table 1.
Major subcellular compartments |
Major biological function |
Morphological features |
Physiological features | General mechanisms of accumulation |
---|---|---|---|---|
Lysosomes & endosomes |
Degradation of excessive cellular proteins, lipids and organelles |
Membrane-bound, vesicles |
Acidic luminal environment (pH<6) Contain unique, lysosomal protease and hydrolyses. |
Active transport; ion trapping; interaction with organelle resident proteins; receptor endocytosis; fluid phase pinocytosis; intracellular membrane trafficking. |
Mitochondria | Energy conversion and storage of calcium ions |
Membrane-bound, with internal membrane structure |
Negative membrane potential. Weakly basic luminal pH (~8). Two membranes. Contain DNA. |
Active transport; trapping by chemoelectrical potential; interaction with mtDNA andorganelle resident proteins |
Nucleus | Storage of genetic materials |
Membrane-bound with large protein pores |
Composed of phosphate-rich DNA, RNA, and a large variety of proteins |
Active transport; partitioning to nuclear envelope; interaction with DNA, RNA (nucleolar) and organelle resident proteins |
Plasma membrane |
Separation of the cytosol form the outside environment |
Membrane protein-rich phospholipid bilayer membrane |
Fluid mosaic, lipid bilayer with selective permeability. |
Lipophilic partitioning; absorption to phospholipids; interaction with membrane proteins |
Endoplasm reticulum |
Facilitation of protein folding and transport of synthesized proteins |
Interconnected network of membrane tubules. |
Intracellular membrane trafficking; interaction with phospholipids or organelle resident proteins |
|
Golgi apparatus |
Process and package of macromolecules |
Stacks of semicircular or planar membrane-bound compartments |
Intracellular membrane trafficking; interaction with phospholipids or organelle resident proteins |
|
Cytosol | Intracellular solution-like matrix |
Interaction with cytosolic components such as the cytoskeleton |