Prokaryotic Cell Structure

Question 1

cytoplasm

Answer 1

all cellular contents (organelles and cytosol) between the nuclear and plasma membranes

Question 2

cytosol

Answer 2

the semi-fluid portion of the cytoplasm

Question 3

nucleoid

Answer 3

region of the prokaryotic cytosol where the large, circular chromosome is condensed

Question 4

external organization of prokaryotes

Answer 4

almost always a cell wall, may also include a combination of flagella, fimbriae, pili or capsules

Question 5

fimbriae

Answer 5

short, numerous, hair-like protein structures observed on outside of bacteria (not archaea)
-used for adhesion (forming biofilms and colonizing hosts)

Question 6

basal apparatus

Answer 6

motor of the prokaryotic flagellum, anchored in the plasma membrane and cell wall

Question 7

gram positive

Answer 7

bacterial cell walls that contain a thick layer of peptidoglycan on top of a plasma membrane
(no antibiotic resistance)

Question 8

gram negative

Answer 8

bacterial cell wall with a thin layer of peptidoglycan topped by an outer bilayer

• prevents entry of many chemicals, including antibiotics
• protects against immune defenses
• lipopolysaccharides on exterior stimulate fever and toxic shock

Question 9

flagella

Answer 9

external structures used for cell movement
(although motor is anchored in cell membrane and wall)
-powered by proton gradient (H+ pumped out of the cell diffuses back in through basal apparatus, causing the hook to rotate the long filament)
-composed of flagellin

Question 10

gram positive

Answer 10

bacterial cell walls that contain a thick layer of peptidoglycan on top of a plasma membrane

Question 11

biofilm

Answer 11

layers of bacteria embedded in common capsular membrane

-tends to form in wet environments (plaque on teeth)

Question 12

penicillin

Answer 12

antibiotic that targets bacterial cell walls

• inhibits the enzyme that cross-links peptidoglycan in cell wall synthesis
• some bacterial plasmids are encoded with amp^R gene for a secreted enzyme that breaks down penicillin
• archaeal cells don’t have peptidoglycan so they won’t be affected!

Question 13

kanamycin and tetracycline

Answer 13

antibiotics that target bacterial ribosomes, preventing protein production

• kan^R gene encodes enzyme that modifies kanamycin, preventing it from binding to the bacterial cell wall
• archaeal ribosomes have different sequences so they won’t be affected!