overview Flashcards

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1
Q

What is the acid dissociation constant Ka?

A

Measure of the strength of an acid

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2
Q

What does a large dissociation constant (Ka) and low pKa suggest?

A

Strong acid

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3
Q

What does a high pKa indicate?

A

Weak acid

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4
Q

What is the main acid involved in tooth decay?

A

Lactic acid

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5
Q

What is the Henderson-hasslebalch equation?

A

PH= pKa + log10 (base/acid) - FOR WEAK ACIDS

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6
Q

When do buffers have greatest buffering capacity?

A

When 50% dissociated eg pKa=pH

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7
Q

What is the main buffer and other buffers in saliva?

A
  • BICARBONATE HCO3-
  • phosphate
  • histatin proteins (rich in histidine)
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8
Q

What is the pH of blood?

A

7.4

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9
Q

What is electronegativity?

A

Power of an atom to attract electrons to itself

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10
Q

What are gap junctions?

A
  • direct contact between cells for electrical transmission
  • allow current to flow between cells
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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

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12
Q

Which type of hormones can enter the cell?

A

Steroid hormones

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13
Q

Can peptide transmitters enter the cell?

A

Yes

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14
Q

What is the most common second messenger?

A

Ca2+ ions
(CAMP)

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15
Q

What does adenyl cyclase do?

A

Converts ATP to cAMP in the cytosol

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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
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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
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18
Q

What is an enzyme?

A

Biological catalyst

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19
Q

What are two examples of enzymes in saliva?

A
  • amylase
  • maltase
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20
Q

What is standard free energy G and activation energy Ea?

A
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21
Q

What is the effect of an enzyme on activation energy?

A

Lowers it

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22
Q

What is Vmax?

A

The max rate of reaction

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23
Q

What is Km?

A

Affinity (inverse measurement)
- low Km= saturated with substrate
- high Km= non saturated

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24
Q

Which type of inhibitor can be reversed via increasing substrate concentrations?

A

Competitive

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25
Q

Optimum pH of trypsin?

A

7

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26
Q

Optimum pH of pepsin?

A

3

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27
Q

What is negative feedback control?

A

Counteracts the change

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28
Q

What is feedforward control?

A

Altering a behaviour before the signal eg stopping eating before full

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29
Q

What is positive feedback?

A

Change acts to increase that change

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30
Q

What is a drug?

A

Chemical substance which effects the function of the body

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31
Q

How would you take a sample of angular cheilitis?

A

Moist swab

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32
Q

What is an example of a non-selective anger?

A

Blood agar

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33
Q

What is an example of a selective agar?

A

Mannitol salt sugar

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34
Q

What three organelles do both prokaryotes and eukaryotes have in common?

A
  • DNA
  • cell membrane
  • ribosomes
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35
Q

What is the method bacterial cells use to attach to host?

A

Pili

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36
Q

Gram stain reaction stages?

A
  • 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
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37
Q

what is an example of an endotoxin?

A

Prevotella intermedia

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38
Q

What are examples of two bacteria’s which cause periodontitis?

A
  • P gingivalis
  • Prevotella intermedia
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39
Q

Gram positive cocci bacteria and effect?

A
  • streptococcus mutants- dental caries
  • staphylococcus aureus- angular cheilitis
40
Q

Gram negative cocci and effect?

A

Neisseria meningititdis- meningitis

41
Q

Gram positive bacilli and effect?

A

Clostridium tetanii
- tetanus

42
Q

Gram negative bacilli and effect?

A

Prevotella intermedia- periodontitis

43
Q

What does ubiquitous mean?

A

Multiple environments

44
Q

What is the main caries causing bacteria?

A

Streptococcus mutants

45
Q

What are the 4 aetiological factors for dental caries?

A
  • plaque
  • sugar
  • time
  • tooth
46
Q

What causes denture stomatitis?

A

Candida

47
Q

What an examples of an encapsulated infection?

A

Meningitis

48
Q

What is the function of a capsule?

A

Protection from immune invasion

49
Q

Where are exotoxins released from?

A

Inside gram positive bacteria

50
Q

Where are endotoxins released from?

A

Cell wall of gram negative bacteria

51
Q

What are the four categories of cell chemical signalling?

A
  • autocrine
  • paracrine
  • endocrine
  • gap junctions
52
Q

What type of molecules can diffuse through a cell membrane?

A

Hydrophobic

53
Q

What are the three distinct stages of cell communication?

A
  • ligand binds to receptor
  • signal transduction
  • cell response
54
Q

What are the three classes of membrane receptors?

A
  • G coupled (second messengers)
  • enzyme linked (phosphorylation)
  • ion channel (action potential)
55
Q

Describe cell signalling in type 1 diabetes

A

LOSS OF SIGNAL
- insulin producing cells are destroyed
- receptor isn’t activated
- no transduction
- no glucose uptake

56
Q

What is the treatment for type 1 diabetes?

A

Replenish insulin

57
Q

Describe cell signalling gin type 2 diabetes

A

TARGET IGNORES SIGNAL
- insulin binds to receptor
- receptor isn’t activated
- no transduction
- weakened response

58
Q

What is the treatment for type 2 diabetes?

A

Diet and exercise to regulate blood glucose

59
Q

What are the functions of DNA/RNA?

A
  • direct synthesis of proteins
  • transmit genetic information
60
Q

What are the two strands of DNA held together by?

A

Hydrogen bonds

61
Q

What replaces thymine in RNA?

A

Uracil

62
Q

How many strands is RNA?

A

Single

63
Q

What happens during protein synthesis?

A

Transcription: RNA polymerase copies DNA strand to make mRNA (nucleus)
Translation: mRNA translated by tRNA using ribosome (cytoplasm)

64
Q

What are the three effects of substitution?

A
  • conservative mutation
  • non-conservative mutation
  • no mutation
65
Q

What does insertion or deletion of a base cause?

A

Frame-shift mutation

66
Q

What is sickle cell anaemia an example of?

A

Single base substitution, replacing amino acid glutamic acid with valine

67
Q

What is an example of a capsulated yeast?

A

Cryptococcus

68
Q

What is the structure of collagen?

A

Triple helix

69
Q

How many chains does myoglobin have?

A

1

70
Q

How many chains does haemoglobin have?

A

4

71
Q

What are examples of messenger proteins?

A
  • insulin
  • growth hormone
  • glucagon
72
Q

What type of protein is myosin?

A

Fibrous

73
Q

What type of protein is actin?

A

Globular

74
Q

What is an example of a monosaccharide?

A

Glucose

75
Q

What are examples of polysaccharides?

A

Starch
Glycogen
Cellulose

76
Q

What is the pH of saliva?

A

6.2-7.2

77
Q

How to calculate pH from hydrogen ion concentration?

A

Ph= -log10(H)

78
Q

What is a buffer?

A

A solution which can resist changes in pH when acid or base is added

79
Q

When are buffers most effective?

A

At 50% dissociation

80
Q

What is the body substance with the highest mineral content?

A

Enamel

81
Q

What is the mineral content in enamel vs dentine?

A

95% in enamel
70% in dentine

82
Q

What is the name of the mineral component of teeth and bones?

A

Hydroxyapatite

83
Q

What is the difference between erosion acid and caries acid?

A
  • erosion involves acid from the diet
  • caries involves acid from plaque bacteria
84
Q

How is fluoride incorporated into hydroxyapatite?

A

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
Q

What are the three ways in which fluoride acts?

A
  • reduces enamel solubility
  • inhibits bacterial metabolism of carbohydrates
  • promotes enamel remineralisation by saliva
86
Q

What are the viral replication stages?

A
  • attachment
  • penetration
  • uncoating
  • synthesis of viral components
  • assembly
  • release
87
Q

What are the three possible effects of a virus on a cell?

A
  • cell death- cytopathic
  • transformation- changed to a cancerous cell
  • latent infection- no effect
88
Q

What are ways in which the viral can be transmitted?

A
  • inhalation
  • ingestion
  • inoculation (skin)
  • congenital (mum to foetus)
  • sexually transmitted
89
Q

Structure of influenza virus

A
  • haemagglutinin
  • neuroaminidase
90
Q

What is vCJD and. Why is it important?

A
  • neurological disease (TSE classified)
  • can be difficult to clean as its an infectious agent
  • long incubation period
  • asymptomatic carriers
91
Q

What is the definition of a biofilm?

A

Matrix enclosed bacterial populations adherent to each other and or to surfaces

92
Q

What are benefits of being a biofilm?

A
  • protective
  • coordinated cellular events
  • labour division
  • less energy use
  • survival in numbers
93
Q

Oral biofilm diseases?

A
  • caries
  • endodontic infection
  • periodontal infection
  • mucosal infection
94
Q

Equation for V (rate of reaction)?

A

V=Vmax(S)/(Km+S)

95
Q

What is Km?

A

substrate concentration when V=halfVmax