Prokaryotic Cell Structure

On Your Own Annotate the diagram of a bacteria cell with

the function of each structure.

Indicate whether the structure is found in all

or some prokaryotic cells.

Cell Membrane

• Controls passage of materials into and out

of the cell

• All cells have a cell membrane

Cytoplasm

• Fluid portion of all

cells

• Location of cellular

metabolism

Ribosomes

• Float freely in

the cytoplasm of

all cells

• The site of

protein

synthesis.

Nucleoid

• The glob of DNA in all prokaryotic cells

– Still a double helix

– Ends come together for form a circle

– Not wrapped around proteins as in eukaryotic cells (termed “naked DNA”).

Prokaryote vs. Eukaryote Chromosome

double helix

Prokaryote

Eukaryote

Plasmid • A small circle of DNA found

in some prokaryotes that

exists and replicates

independently of the main

DNA in the nucleoid.

• Often contain genetic

instructions for resistance to

antibiotics (antibiotics are

chemicals that kill bacteria)

Some Prokaryotes have a cell wall

• Gives shape, support

and protection to the

plasma membrane and

cytoplasm of the cell.

• Eubacteria wall made of

peptidoglycan* (protein-

sugar molecules).

• *different than plant cell walls, which

are made of cellulose

Flagellum

• Some bacteria have one or more

• Used for motility.

Pili

• Short fibers projecting from the cell wall

found on some bacteria.

• They may help the bacteria cling to

surfaces.

Capsule

• A special mucus-like protective coating

found on some disease-producing

bacteria.

Prokaryotic cells do not have

membrane bound organelles