Prokaryotic Cells Structure and Function Prokaryotic Cell Structure

Prokaryotic Cells Structure and Function

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.

Plasma (Cell) Membrane • Controls passage of materials into and out of the cell • All cells have a plasma 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. Are 70 S in prokaryotes, slightly smaller than the 80 S ribosomes found in Eukaryotes. (S) stands for Svedberg units.

Nucleoid • The glob of DNA in all prokaryotic cells – Still a double helix – Ends come together form a circle – Not wrapped around proteins as in eukaryotic cells (termed “naked DNA”).

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* (proteinsugar 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