August 22 Flashcards
what are the 3 major divisions of the living world
bacteria (eubacteria), eukaryotes, and archaea (archaebacteria)
function of plasma membrane
selective barrier that allows cells to maintain integrity
function of nucleus
store house of information
function of ER (general)
lipid and protein synthesis and intracellular calcium store
function of rough ER
ribosomes synthesize proteins
function of smooth ER
calcium storage, (called sarcoplasmic reticulum)
transport vesicles bud off and transport newly synthesized proteins and lipids to golgi (called transitional ER)
function of golgi
major site of carbohydrate synthesis, sorting, and dispatching of products made in the ER
function of mitochondria
energy metabolism, oxidative phosphorylation and krebs cycle, also has distinct mitochondrial DNA separate from DNA in nucleus
function of lysosomes
intracellular digestion of macromolecules
what performs the degradation of macromolecules in lysosomes
hydrolytic enzymes
function of fimbriae (or pili)
attachment to surfaces for bacterial cells
function of flagella
motility for bacterial cells
function of lipopolysaccharides
activate inflammatory responses in bacterial cells
function of capsules
may play a role in dental caries in bacterial cells
describe a gram positive bacterial cell wall
- thick peptidoglycan layer
- teichoic acid
- one membrane
what color are gram positive bacterial cells
purple-blue
what color are gram negative bacterial cells
pink-red
describe a gram negative bacterial cell wall
- 2 membranes- outer and inner
- lipopolysaccharide outer membrane
what is a peptidoglycan made of
alternating NAM and NAG sugars
what are the chains crosslinked by in a peptidoglycan
oligopeptides
what does NAM stand for (the sugar in peptidoglycans)
acetylmuramic acid
what does NAG sugar stand for in a peptidoglycan
N- acetylglucosamine
what enzyme is responsible for the crosslinking in peptidoglycans
transpeptidase
what inhibits transpeptidase
ampicillin
how thick is the phospholipid bilayer
5nm
what are biofilms
a cooperating community of microorganisms within a matrix that is attached to a surface
where do biofilms develop
in any fluid environment containing microorganisms that are subjected to stress or fluid flow
where do dental biofilms exist
on tooth surfaces and mucosal surfaces of the oral cavity
where do bacteria attach
a pellicle
what does a pellicle form from
proteins in the saliva or GCF
what are the four stages of dental plaque biofilm growth
attachment (lag), growth (log), maturity (stationary), dispersal (death)
what type of bacterial cells exist in the lag phase
gram positive cocci and rods
what occurs in the log phase
cross linking via fusobacterium species
what type of bacterial cells exist in the stationary phase
gram negative
how do bacterial within bacterial microcolonies communicate
via chemical signals
explain the structural complexity of a dental biofilm
in order : tooth, pellicle, fluid channels, bacterial microcolinies and intermicrobial matrix
what happens in bacterial microcolonies in a dental biofilm
they adjust their pH, have varying nutrient supplies, and can induce gene expression
what do fluid channels do in a biofilm
movement of nutrients, waste products, metabolites, enzymes, and oxygen
what do cariogenic bacteria use to produce extracellular polysaccharides
sucrose
what happens with sucrose in dental biofilms
its soluble so it diffuses rapidly into plaque biofilm where it becomes a substrate for extracellular polysaccharides
what does sucrose get split into
glucose and fructose
what does glucose get used for in biofilms
it can be built into homopolymers of glucose called glucans such as mutan (water insoluble) and dextran (water soluble)
how do extracellular polysaccharides “help” bacteria grow
they serve as a nutritional source for bacteria which supports further adhesion and accumulation of plaque
what are the main causal agents for caries (bacteria)
streptococcus mutans and lactobacillus casei and lactobacillus fermentum
where do saccharolytic bacteria derive energy drom
glycolysis
how do saccharolytic bacteria use glycolysis
they convert glucose into pyruvate then pyruvate into lactic acid
what do biofilms form on tooth surfaces
dental plaque
what is calculus or tartar
plaque that has been calcified
where do dental caries form
pits and cavities of teeth
in patients with healthy dentition and no periodontal disease, what is the most common bacteria in the dental biofilms
gram positive
what do gram positive bacteria do to elicit a cavity
ferment sugars to a final end product of lactic acid
what does the production of lactic acid result in
a low pH, which can result in demineralization of the tooth enamel and dentin resulting in a carie
what do asaccharolytic bacteria derive energy from
amino acids
how do asaccharolytic bacteria derive their energy
by reducing or deaminating free amino acids
what compounds from amino acid reduction and amino acid deamination cause dental plaque
ammonium acetate, ammonium propionate, and ammonium butyrate
what does dental calclulus promote
asaccharolytic fermentaion
what happens in assacharolytic fermentation
cysteine and methoionine are fermented to produce hydrogen sulfide which causes oral malodor
what does saliva contain
99% water, Na, K, Ca,Mg, bicarbonate and phosphates, immunoglobulin proteins, enzymes, mucins and nitrogenous products such as urea and NH3
what are the types of saliva
serous, mucos, and mixed serous and mucos
what creates serous saliva
parotid glands
what produces mucos saliva
minor glands
what produces mixed serous and mucos saliva
sublingual and submandibular glands
what are the functions of saliva
- lubrication and protection
- buffering
- maintains tooth integrity
- antibacterial activity
- taste and digestion
how much saliva is produced per day
750-1000 mL
how much GCF is secreted per day
1-2 mL
where is GCF secreted
into the space (gingival sulcus) between the surface of the tooth and the free mergin of the epithelium lining of the gingivia
what are the functions of the GCF
- cleansing the sulcus
- improve adhesion of the epithelium to the tooth
- antimicrobial properties
- antibody defense of the gingiva
what does the protein rich environment of GCF provide
fermentation of amino acids causes a high pH that prevents caries from developing but can lead to precipitation of calcium and phosphate on a dental biofilm (plaque) and eventually calculus
