Tiny spherical bodies composed of RNA and protein

Actual sites of protein synthesis

Floating free or attached to a membrane structure in the cytoplasm

Membranous system of tubules that extends throughout the cytoplasm.

Rough ER is studded with ribosomes.

Smooth ER is the site of steroid and lipid synthesis, lipid metabolism and drug detoxification.

Stack of flattened sacs with bulbous ends and associated small vesicles

Found close to the nucleus

Packages protein and other substances for export from the cell into plasma membrane

Packaging lysosomal enzymes

Various sized membranous sacs containing digestive enzymes

Function to digest worn-out cell organelles and foreign substances that enter the cell

Have the capacity of total cell destruction if ruptured

Generally rod-shaped bodies with a double-membrane wall

Inner membrane is thrown into folds, or cristae

Contain enzymes that oxidize foodstuffs to produce cellular energy (ATP)

Often referred to as "powerhouse of the cell"

Paired, cylindrical bodies lie at right angles to each other, close to the nucleus

Direct the formation of the mitotic spindle during cell division

Form the bases of cilia and flagella

Cytoskeletal elements:

microfilaments

intermediate filaments

microtubules

Provide cellular support

Function in intracellular transport

Microfilaments are important in cell mobility

Intermediate filaments are stable elements composed of protein and resist mechanical forces acting on the cell

Microtubules from the internal structure of the centrioles and help determine cell shape