Prokaryotic Cells

a. Lack a membrane bound nucleus and are structurally smaller and simpler than ________ _______, which do have a true nucleus.

b. Prokaryotic cells are placed into two taxonomic domains:

1. Bacteria/Eubacteria: Cause diseases but are also environmentally important as decomposers; can be useful in manufacturing products and drugs

2. Archaea: live in extreme habitats

c. Prokaryotes are extremely small, 1-1.5µm and 2-6µm long, usually occur in three shapes:

1. spherical (coccus, cocci)

2. ii. rod-shaped (bacillus, bacilli)

3. spiral (flexible spirillum or rigid spirochete)

d. Cell envelope contains:

1. plasma membrane (lipid bilayer with embedded and peripheral proteins that can mesosomes (internal pouches that increase surface area)

2. cell wall to maintain the shape of the cell and is strengthened by peptisoglycan

3. glycocalyx, a layer of polysaccharides exterior to the cell wall on SOME bacteria

e. ________________ – a semifluid solution encased by the plasma membrane; contains water, inorganic and organic molecules, and enzymes

f. ________________ – region that contain a single, circular DNA model

g. ______________ — small extrachromsomal rings of DNA

h. ______________ — tiny structures in the cytoplasm where proteins

are made

i. External structures

1. flagella (for motility)

2. fimbriae (for attachment)

3. conjugation _________ (for passing DNA from cell to cell)