SOS

Question 1

Majority of the microbes that cause oral disease are ___

Answer 1

bacteria and bacterial structure

Question 2

inflammation of the gums is called

Answer 2

gingivitis

Question 3

Oral microbiome is composed of __1.__, whereas mycobiome is composed of _2.___

Answer 3

1. bacterium

2. fungi

Question 4

T/F: bacteria have a true nucleus

Answer 4

False. Bacteria have a NUCLEOID (nuclear membrane absent). Also no membrane bound organelles

Question 5

Bacterial cell multiplication occurs by ___ ___

Answer 5

bianry fission (dividing in two). 1—2—4—8—16—. Each daughter cell has the same DNA as parent cell

Question 6

4 general composonents of bacterial structure

Answer 6

a. surface structures (ex flagella, fimbriae, pili, capsule/slime layer)
b. cell wall
c. cytoplasmic membrane
d. cytoplasm

Question 7

What structure allows motility in bacteria?

Answer 7

flagella

Question 8

flagella are composed of multiple subunits of the protein ____

Answer 8

flagellin

Question 9

Function of fimbriae

Answer 9

• fimbriae are shorter and straighter than flagella
• found all over bacterial cell
• aid in BACTERIAL ATTACHMENT to surfaces or to other bacteria

Question 10

what surface structure serve to promote gene transfer between bacteria and attachment?

Answer 10

pili

Question 11

Which is more numerous in bacteria? Pili or fimbrae?

Answer 11

Pili < fimbrae

Question 12

a slime layer is (more/less) diffuse than a capsule

Answer 12

more

Question 13

Capsule / slime-layer serve to promote:

Answer 13

a) adhesion to tissue surfaces
b) evasion of phagocytosis by immune cells
c) provides resistance to environmental stress (eg. drying)
d) acts as disguise from an immune response
e) supply of emergency food resevoir

Question 14

Which strain of bacteria was isolated from an adult patient with periodontitis?

Answer 14

P. gingivalis

Question 15

Which strain of bacteria was isolated form a patient with cystic fibrosis?

Answer 15

P. aeruginosa

Question 16

What acids present in the cell wall of the mycolata taxon and what effect does this have?

Answer 16

Mycolic acids. These prevent gram staining

Question 17

roughly 50% of periodontitis patients harbour ____

Answer 17

methanogens

Question 18

The amount of methanogens increases with increasing ____ ___

Answer 18

pocket depth

Question 19

Methanogen abundance is positively correclated with ____ ____ (an obligatiev anaerobe)

Answer 19

prevotella intermedia

Question 20

Peptidoglycan function

Answer 20

• mech protection
• activates alternative complement pathways (induces inflammation via C3a and C5a)
• Gram + cells are more resistant to detergents and complement

Question 21

What is found on the outer membrane of Gram -ve bacteria?

Answer 21

Lipopolysaccharides. Used as an ADHESIVE. Highly toxic to animals

Question 22

Lipopolysaccharides consist of:

Answer 22

• lipid A region (toxic)
• R polysaccharide core region
• carbohydrate chains (O region, antigenic)

Question 23

Lypopolysaccharide activates…

Answer 23

alternative complement pathway (LPS induces inflammation)

Question 24

Lipopolysaccharides act as barriers to what?

Answer 24

large and hydrophobic molecules.

Lysosomes and antimicrobials

Question 25

Purified LPS causes

Answer 25

fever, intravasculat coagulation, hypotension, shock and may even cause death

Question 26

Lipid A is highly conserved among gram ____ bacteria

Answer 26

negative | in the cell wall

Question 27

What does lipid A do

Answer 27

-induces monocytes and macrophages to release proinflammatory mediators (eg. cytokines, which are molecules that help the cell move) -Activated coagulation cascade LIPID A IS A POTENT STIMULATOR OF THE IMMUNE RESPONSE

Question 28

Which acids are present in gram +ve cell walls?

Answer 28

teichoic acids. - strong neg charge - strong antigens - used as an adhesin - not present in most gram -ve bacteria

Question 29

T/F: cytoplasmic membrane is a phospholipid bilayer in gram -ve and +ve bacteria

Answer 29

true

Question 30

Functions of the cytoplasmic membrane:

Answer 30

- selective barrier - transport in and out of cell - secretion - NRG generation (ATP synthesis)

Question 31

gene transfer in bacteria

Answer 31

1. conjugation 2. transduction 3. transformation 4. transposition

Question 32

What causes antibiotic resistance?

Answer 32

"jumping genes." One gene integrates into another, causing destruction of the sequence in the other gene (transposition)

Question 33

based on type of action, antibiotics are either __ or __-

Answer 33

bacteriostatic or bactiocidal

Question 34

antibiotic synergism

Answer 34

when 2 bactericidal antibiotics are given together and exert a greater effect than when given seperately

Question 35

antibiotic antagonism

Answer 35

when a bacteriostatic and a bactericidal antibiotic are given together and their effectiveness is reduced

Question 36

penicillin is only effective against gram ___ bacteria

Answer 36

positive

Question 37

Common cellular target of antibiotics

Answer 37

- cell wall (eg. penicillin) - cell membrane - nucleic acids - protein synthesis - antimetabolites (enzymes)

Question 38

Which taste receptors are activated by multiple antibiotics?

Answer 38

chemosensory BITTER taste receptors (T2Rs)

Question 39

From where should sample be taken when examining ECC (early childhood caries?

Answer 39

from plaque bacteria, since this is different from bacteria in the buccal cavity and spit

Question 40

plaque bacteria associated with caries

Answer 40

- streptococcus mutans (+) = cocci - streptococcus sanguis (+) = cocci - actinomyces spp (+) = branching rods - lactobacillus (+) = rods

Question 41

Angular chailitis

Answer 41

- often confused with cold sores | - caused by staphylococcus aureus

Question 42

The oral micloflora are mostly __1.__, but changes in physiological conditions results in some of the oral microflora turning into 2.____ ____

Answer 42

1. commensals | 2. opportunistic pathogens

Question 43

Major oral habitats

Answer 43

1. buccal mucosa (inside the cheek) 2. dorsum of tongue (highest concentration) 3. tooth surfaces 4. cervicular epithelium

Question 44

Physiological roles of gingival epithelium

Answer 44

- protects against invasion by periodontal pathogen | - barrier