Bacterial Classification and Structure

Question 1

which bugs have capsule as major virulence factor?

Answer 1

SOME KILLERS HAVE PRETTY NICE CAPSULES

1. strep pneumoniae
2. kliebsiella pneumoniae
3. haemophilus influenzae
4. pseudomonas aeruginosa
5. neisseria meningitidis
6. cryptococcus neoformans

Question 2

where are pili found

Answer 2

gram negative only

Question 3

what component is responsible for cell shape and structural rigidity

Answer 3

peptidoglycan

Question 4

what makes up peptidoglycan

Answer 4

NAG and NAM that are crosslinked by tetrapeptide bridge

Question 5

describe gram positive cell wall

Answer 5

thick peptidoglycan, highly crosslinked, has lipoteichoic acid and teichoic acids

Question 6

what do lipoteichoic acids do

Answer 6

anchor cell wall to cell membrane and mediate attachment

Question 7

what do teichoic acids do

Answer 7

taxonomic markers , antigenic determinant

Question 8

gram negative cell structure

Answer 8

2 membranes inner and outer, with periplasmic space, has less peptidoglycan with less crosslinkage

Question 9

describe outer membrane of gram negative cell

Answer 9

gram negative has LPS, there is no active transport or enzymatic activity, there are porins and receptor proteins

Question 10

what is a main part of LPS?

Answer 10

Lipid A

Question 11

what is Lipid A?

Answer 11

heat stable endotoxin with a core region and polysaccharide side chain (o antigen) – a pyrogen

Question 12

what does Lipid A do?

Answer 12

activates macrophages and complement and B cells
induces IFN production
causes tissue necrosis
pyrogen

Question 13

what does O antigen do

Answer 13

is a major serologic determinant and a virulence factor (if smooth making O antigen, if rough not making O antigen)

Question 14

what is in the periplasmic space?

Answer 14

1. binding proteins
2. degradative enzymes
3. detoxifying enzymes
4. super thin peptidoglycan cell wall

Question 15

what detoxifying enzymes are in the periplasmic space?

Answer 15

beta lactamases (inhibit penicillin and cephalosporins, carbapenems, monobactams)

Question 16

describe the inner membrane of (both gram positive and negative)

Answer 16

similar in both, NO STEROLS, osmotically fragile

HAS ENZYMATIC ACTIVITY, acts like osmotic barrier

Question 17

what type of activity does the cytoplasmic/inner membrane have?

Answer 17

1. electron transport
2. ox phosphorylation
3. synthesis of peptidoglycan
4. active transport
5. bounds ribosomes
6. simple and facilitated diffusion

Question 18

where do endospores come from

Answer 18

gram positive

Question 19

what is the purpose of becoming a spore

Answer 19

to survive and be stable not reproduce

Question 20

what triggers spore formation?

Answer 20

exhaustion of carbon or nitrogen source

Question 21

what is a big clue that someone has spore infection?

Answer 21

accumulation of large amounts of calcium and dipicolinic acid

Question 22

structure of endospore

Answer 22

1. core with genome, DNA and ribosomes
2. spore wall with peptidoglycan
3. cortex with new peptidoglycan
4. coat
5. exosporium loose covering

Question 23

is there RNA or free AA in endospore core>

Answer 23

no

Question 24

thickest layer in endospore

Answer 24

cortex - concentric layers give strength

Question 25

what is the benefit of a spore coat?

Answer 25

disulfide bonds and keratin like protein makes it resistant to chemicals and radiation

Question 26

what triggers activation of spore germination?

Answer 26

either spontaneous or heat, aging, low pH, or chemical treatments

Question 27

what occurs when spore germinates?

Answer 27

produces Ca and dipicolinic acid, hydrolysis begins and brings in water, but loses heat resistance

Question 28

what is crucial for spore germination?

Answer 28

water

Question 29

which bacteria are spore formers

Answer 29

1. clostridium tetani
2. clostridium botulinum
3. bacillus anthracis
4. bacillus cereus