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Oral Biology (Oral Cavity) > Proteins of Biomineralisation > Flashcards

Flashcards in Proteins of Biomineralisation Deck (31)
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1

Give examples of bio minerals

- Calcium Carbonate
- Calcium Phosphate
- Silica
- Iron Oxides
- Metal sulphides

2

What controls the inorganic crystal growth in biomineral structures

Organic molecules like proteins

3

When are ameloblasts no longer present in the tooth

After the tooth erupts

4

When are odontoblasts no longer present in the tooth

HAHAHAHAH slag they're still alive in a completely developed tooth

5

What crystals are present in enamel and how are they arranged

Hydroxyapatite crystals in prisms, rows of enamel prisms are often organised perpendicular to each other.

6

What are the stages of amelogenesis

Pre-Secretory
Secretory
Transition
Maturation

7

What happens in the pre-secretory stage of amelogenesis

- IEE cells develop and elongate into pre-ameloblasts
- Ameloblasts develop a Tomes' process

8

Roughly how mineralised is the enamel in the secretory stage

30% wish

9

How many proteins are left in the enamel after maturation

Pretty much none

10

What is different in enamel matrix compared to any other mesenchymal mineralised tissue

It doesn't contain any collagen

11

What is the main component of the developing enamel ECM

90% amelogenin

12

What genes is the amelogenin gene found

X and Y

13

What does an Amelogenin protein bind to in the enamel tissue

Onto hydroxtapatite crystals

14

What does an Amelogenin protein bind to in the enamel tissue

Onto hydroxyapatite crystals

15

What post-translational modifications happen to amelogenin

No Glycosylation
Some phosphorylation: series to phosphoserines

16

What allows growth of enamel crystals to only happen on the c-axis during the secretory phase

Amelogenins bind to proton-enamel crystals on the a and b faces of the crystals. This prevents growth in these faces and only allows growth on the c axis

17

When can growth occur on the a and b faces of enamel crystals

During maturation when amelogenin proteins are lost

18

What AAs are there a lot on in amelogenin

Proline and Glutamic Acid

19

What are the beta-sheets in amelogenin thought to be used for

Ca2+ channels

20

Name some other proteins found in the enamel matrix

- Enamelin - 5-10% of matrix
- Tuftelin - Located mainly at DEJ, secreted before amelogenin
- enzymes
- serum albumins - do not bind to crystals
- proline rich proteins

21

What can happen to enamel in amelogenesis imperfecta, just name the hypo-things like you know ffs idk

Hypoplastic
Hypocalcified
Hypomaturated
(Its X-linked)

22

What is different in the enamel matrix of normal enamel and AI enamel

More proteins in AI enamel that normal, so less mineralisation

23

Describe the structure of Type 1 collagen

- High proline triple helix
- Proline ring sticks outwards
- Glycine every 3rd residue
- Stabilised by interchain hydrogen bonds

24

Theres quite a lot of collagen in dentine, how can this be related to mineralisation

HAP crystals form in the gaps within collagen fibres between the triple helices of collagen

25

Name some dentin specific non-collagenous proteins

Phosphophoryns
Dentin Sialoprotein (DSP)
AG1

26

What are the signs and symptoms of dentinogenesis imperfecta

- blue sclerae
- increased incidence of bone fractures
- abnormally soft dentin, undergoes rapid and severe functional attrition
- obliterated pulpal chamber
- Enamel is normal but fractures/chips easily
- Dentin tubules are disoriented, irregular and widely spaced

27

What is primary dentin and name some features

Outlines pulp chamber and makes the main part of the dentin mass. Mantle dentin is the outer layer of the primary dentin, slightly less mineralised. Circumpulpal dentin is also primary dentin but is the inner layer.

28

When does primary odontogenesis stop and secondary begin

Primary - until tooth becomes functional or until root apex is closed
Secondary - after primary, continues at slower rate

29

Difference between primary and secondary dentin

Secondary = more irregular in structure and sometimes less mineralised than primary dentin

30

What is the intertubular dentin

Intertubular dentin is formed by odontoblasts through predentin mineralisation - dense collagen matrix