Nucleolus

A specialized region in a cell nucleus where RNA is synthesized and assembled.

Chromatin

Humans and nearly all other species carry their genetic information in DNA. This DNA is packaged as chromatin. Chromatin fibers are coiled and condensed to form chromosomes.

Mitochondrion

Spherical or elongated structures found in most eukaryotic cells that produce most of the ATP in the cell.

Golgi apparatus

In eukaryotic cells, a series of flattened, hollow sacs surrounded by phospholipid bilayers and functioning to package large molecules for export in secretory vesicles.

Vacuole

General term for a membranous sac that stores or carries a substance in a cell.

Cell membrane

The cell membrane serves as a barrier and gatekeeper. It comprises a bilayer of phospholipids and encloses the semiliquid, gelatinous material called cytoplasm inside a cell.

Endoplasmic Reticulum

Netlike arrangement of hollow tubules continuous with the outer membrane of the nuclear envelope and function as a transport system.

Rough ER (RER)

Type of endoplasmic reticulum with ribosomes adhering to its outer surface; these produce proteins for transport throughout the cell.

Smooth ER (SER)

Type of endoplasmic reticulum that lacks ribosomes and plays a role in lipid synthesis and transport.]

Nucleus

Spherical to ovoid membranous organelle containing a eukaryotic cell’s primary genetic material.

Ribosome

A non-membranous organelle in prokaryotes and eukaryotes, composed of protein and ribosomal RNA and functions to make polypeptides.

Microbody

A cytoplasmic organelle bounded by a single membrane and containing oxidative enzymes. Microbodies include peroxisomes and glyoxysomes.