Chemical foundations of life

Question 1

Atomic number

Answer 1

nb of protons in an element’s nucleus (en haut)

Question 2

Atomic mass

Answer 2

nb of protons & neutrons in an elements nucleus (en bas)

Question 3

n

Answer 3

level number

Question 4

x

Answer 4

orbital type (s2, p6, d10, f14)

Question 5

e

Answer 5

nb of electrons in a particular level

Question 6

Valence level

Answer 6

Most external layer occupied by electrons (the ones that participate in the chemical bonds)

Question 7

Electronegativity

Answer 7

the tendency of an atom to attract electrons (of other compounds) towards itself to create a chemical bond

Question 8

Primary bioelements

Answer 8

Chemical elements that account for 99% of celluar mass C, H, O, N, P, S

Question 9

Bulk elements

Answer 9

structural elements of cells and tissues. Required diet uptake in gram quantities daily (H, C, N, O, Na, P, S, Cl, K, Ca)

Question 10

Trace elements

Answer 10

Required diet uptake in milligrams daily (Mg, V, Cr, Mn, Fe, Co, Ni, Cu, Zn…)

Question 11

Inorganic biomolecules

Answer 11

Bioelements joined by ionic bonds. Salts, water.

Question 12

Organic biomolecules

Answer 12

Bioelements joined by covalent bonds. Carbohydrates, lipids, proteins, nucleotides.

Question 13

Mineral elements related with teeth

Answer 13

Calcium and phosphate as hydroxyapatite and calcium phosphate in enamel, dentin and cementum.
Magnesium in enamel and dentin.
Fluoride most electronegative: Enamel hardness.

Question 14

Mineral elements related with saliva

Answer 14

Phosphate works as a buffer for saliva pH maintenance.
Calcium, phosphate magnesium ions in the saliva for enamel maturation process.
Phosphorus, calcium and fluoride: Remineralization

Question 15

Fluoride good effects

Answer 15

Reduces apatite solubility in acids by an isomorphic replacement of hydroxide ions with fluoride ions to form fluoroapatite.
Incorporates into bacterial biofilms to inhibit enolase (enzyme that inhibits glycolysis)

Question 16

Fluoride bad effects

Answer 16

Inhibition of enzyme activity
Inhibition of ameloblasts
Enamel florisis

Question 17

Types of chemical bonds

Answer 17

Covalent bonds (polarized, non polarized)
Non covalent bonds( Ionic, metallic)

Question 18

Ionic bond characteristics

Answer 18

Very different electronegativity between atoms.
Between metals and non metals.
Electrostatic forces.
Ex: NaCl

Question 19

Covalent bond characteristics

Answer 19

High and very similar electronegativity between atoms.
Between non metals.
Ex: H2O

Question 20

Metallic bonds characteristics

Answer 20

Low and very similar electronegativity between atoms.
Between metals.
Ex: Fe

Question 21

Polar bond

Answer 21

Elements with different electronegativity.
Asymmetrically shared electrons.
Electrons closer to the most electronegative element.

Question 22

Non polar bond

Answer 22

Elements with similar electronegativity.

Shared electrons distributed equally.

Question 23

Inorganic biomolecules

Answer 23

Water
Mineral inorganic salts
Oxygen
Oligoelements
Carbon dioxide

Question 24

Organic biomolecules

Answer 24

Carbohydrates
Lipids
Proteins
Nucleic acids

Question 25

Organic components of dental tissues

Answer 25

``` -Proteins: Collagens mainly type 1 Proteoglycans and glycoproteins -Carbohydrates: Dextrans and bacterial products on the enamel surface ```

Question 26

Dental pulp composition

Answer 26

``` 75% water 25% Organic matter Collagen 1 3 5 6 Proteoglycans Fibronectin Sialoprotein (organic tissue matrix protein) BMPs Metalloproteinases (enzyme) Growth factors ```

Question 27

Enamel composition

Answer 27

``` 96% hydroxyapatite 1% organic matter 3% water Low protein concentration Glucoproteins Metalloproteinases ```

Question 28

Dentin composition

Answer 28

70% hydroxyapatite 18% organic matter 12% water Collagen 1 3 5

Question 29

Cementum composition

Answer 29

``` 50% hydroxyapatite 22% organic matter calcified 32% water Collagen 1 Proteoglycans Glucosaminoglycans Glucoproteins ```

Question 30

Hydroxyapatite

Answer 30

Produced by ameloblasts | Form of crystalline phosphate Ca10(PO4)6(OH)2

Question 31

Fluoroapatite

Answer 31

More stable and less soluble than hydroxyapatite

Question 32

Range of solubility of hydroxyapatite and fluoroapatite

Answer 32

Fluorapatite (pH=4,5) < Hydroxyapatite (pH=5,5)

Question 33

Different type of interactions between biomolecules

Answer 33

- Electrostatic - Hydrogen bonding - Van der Walls forces - Hydrophobic intereactions

Question 34

Non covalent interactions between molecules

Answer 34

Molecules are elecronegatively neutral And establish cohesive forcces of electrostatic nature The 4 types of interactions between two electric dipoles of opposite sign (next)

Question 35

Different types of weak interactions between biomolecules

Answer 35

- Electrostatic or ionic - Hydrogen bonding - Van der Walls forces - Hydrophobic intereactions

Question 36

Hydrogen bonding is formed between:

Answer 36

- an electronegative aton (Hydrogen acceptor, usually oxygen or nitrogen) - a hydrogen atom covalently bonded to an other electronegative atom (H donor)

Question 37

Hydrogen bonds in liquid water:

Answer 37

- are attractions between the protons of the oxygen nuclei. - are attractions between two hydrogen atoms. - are attractions between the H+ and OH– ions of the liquid. - are ion-induced dipole attractions. - are dipole-dipole attractions.

Question 38

Van der Walls interacions

Answer 38

Weak interatomic interaccions between two very close uncharged atoms with their surrounding electons influence eachother, if there is a random variation in the positions of the electrons it may create an electric dipole

Question 39

Van der walls radius

Answer 39

Mesure of how close the atom will allow to approach one another in Van der Walls interacions. (in nm)

Question 40

Hydrophobic interactions

Answer 40

Between amphipatic molecules (compounds containing a polar and a nonpolar region)

Question 41

The most stable biomolecule structure

Answer 41

``` Wear interactions maximized. -Tridimensional structure of biomolecules -Binding of Antigen-antibody -Binding of hormone-receptor -Binding of neurotrasnmitter-receptor ```

Question 42

Strong interactions

Answer 42

Intramolecular covalent bonds: Disulfure bridges