Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BDS2 Oral Biology > Dental Plaque and Biofilms (4) > Flashcards

Dental Plaque and Biofilms (4) Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

Do biofilms create their own environment?

A

yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are 2 types of biochemical interactions n a biofilm?

A

synergistic
antagonistic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are examples of synergistic biochemical interactions of bacteria in a biofilm?

A

enzyme complementation

food chains

coaggregation/coadhesion

cell-cell signalling

gene transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are examples of antagonistic biochemical interactions of bacteria in a biofilm?

A

bacteriocins

hydrogen peroxide

organic acids

low pH

nutrient competition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is enzyme complementation?

A

Some oral bacteria possess different but overlapping patterns of enzyme activity

division of labour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does this diagram represent?

A

enzyme complementation

bacteria may rely on other bacteria in the biofilm to get in there first and cut off an end sugar from an oligosaccharide side chain to expose a new sugar and allow it to metabolise

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Does enzyme enzyme complementation allow?

A

Avoid competition for nutrients and can therefore co-exist

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where does supragingival plaque gain most of its nutrients from?

A

saliva - not diet unless sucrose intake is high

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What bacteria does sucrose favour?

A

streptococci

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does streptococci metabolising sucrose form?

A

both intra and extracellular
polysaccharides for use as a nutrient supply when sucrose is not available

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What do streptococci use as a nutrient supply when sucrose is not available?

A

both intra and extracellular polysaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the early colonisers e.g. S. sanguins equipped to do?

A

equipped to break down salivary glycoprotein

a reliable source of nutrient in the pellicle and plaque matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where does the GCF come from?

A

rich and constant source

from the connective tissue under gums, through the junctional epithelium and into the gingival crevis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What do some bacteria in the subgingival plaque require?

A

growth factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a primary feeder?

A

feeds first

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a secondary feeder?

A

the products of metabolism of one microorganism (Primary Feeder) become the main source of nutrients for another organism (Secondary Feeder)

the growth of some species being dependant on the metabolism of other organisms

17
Q

Describe a simple food chain between S. mutans and Veillonella

A
18
Q

How do secondary colonisers attach to primary colonisers?

A

by intra- and inter-genetic Coadhesion/Coaggregation (lectin mediated)

This can also facilitate metabolic interactions
between mutually-dependant strains

19
Q

Can genes for fructan andglucan synthesis be differenentially regulated?

A

yes

Genes involved with glucan (gtfBC) and fructan (ftf) synthesis in S mutans are
differentially regulated during biofilm formation:

Early plaque formation – no change

Late plaque formation (7 days) - gtf expression is markedly upregulated and ftf supressed

20
Q

What molecules are involved in quorum sensing?

A

These include Acyl-homoserine Lactones (AHL) produced by G-ve bacteria and small peptides secreted by G+ve bacteria

21
Q

What is quorum sensing?

A

cell density dependent growth

22
Q

What type of gene transfer occurs in biofilms?

A

horizontal gene transfer

23
Q

What types of sensing can induce gene transfer?

A

Signalling molecules such as those involved in QS can markedly increase the ability of recipient cells to take up DNA

24
Q

What is an example of successful gene transfer?

A

Resident S mitis and S oralis and pathogenic S pneumoniae bacteria isolated from the naso-pharyngeal area possess genes conferring penicillin resistance that display a common mosaic structure

common goods

25
Q

What is an example of an antagonistic interaction?

A

Bacteriocins or bacteriocin-like substances (BLIS) are high molecular weight proteins which can inhibit the growth of related bacteria while the producer strains are resistant to the actions of the bacteriocins they produce

26
Q

Do both gram - and + bacteria have anatagonsistic interacting species?

A

Produced by most species of oral streptococci and are broad-spectrum, inhibiting species belonging to the G+ve and G-ve genera

27
Q

What advantage will bacteriocins give bacteria?

A

The production may give strains a competitive advantage during colonisation

28
Q

Other than bacteriocins, what other inhibitory factors can bacteria produce?

A

Hydrogen Peroxide
Organic Acids
Enzymes

29
Q

What can antagonisms result in?

A

Antagonism can also result in the prevention of exogenous bacteria from colonising the oral cavity

30
Q

Do the antagonistic factors always lead to exclusion of species?

A

no, but can prevent exogenous bacteria from colonising oral cavity

31
Q

What is the ability to maintain stability in a variable environment called?

A

microbial homeostasis

32
Q

Bacteria can maintain homeostasis, but what are some challenges presented form the body?

A
  • host defences
  • environmental stresses
33
Q

What are examples of environmental stresses that the body poses?

A

Saliva composition and flow
GCF composition and flow
Diet
Challenge by exogenous species
Hormone levels
Antimicrobials in toothpaste and mouthwashes
Physical disturbance

34
Q

What is the essential mechanism of microbial homeostasis?

A

When the environment is disturbed, self-regulatory mechanisms (homeostatic reactions) come into force to restore the balance

An essential component of this mechanism is negative feedback, whereby a change in one or more organisms results in a response by others to neutralise or oppose the change

35
Q

When is microbial homeostasis greatest?

A

in communities that shown the greatest diversity

36
Q

When can microbial homeostasis breakdown?

A

immunological disorders

non-immunological factors

37
Q

What are examples of immunological disorders which breakdown microbial homeostasis?

A

slgA-deficiency
Neutrophil dysfunction
immunosuppression

38
Q

What are examples of non-immunological factors which breakdown microbial homeostasis?

A

Xerostomia
increased GCF flow
diet - high in refined carbohydrates
hormones

BDS2 Oral Biology (27 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions