Organelles
All the organelles are contained within the cytoplasm, which comprises an aqueous solution of the
molecules synthesized and utilized by the cell, i.e. soluble enzymes, vitamins, amino acids,
carbohydrates, lipids and other material. The cytoplasm is enclosed in the cytoplasmic membrane,
which comprises primarily phospholipids and proteins and is the effective boundary between the
cell and its environment. It is the function of the cytoplasmic membrane to transport molecules into
and out of the cell with the aid of specific transport proteins. For locomotion, eukaryotic microbes
generally employ either a single flagellum or a small number of flagella, although one important
group employs cilia.