Lecture 19 Flashcards
(30 cards)
What are risk factors of Dental Caries?
- Diet (Western diet)
- High sugar content
What does Acid do?
Causes loss of calcium & phosphate from tooth = demineralisation
Describe the Pathogenesis of Dental Caries
Action of acids on tooth
- Bacterial acids produced when sugars (mainly sucrose) from foods/drinks metabolized by bacteria in dental biofilm/plaque on tooth surface
What are early caries?
Small patch of demineralized/softened enamel in fissures or between teeth
Where does the destruction of dental caries spread to?
Softer dentine & weakened enamel collapses to form cavity
- Can attack roots if exposed by gum recession
What do Cariogenic bacteria produce?
Lactic, formic, acetic & propionic acids as products of carbohydrate metabolism
What are Caries due to?
Microbial fermentations
What is the main bacteria in Dental Caries?
Saccharolyticbacteria (sugar metabolising)- major fermentation end product is lactic acid
What type of relationship does Bacteria have?
Symbiosis- Within biofilm/plaque, different bacteria utilise each other’s products to grow
What does glycolysis do?
Provide energy for the caries to grow?
What is crucial for glycolysis?
Glucose
Which shape form is more active?
Tetramer
- Changes in quaternary structure affects activity
What is the main controller of Glycolysis?
Phosphofructokinase
- Pyruvate kinase also plays a minor role
Describe the shape of Phosphofructokinase
Reversibly dissociates between Tetramer and Dimer
Which state is more active?
R state
What is Co-operativity?
Binding of one molecule of substrate makes it easier for more substrate to bind
What does Co-opertivity increase?
Probability of a conformational change from T-state to R-state
What does F-6-P binding do?
Promotes the transition of PFK from the T to R state – metabolite concentration
What do Allosteric effectors do?
Bind somewhere other than the active site
What is PFK is activated by?
ADP (signals low energy state in cell) – positive allosteric effector
What is PFK inhibited by?
Phosphoenolpyruvate (PEP) – negative allosteric effector AND also feedback inhibition
