overview Flashcards
(95 cards)
1
Q
What is the acid dissociation constant Ka?
A
Measure of the strength of an acid
2
Q
What does a large dissociation constant (Ka) and low pKa suggest?
A
Strong acid
3
Q
What does a high pKa indicate?
A
Weak acid
4
Q
What is the main acid involved in tooth decay?
A
Lactic acid
5
Q
What is the Henderson-hasslebalch equation?
A
PH= pKa + log10 (base/acid) - FOR WEAK ACIDS
6
Q
When do buffers have greatest buffering capacity?
A
When 50% dissociated eg pKa=pH
7
Q
What is the main buffer and other buffers in saliva?
A
- BICARBONATE HCO3-
- phosphate
- histatin proteins (rich in histidine)
8
Q
What is the pH of blood?
A
7.4
9
Q
What is electronegativity?
A
Power of an atom to attract electrons to itself
10
Q
What are gap junctions?
A
- direct contact between cells for electrical transmission
- allow current to flow between cells
11
Q
What is the difference between neural communication and hum oral communication?
A
Neural
- specific and localised
- quick/rapid response
Humoral
- body-wide
- slow response
- persistent
12
Q
Which type of hormones can enter the cell?
A
Steroid hormones
13
Q
Can peptide transmitters enter the cell?
A
Yes
14
Q
What is the most common second messenger?
A
Ca2+ ions
(CAMP)
15
Q
What does adenyl cyclase do?
A
Converts ATP to cAMP in the cytosol
16
Q
Sequence of cAMP as second messenger?
A
- transmitter binds to membrane receptor
- G-proteins activated
- ATP to cAMP by adenyl cyclase
- cAMP activates protein kinase
- chemical reaction
17
Q
Sequence of Ca2+ as second messenger?
A
- transmitter binds to membrane receptor
- G proteins activated
- activates phospholipase C
- opens Ca2+ channels, Ca2+ influx by diffusion
- binds to a protein
- chemical reaction
18
Q
What is an enzyme?
A
Biological catalyst
19
Q
What are two examples of enzymes in saliva?
A
- amylase
- maltase
20
Q
What is standard free energy G and activation energy Ea?
A
21
Q
What is the effect of an enzyme on activation energy?
A
Lowers it
22
Q
What is Vmax?
A
The max rate of reaction
23
Q
What is Km?
A
Affinity (inverse measurement)
- low Km= saturated with substrate
- high Km= non saturated
24
Q
Which type of inhibitor can be reversed via increasing substrate concentrations?
A
Competitive
25
Optimum pH of trypsin?
7
26
Optimum pH of pepsin?
3
27
What is negative feedback control?
Counteracts the change
28
What is feedforward control?
Altering a behaviour before the signal eg stopping eating before full
29
What is positive feedback?
Change acts to increase that change
30
What is a drug?
Chemical substance which effects the function of the body
31
How would you take a sample of angular cheilitis?
Moist swab
32
What is an example of a non-selective anger?
Blood agar
33
What is an example of a selective agar?
Mannitol salt sugar
34
What three organelles do both prokaryotes and eukaryotes have in common?
- DNA
- cell membrane
- ribosomes
35
What is the method bacterial cells use to attach to host?
Pili
36
Gram stain reaction stages?
- film
- crystal violet
- all cells dyed violet
- iodine
- all cells blue-black
- acetone
- gram negative are decolourised
- red dye
- gram positive blue-black, gram negative red
37
what is an example of an endotoxin?
Prevotella intermedia
38
What are examples of two bacteria’s which cause periodontitis?
- P gingivalis
- Prevotella intermedia
39
Gram positive cocci bacteria and effect?
- streptococcus mutants- dental caries
- staphylococcus aureus- angular cheilitis
40
Gram negative cocci and effect?
Neisseria meningititdis- meningitis
41
Gram positive bacilli and effect?
Clostridium tetanii
- tetanus
42
Gram negative bacilli and effect?
Prevotella intermedia- periodontitis
43
What does ubiquitous mean?
Multiple environments
44
What is the main caries causing bacteria?
Streptococcus mutants
45
What are the 4 aetiological factors for dental caries?
- plaque
- sugar
- time
- tooth
46
What causes denture stomatitis?
Candida
47
What an examples of an encapsulated infection?
Meningitis
48
What is the function of a capsule?
Protection from immune invasion
49
Where are exotoxins released from?
Inside gram positive bacteria
50
Where are endotoxins released from?
Cell wall of gram negative bacteria
51
What are the four categories of cell chemical signalling?
- autocrine
- paracrine
- endocrine
- gap junctions
52
What type of molecules can diffuse through a cell membrane?
Hydrophobic
53
What are the three distinct stages of cell communication?
- ligand binds to receptor
- signal transduction
- cell response
54
What are the three classes of membrane receptors?
- G coupled (second messengers)
- enzyme linked (phosphorylation)
- ion channel (action potential)
55
Describe cell signalling in type 1 diabetes
LOSS OF SIGNAL
- insulin producing cells are destroyed
- receptor isn’t activated
- no transduction
- no glucose uptake
56
What is the treatment for type 1 diabetes?
Replenish insulin
57
Describe cell signalling gin type 2 diabetes
TARGET IGNORES SIGNAL
- insulin binds to receptor
- receptor isn’t activated
- no transduction
- weakened response
58
What is the treatment for type 2 diabetes?
Diet and exercise to regulate blood glucose
59
What are the functions of DNA/RNA?
- direct synthesis of proteins
- transmit genetic information
60
What are the two strands of DNA held together by?
Hydrogen bonds
61
What replaces thymine in RNA?
Uracil
62
How many strands is RNA?
Single
63
What happens during protein synthesis?
Transcription: RNA polymerase copies DNA strand to make mRNA (nucleus)
Translation: mRNA translated by tRNA using ribosome (cytoplasm)
64
What are the three effects of substitution?
- conservative mutation
- non-conservative mutation
- no mutation
65
What does insertion or deletion of a base cause?
Frame-shift mutation
66
What is sickle cell anaemia an example of?
Single base substitution, replacing amino acid glutamic acid with valine
67
What is an example of a capsulated yeast?
Cryptococcus
68
What is the structure of collagen?
Triple helix
69
How many chains does myoglobin have?
1
70
How many chains does haemoglobin have?
4
71
What are examples of messenger proteins?
- insulin
- growth hormone
- glucagon
72
What type of protein is myosin?
Fibrous
73
What type of protein is actin?
Globular
74
What is an example of a monosaccharide?
Glucose
75
What are examples of polysaccharides?
Starch
Glycogen
Cellulose
76
What is the pH of saliva?
6.2-7.2
77
How to calculate pH from hydrogen ion concentration?
Ph= -log10(H)
78
What is a buffer?
A solution which can resist changes in pH when acid or base is added
79
When are buffers most effective?
At 50% dissociation
80
What is the body substance with the highest mineral content?
Enamel
81
What is the mineral content in enamel vs dentine?
95% in enamel
70% in dentine
82
What is the name of the mineral component of teeth and bones?
Hydroxyapatite
83
What is the difference between erosion acid and caries acid?
- erosion involves acid from the diet
- caries involves acid from plaque bacteria
84
How is fluoride incorporated into hydroxyapatite?
OH- ions replaced by F- ions which are smaller to fit into the crystal better making it more stable and less soluble to acid
85
What are the three ways in which fluoride acts?
- reduces enamel solubility
- inhibits bacterial metabolism of carbohydrates
- promotes enamel remineralisation by saliva
86
What are the viral replication stages?
- attachment
- penetration
- uncoating
- synthesis of viral components
- assembly
- release
87
What are the three possible effects of a virus on a cell?
- cell death- cytopathic
- transformation- changed to a cancerous cell
- latent infection- no effect
88
What are ways in which the viral can be transmitted?
- inhalation
- ingestion
- inoculation (skin)
- congenital (mum to foetus)
- sexually transmitted
89
Structure of influenza virus
- haemagglutinin
- neuroaminidase
90
What is vCJD and. Why is it important?
- neurological disease (TSE classified)
- can be difficult to clean as its an infectious agent
- long incubation period
- asymptomatic carriers
91
What is the definition of a biofilm?
Matrix enclosed bacterial populations adherent to each other and or to surfaces
92
What are benefits of being a biofilm?
- protective
- coordinated cellular events
- labour division
- less energy use
- survival in numbers
93
Oral biofilm diseases?
- caries
- endodontic infection
- periodontal infection
- mucosal infection
94
Equation for V (rate of reaction)?
V=Vmax(S)/(Km+S)
95
What is Km?
substrate concentration when V=halfVmax
