•Cell Wall- present in plant, fungi, prokaryotes, and some protists; outer layer that
maintains cell's shape and protects cell from mechanical damage; made of cellulose, other
polysaccharides, and protein; one per cell
•Plasma Membrane- present in all cells; membrane enclosing the cell; one per cell
•Organelles bounded by a double lipid bilayer:
•Nucleus- present only in eukaryotic cells; surrounded by nuclear envelope perforated by
nuclear pores, the nuclear envelope is continuous with the endoplasmic reticulum; houses
chromosomes made of chromatin, contains nucleoli; pores regulate entry and exit of
material, about 5 um in diameter; directs protein synthesis by synthesizing mRNA
according to instructions provided by the DNA; one per cell
•Mitochondrion- present in eukaryotes; bounded by double membrane, inner membrane
has foldings (cristae); responsible for cellular respiration; many per cell
•Chloroplast- present in plants and algae; typically two membranes around fluid stroma,
which contains membranous thylakoids stacked into grana; responsible for photosynthesis;
many per cell
•Organelles bounded by a single lipid bilayer:
•The Endoplasmic Reticulum (ER): present in eukaryotic cells; network of membrane-
bound tubules and sacs, separates lumen from cytosol, continuous with the nuclear
envelope
•Rough ER- has ribosomes on the outer surface of the membrane and thus appears
rough; functions as making secretory proteins, membrane factory for cell
