Cell Biology Text

Schematic of Typical Animal Cell, Showing Subcellular Components

1. Nucleolus  8. Smooth Endoplasmic Reticulum
2. Nucleus  9. Mitochondria
3. Ribosome  10.Vacuole
4. Vesicle  11.Cytoplasm
5. Rough Endoplasmic Reticulum  12.Lysosome
6. Golgi Apparatus  13.Centrioles
7. Cytoskeleton    


Nucleus a membrane-enclosed organelle that is the control center of the cell and contains the cell's genetic material which is organized as multiple long linear DNA molecules in complex with a large variety of proteins, such as histones, to form chromosomes.
Mitochondrion a membrane-enclosed organelle, often called the "cellular power plant". Mitochondria generate most of the cells' supply of adenosine triphosphate (ATP), the body's main source of energy.
Lysosome organelles that contain digestive enzymes (acid hydrolases). They digest excess or worn-out organelles, food particles, and engulfed viruses or bacteria.
Vesicle a relatively small intracellular, membrane-enclosed sac that stores or transports substances.
Golgi apparatus an organelle that processes and packages macromolecules such as proteins and lipids after their synthesis and before they make their way to their destination; it is particularly important in the processing of proteins for secretion. It forms a part of the cellular endomembrane system.
Endoplasmic reticulum an organelle composed of an interconnected network of tubules, vesicles and cisternae.
Smooth endoplasmic reticulum sections of endoplasmic reticulum which are not studded with ribosomes and are connected to the nuclear envelope. It functions in several metabolic processes, including synthesis of lipids, metabolism of carbohydrates and calcium concentration, drug detoxification, and attachment of receptors on cell membrane proteins.
Rough endoplasmic reticulum sections of the endoplasmic reticulum which are studded with protein-manufacturing ribosomes giving it a "rough" appearance (hence its name). Its primary function is the synthesis of enzymes and other proteins.
Vacuole membrane-bound compartments within some eukaryotic cells that can serve a variety of secretory, excretory, and storage functions.
Nucleolus a roughly spherical sub-organelle of the cell nucleus. Its main function is to produce and assemble ribosome components (i.e. RNA, proteins).
Ribosome complexes of RNA and protein that are found in all cells. Ribosomes build proteins from the genetic instructions held within messenger RNA.
Centrosome the main microtubule organizing center of cells as well as a regulator of cell-cycle progression.



Cell membrane (also called the plasma membrane, plasmalemma or "phospholipid bilayer") is a semipermeable lipid bilayer found in all cells; it contains a wide array of functional macromolecules.
Cytoskeleton a cellular "scaffolding" or "skeleton" contained within the cytoplasm and composed of three types of fibers: microfilaments, intermediate filaments, and microtubules.
Centriole a barrel shaped microtubule structure that is an important part of centrosomes. The walls are usually composed of nine triplets of microtubules (protein of the cytoskeleton). The position of the centriole determines the position of the nucleus and plays a crucial role in the spatial arrangement of cell organelles.
Spindle fiber The structure that separates the chromosomes into the daughter cells during cell division.
Cytoplasm a gelatinous, semi-transparent fluid that fills most cells, it includes all cytosol, organelles and inclusions.
Cytosol the internal fluid of the cell where a portion of cell metabolism occurs.
Inclusions chemical substances found suspended directly in the cytosol.
Chromosome organized structures of DNA and proteins that are found in cells.
  • Text - Alberts, Bruce, et al. (2002) The Molecular Biology of the Cell (4th edition). Garland Science
  • Text - Lodish, Harvey, et al. (2004) Molecular Cell Biology 5th Edition. W. H. Freeman

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