Leys

Question 1

A biofilm is a mixture of _____ and a matrix made up of ________

Answer 1

microbes

extracellular polymers.

Question 2

Bacteria form _____ within a biofilm.

Answer 2

complex structures

Question 3

Most biofilms are mixtures of ___

Answer 3

different species of bacteria.

Question 4

T o F: Biofilms can include microorganisms other than bacteria

Answer 4

True

Question 5

Biofilms have complex structures that give accessibility to _____ and removal of _____

Answer 5

nutrients

waste products.

Question 6

Bacteria in a biofilm are more or less resistant to antibiotics and host attacks?

Answer 6

More

Question 7

Where do most bacteria form biofilms?

Answer 7

in an environment where there is liquid flowing.

Question 8

Wild bacteria have extracellular______ that allow them to bind to surfaces or other bacteria.

Answer 8

polymers attached to their surface

Question 9

Wild bacteria have extracellular polymers attached to their surface that allow them to ____

Answer 9

bind to surfaces or other bacteria.

Question 10

Biofilms are associated with many diseases including ___

Answer 10

periodontal disease and caries.

Question 11

Many bacterial diseases (including oral infections) are ___

Answer 11

polymicrobial where several species are involved.

Question 12

_________ is the communication between bacteria.

Answer 12

Quorum sensing

Question 13

What are the two general mechanisms for quorum sensing?

Answer 13

One that recognizes similar bacteria (same species) and one that recognizes all bacteria.

Question 14

Do most bacteria have mechanisms for quorum sensing?

Answer 14

Essentially all bacteria have mechanisms for quorum sensing.

Question 15

When do the quorum sensing mechanisms produce a response?

Answer 15

when a certain threshold concentration of secreted molecules in reached.

Question 16

Quorum sensing is an essential process ____

Answer 16

in biofilm formation.

Question 17

Strict vs obligate vs facultative anaerobes

Answer 17

Strict aerobes must have oxygen to grow. Obligate anaerobes cannot tolerate oxygen and facultative anaerobes can grow with or without oxygen.

Question 18

DNA that enters a bacterial cell can be treated three ways:

Answer 18

1) degraded
2) integrated into the host chromosome
3) integrated into a plasmid (extrachromosomal element).

Question 19

How do bacteria degrade foreign DNA?

Answer 19

Restriction endonucleases or restriction enzymes

Question 20

What is transformation?

Answer 20

uptake of naked DNA by “competent cells.”

Question 21

What is transduction?

Answer 21

the transfer of DNA between bacteria through a virus.

Question 22

What is conjugation?

Answer 22

transfer of DNA through cell to cell contact using a sex pilus.

Question 23

Mutations in DNA can cause _____

Answer 23

antibiotic resistance

Question 24

Mutations can be the result of _____. Which are the least likely to cause antibiotic resistance?

Answer 24

base changes, deletions, insertions, duplications or rearrangements.
Deletions are the least likely to cause resistance

Question 25

Bacteria remove oxygen radicals from the cell by converting them to ______ with _______.

Answer 25

Hydrogen peroxide with superoxide dismutase.

Question 26

Catalase converts ______ to ______

Answer 26

hydrogen peroxide | water and oxygen

Question 27

Bacteria that do not have ________ will not tolerate oxygen; they are anaerobic.

Answer 27

superoxide dismutase and catalase

Question 28

Bacteroides are the most numerous members of

Answer 28

the normal flora of the human colon.

Question 29

Spillage of intestinal material into the ____ typically results in a biphasic disease: _______

Answer 29

peritoneal cavity | acute inflammation followed by localized abcesses.

Question 30

There are a _____ number of bacterial species present during the acute phase and a ____ number of species that predominate in abcesses.

Answer 30

large | small

Question 31

______ is the most common isolate from intra-abdominal abscesses.

Answer 31

Bacteriodes fragilis

Question 32

Bacteriodes fragilis is the most common isolate from ______

Answer 32

intra-abdominal abscesses.

Question 33

What is unique about the LPS on the surface of B. fragilis?

Answer 33

It is not toxic. This is unlike other gram neg bacteria

Question 34

Of the hundreds of species that are introduced into the peritoneal cavity by spillage from the colon, those (including B. fragilis) that have a _____ survive phagocytosis by the host.

Answer 34

polysaccharide capsule

Question 35

Intra-abdonimal abcesses cause by B. fragilis or other bacteria can lead to

Answer 35

bacteremia and septic shock.

Question 36

What is bacteremia?

Answer 36

the presence of bacteria in the blood, with or without the presence of an illness.

Question 37

What is sepsis?

Answer 37

a severe systemic illness marked by hemodynamic derangement and organ malfunction.

Question 38

Why is treatment of sepsis with antibiotics difficult?

Answer 38

because the dead bacteria can release toxins that initially cause more damage.

Question 39

Spirochetes are widespread in nature, many or few cause disease?

Answer 39

Few

Question 40

The corkscrew-like movement of spirochetes is facilitated by _____

Answer 40

periplasmic flagella.

Question 41

What is the causative agent of syphilis?

Answer 41

Treponema pallidum

Question 42

Why is treponema pallidum difficult to study?

Answer 42

Cannot be grown in lab

Question 43

When T. pallidum enters the body it becomes systemic almost immediately by

Answer 43

traveling through the lymphatic channels to the systemic circulation.

Question 44

How does the primary chancre formed by T. pallidum differ from the entire infection?

Answer 44

primary chancre heals spontaneously | Entire infection is systemic

Question 45

What happens to 50% of patients that do not receive treatment for syphilis?

Answer 45

They enter the secondary stage of the disease

Question 46

______ produced by secondary syphilis is often mistaken for other problems.

Answer 46

The rash

Question 47

Tertiary syphilis, if left untreated, can progress to the CNS, causing _____

Answer 47

ataxic gait, paresis, blindness, dementia and death.

Question 48

____ is one of the easiest STDs to control. There are good diagnostic tests and treatment is available and inexpensive.

Answer 48

Syphilis

Question 49

Borrelia burgdorferi is the causative agent of

Answer 49

Lyme’s disease.

Question 50

What causes Lyme's disease?

Answer 50

Borrelia burgdorferi

Question 51

Like syphilis, Lyme’s disease progresses in stages from an _____ to a ______

Answer 51

acute and local skin infection | chronic disease of the CNS and joints.

Question 52

B. burgdorferi is transmitted by

Answer 52

ticks.

Question 53

Which microbe is transmitted by ticks?

Answer 53

B. burgdorferi

Question 54

There are _______ bacterial species found in the oral cavity, from a wide variety of phyla.

Answer 54

500 – 1000

Question 55

Different bacteria occupy different environmental niches. Subgingival bacteria are generally ______. Supragingival bacteria are generally________.

Answer 55

proteolytic | sacchrolytic

Question 56

Factors that promote colonization in the oral cavity include _______

Answer 56

``` adherence properties synergistic bacteria nutritional substrates temperature moisture content. ```

Question 57

Factors that inhibit colonization in the oral cavity include

Answer 57

antimicrobial properties of saliva mechanical shearing antagonistic bacteria.

Question 58

There are many bacterial species that are associated with periodontitis, while fewer species are associated with

Answer 58

periodontal health.

Question 59

Shifts in microbial composition occur in _____, however no bacterium is found in all patients with periodontitis and never found in healthy subjects.

Answer 59

periodontitis

Question 60

The tissue destruction that occurs during periodontitis is mainly the result of

Answer 60

a host response.

Question 61

There is a small shift from ____ to ______ during periodontitis.

Answer 61

gram positive | gram negative

Question 62

The complexity of the ______ increases during periodontal disease.

Answer 62

microbial community

Question 63

There is a slight shift to ______ in periodontitis.

Answer 63

more uncultivated bacteria

Question 64

Microbial diversity ____ in caries.

Answer 64

declines

Question 65

There is a progression of ____ as caries progresses.

Answer 65

dominant species

Question 66

Each location in the ____ has its own associated microbial composition. However there is overlap of species.

Answer 66

oral cavity