1.2.1 PLTW MI Quiz

what is a prokaryote

a cell without a nucleus or membrane-bound organelles

cytoplasm

gel like fluid filling the cell

ribosomes

makes proteins

nucleoid

region containing the bacterial chromosome

plasmids

small circular DNA carrying extra genes

pili

help bacteria attach and transfer DNA

capsule

protective outer coating; helps attachment and avoiding immune defenses

cell wall

provides shape, support, and protection

flagellum/flagella

tail like structures used for movement

plasma membrane

controls what enters and leaves the cell

peptidoglycan

strong material found in bacerial cell walls

what is an endotoxin

LPS associated with gram negative outer membranes

what is an exotoxin

a protein toxin produced and usually released by bacteria

gram positive: peptidoglycan layer?

thick

gram negative: peptidoglycan layer?

thin

gram positive: final stain color?

purple - retains crystal violet

gram negative: final stain color?

pink/red - takes up safranin

which gram type has an outer membrane

gram negative

which gram type contains LPS (endotoxin)

gram negative

why are gram negative bacteria often harder to treat

their extra outer membrane blocks some antibiotics

examples of gram positive bacteria

staphylococcus, streptococcus, clostridium

examples of gram negative bacteria

e. coli, salmonella, neisseria, pseudomonas

penicillins: examples?

penicillin, amoxicillin, ampicillin

penicillins: how do they work?

stop bacterial cell wall buildings, weakening the wall

tetracyclines: examples?

doxycycline, minocycline, tetracycline

tetracyclines: how do they work?

bind to ribosomes and stop protein production

fluoroquinolones: examples?

ciprofloxacin, levofloxacin, moxifloxacin

fluoroquinolones: how do they work

block enzymes needed to copy bacterial DNA

sulfonamides: examples?

sulfamethoxazole, sulfadiazine, sulfacetamide

sulfonamides: how do they work?

block folic acid production needed for bacterial growth

what is neisseria meningitidis

a gram negative diplococcus that can cause meningitis

what does diplococcus mean

two round bacterial cells paired together

what antibiotic can treat meningococcal infection

ceftriaxone, a cephalosporin that blocks cell wall building

why are penicillins often more effective on gram positive bacteria

their cell wall is accessible; gram negative bacteria have an outer membrane

why can antibiotics target bacteria without harming human cells as much

they target bacterial features that human cells lack or have differently

why don’t antibiotics kill viruses

viruses lack bacterial cell walls, ribosomes, and other antibiotic targets

what is the bacterial chromosome’s shape

usually circular, double stranded DNA

what is one benefit of plasmids

can carry antibiotic resistance genes

what is the capsule’s main protective function

helps bacteria avoid immune defenses

how do pili help bacteria spread resistance

they help transfer DNA between bacteria

what does semipermeable mean

allows some substances through, but not others

what is the plasma membrane made of

a phospholipid bilayer

what is the cell envelope

the layers surrounding a bacterial cell

what does LPS stand for

lipopolysaccharide

where is endotoxin located

gram negative outer membrane

when can endotoxin be released

when bacteria die or break apart

can some exotoxins be inactivated by heat

yes

can antibodies neutralize some exotoxins

yes

gram positive: outer membrane?

no

gram negative: outer membrane?

yes

gram positive: main cell wall material?

thick peptidoglycan

gram negative: where is peptidoglycan?

between the ineer and outer membranes

why do gram positive bacteria stain purple

thick peptidoglycan retains crystal violet

why do gram negative bacteria stain pink

lose crystal violet and take up safranin

which gram type is often more vulnerable to natural penicillin

susceptible gram positive bacteria

what is one infection caused by gram positive bacteria

strep throat or a staph infection

what is one infection caused by gram negative bacteria

UTI, pneumonia, or meningitis

penicillins: what structure do they target

the bacterial cell wall

penicillins: gram positive, gram negative, or both?

both, depending on the drug, natural penicillin mainly targets susceptible gram positive bacteria

tetracyclines: what structure do they target?

bacterial ribosomes

tetracyclines: gram positive, gram negative, or both?

both

fluoroquinolones: what do they target?

enzymes needed for DNA replication

fluoroquinolones: gram positive, gram negative, or both?

btoh - coverage varies by drug

sulfonamides: what process do they block

folic acid synthesis

sulfonamides: gram positive, gram negative, or both?

both - susceptibillity varies

what shape is neisseria meningitidis

diplococcus: two round cells together

what is bactrim

sulfamethoxazole + trimethoprim