L4

Question 1

Plaque biofilm

Answer 1

Cooperating community of organisms with interbacterial and host-bacterial interactions

Question 2

Stages of biofilm

Answer 2

Free swimming
Attachment
Growth
Maturation
Succession

Question 3

Pellicle is made up of

Answer 3

Salivary glycoproteins

Antibodies

Question 4

Bacteria after attachment

Answer 4

Synthesis of new outer membrane proteins

Active cellular growth

Question 5

Co-Aggregation

Mediated by

Answer 5

Cell-Cell recognition of genetically distinct type in solution
Mediated by Protein/glycoprotein on one cell and carb on another

Question 6

Co-adhesion

Answer 6

Cell-Cell Recognition of genetically distinct types when one is already adhering to surface

Question 7

Influences on Co-adhesion

Answer 7

Temperature (none above 37 degrees)

Lactose (increase Lac decreases co-adhesion

Question 8

Maturation involves

Answer 8

Replication
Metabolic partners
Firm attachment
Extracellular matrix

Question 9

Primary colonizers

Answer 9

Mostly Gram (+)
Streptococci

Question 10

Secondary colonizers

Answer 10

Fusobacterium Nucleatum

Question 11

Tertiary colonizers

Answer 11

Porphyromonas Gingivalis

Question 12

Sources of matrix

Answer 12

Dead bacterial cells
Saliva
Gingival exudate

Question 13

Gram POSITIVE matrix is very _____

Contains (2)

Answer 13

Fibrillar due to dextrans and levans

Question 14

Bacteria near sulcular epithelium vs tooth attached

Answer 14

No interbacterial matrix

More spirochetes and flagellated bacteria

Question 15

Robust biofilm in the presence of O2

Answer 15

Strep cristatus: factultative aerobe
Fusobacterium nucleatum: Anaerobe wants strep
Porphyromonas gingivalis: ob. anaerobe NEEDS coaggregation

Question 16

Advantages of biofilm living

Answer 16

Defense
Protection from external changes
Transfer of information and genetic material

Question 17

S. Cristatus can enter epithelial cells by

Answer 17

F. Nuc brings it in and this is dangerous because S.cristatus is gram (+)

Question 18

Mechanisms for resistance

Answer 18

Biofilm bacteria grow more slowly
Exo-polymers retard diffusion (Ion exchange and enzymes that inactivate antibiotics)
Expression of different genes

Question 19

Backbone of biofilm

Answer 19

Exopolysaccharides

Question 20

Lower layer descrition

Answer 20

Tightly bound
Steep diffusion gradient
Polysaccharide matrix

Question 21

Layers of biofilm

Answer 21

Lower Layer
Loose Layer
Fluid layer: nourishes biofilm by molecular diffusion