Micro 1: Bacterial Structure And Classification

Front 1

bacterial genome

Back 1

lacks introns

single, circular dna

not bound by histone proteins

Front 2

bacterial cell walls

Back 2

peptidoglycan

provides rigidity to cell

major target for antimicrobial therapy

Front 3

gram positive bacterial

Back 3

thick and heavily cross-linked cell wall

Front 4

gram negative bacterial

Back 4

thin and lightly cross-linked

additional outer membrane

Front 5

bacterial components that differ from animal counterparts

Back 5

ribosome

RNA polymerase

topoisomerases

Front 6

Differences between prokaryotes and eukaryotes

Front 7

pili (fimbrae)

Back 7

sex pillus: used to transmit genetic material from one bacterium to another durig cconjugation

attach bacteria to host cell surfaces; without firm attachment colonization is difficult

Front 8

flagella

Back 8

whip-like structures that allow motile baccteria to "swim"

Front 9

capsules

Back 9

external sructures composed of polysaccharide or polypeptide

protect encapsulated bacteria from phagocytosis

found in meningitis

Front 10

spores (endospores)

Back 10

dehydrated, dormant forms that allow potential pathogens to survive during harsh conditions

gram positive rods (bacillus anthrax)

Front 11

Gram positive cell wall

Back 11

teichoic acid or lipoteichoic acid (polymers of glycerol phosphate or ribitol phosphate)

Front 12

gram negative cell wall

Back 12

peptidoglycan only two layers thick

lightly cross-linked

lies between inner and outer cytoplasmic membranes

Front 13

periplasmic space

Back 13

space where gram negative peptidoglycan lies; between cytoplasmic membranes

Front 14

outer membrane function

Back 14

additional permeability barrier

negatively charged

evade phagocytosis

inhibit antibiotic uptake

avoid action of complement

Front 15

porins

Back 15

molecular sieves in outer membrane that allow substrates like sugar to be transported across membrane

Front 16

degradtive enzymes

Back 16

periplasm

some destroy antibiotics

Front 17

lipopolysaccharide (LPS)

Back 17

only in gram negative bacteria

found in outer leaflet of membrane

contains lipid A (endotoxin), core polysaccharide, o antigen,

Front 18

lipid a

Back 18

recognized by the innate immune system to elicit a cytokine storm which leads to sepsis or septic shock

Front 19

sepsis

Back 19

primary cause is actually gram positive bacteria; eliciting antigen not clearly understood

Front 20

Gram negative secretion

Type I

Back 20

ATP binding cassette type

proteins are directly secreted into the extracellular environment from the cytoplasm

antimicrobial drugs can be expelled in this way

Front 21

Gram negative secretion

Type II

Back 21

found in all gram negative bacteria

general secretory pathway

proteins first secreted into periplasm before being secreted across outer membrane

Front 22

Gram negative secretion

Type III

Back 22

molecular syringes

structure allows direct injection of toxins and orther virulence factors into cytosol of a targeted cell

hydrophobic segments span cytoplasmic and outer membranes as well as plasma membrane

Front 23

Gram Stain

Back 23

suspension of bacterial cells is dried and heat-fixed to a glass slide

crystal violet is applied to cells

iodine fixes stain to cells

extensive cell wall of gram positive baccteria retains crystal violet

Front 24

counterstain

Back 24

safranin is used to dye gram-negative bacteria a red/pink color

Front 25

peptidoglycan

Back 25

repeating disaccharide of n-acetylmuramic acid (NAM) and n-acetylglucosamine (NAG)

Front 26

transglycosylase

Back 26

links disaccharides to form peptidoglycan

Front 27

pentapeptide cross-links

Back 27

pentapeptides come off of NAM residue of each disaccharide

cross-link to one another using transpeptidases and carboxypeptidases

Front 28

transpeptidases

Back 28

aka penicillin-binding proteins

targets of antibiotic penicilin

Front 29

cross linking difference between G+ and G-

Back 29

in G+, pentaglycine interpeptide links polypeptides

Front 30

terminal D alanine pair

Back 30

on NAM pentapeptides

critical to cross-linking process and ultimate d-alanine is removed by carboxypeptidase

target of antimicrobials

Front 31

cell wall assemby

Back 31

1. NAM-NAG disaccharides linked to a pentapeptide side chain synthesized

2. lipid carrier is used to transport disaccharide-pentapeptide subunits to external face of cyto membrane

3. subunit incorporated into the growing cell wall by action of glycosidases and transpeptidases

4. lipid carrier recycles to the interior leaflet of the cytoplasmic membrane to recharge with new cargo once dephosphorylated

Front 32

lysozyme

Back 32

natural defense that targets peptidoglycan cell wall

hydrolyzes bond between NAM and NAG

present in tears, saliva, lysosomes of phagocytic cells

particularly effective against gram positive bacteria

Front 33

types of B-lactams

Back 33

penicillin G

cephalosporins

carbapenems

monobactams

Front 34

Basic facts

Back 34

B-lactam ring resembles Dalanine terminal pair

bound by trans-peptidases

Front 35

B-lactamases

Back 35

cleave b-lactam rings

Front 36

vancomycin resistance

Back 36

occurs when D-alanine and D-lactone are synthesized instead of D-alanine and D-alanine

Front 37

B-Lactam mechanism

Back 37

require cell growth for activity

bacterial autolysins act much like lysozyme to cleave cell walls at sites for new subunit insertion

inhibit the cross-linking of new subunits, causing cell lysis

Front 38

mycoplasma

Back 38

lack cell wall

Front 39

chlamydia

Back 39

lack peptidoglycan

Front 40

mycobacterium

Back 40

waxy coat containing mycolic acid

use carbol fuschin to stain

acid-fast

Front 41

aerobic bacteria

Back 41

require oxygen and use respiration for growth

Front 42

anaerobic bacteria

Back 42

inhibited/killed in presence of oxygen and use fermentation exclusively for metabolism

Front 43

facultative anaerobabes

Back 43

majority of pathogens

use respiration in presence of oxygen and fermentation in absence

Front 44

microaerophilic bacteria

Back 44

can grow in absence of oxygen, but grow optimally at low oxygen concentrations

Front 45

fermentative bacteria

Back 45

produce variety of end productss from pyruvate

products used to classify bacteria

Front 46

antigenicity

Back 46

serotyping can identify the presence of specific antigens

used to distinguish strains within a genus

Front 47

genotyping

Back 47

most commonly, mapping of DNA fragment sizes is utilized

RFLP (restriction fragment length polymorphism) analysis can be used for rapid id