Composed of RNA and protein. Actual sites of protein synthesis. Synthesize proteins for: 1. use in the cell (free ribosomes) 2. secretion, incorporation into plasma membrane, or lysosomes (fixed ribosomes)
Composed of microfilaments, intermediate filaments and microtubules. Provides structural support; facilitates cytoplasmic streaming, organelle and cellular motility, transport of materials, and chromosomal movement in cell division.