Chapitre 1: Organisation de la matière

La présence initiale du dihydrogène dans l'univers a conduit à la formation de tous les éléments connus ajd par :
- la distribution de matière dans l'Univers
- fusion and fission
- radioactivity and half-life of the elements

What is matter?
- physical substance
- can't create or destroy it but you can change it
- has a mass and a volume
- different states of matter
- made of atoms

Hydrogen is the 1st atom ever made, a star is essentially composed of H.

Nuclear Fusion within stars are due to high T and gravitational pressures, produces the necessary light and heat needed by living things on Earth.
→ releases heat and 2 becomes 1 + particle

Nuclear Fission releases neutrons and split appart other atoms (high T and atm pressure needed)
→ releases heat and 1 becomes 2 + neutron (ex: nuclear reactors/bombs)

Radioactive decay:
- unstable elements spontaneously breakdown to form more stable ones
- some radioactive elements have been found in the Earth's crust since its formation
- the half life is the amount of time necessary for half the nuclei in a radioactive sample to breakdown into another element
- radioactivity is random

Measuring radioactivity:
-alpha (paper)
-beta (+ aluminium)
-Y (gama) (+ lead)

Becquerel : SI unit of measurement of radiation (disintegrations.sc^-1)
Sievert (Sv): biological unit for measurement of radiation dose to determine health effects due to low level radiation
Geiger counter: instrument used for detecting and measuring ionizing radiation (clicks.mn^-1)

Final Quantity = Initial quantity (1/2) ^ nombre de half life
or Initial Q = FQ / rest
or time: calculate the number of half lives (ex: 25%: 2), then multiply the half life by this number

A decay graph shows the variation in the number of radioactive atoms in a sample over time.

Isotope: same number of p and e but number of n different

- the sunthesis of heavy elements cannot happen in regular chem reactions as they require a very high T and pressure)

Chapitre 2: Crystals

- a solid form of matter with a repeating geometric shape

granite: crystal mais basalte: verre

- a unit cell is the simplest repeating unit of a crystal
- simple cubic unit cell : all chem parts are identical and located at lattice points (coins du cube) : 1 atom
- face-centered unit cell : all chem parts are identical and located at lattice points and faces of the cube : 4 atoms

Atomic Parking Factor: fraction of the volume of a crystal occupied by constituent parts (atoms)
- simple unit cell (52%)
- face centered unit cell (68%)
= (N particles x V particle) / V unit cell

Macroscopic properties of crystals:
- graphite: conducts electricity
- diamond: very hard, can cut through most substances
- nanotube: man-made, can transform other substances to change their physical properties

minerals: well defined chemical coumpounds usually found in a crystalline state (solids)

amorphous solid: any crystalline solid in which the atoms and molecules are not organized in a definite lattice pattern

représentation ordonnée : crystal (ordered, the ions constituing a crystal are organized in an ordered way)
rep désordonnée: glass (atoms not organized in an ordered and specific way: amorphous solid so glass)

density = mass (of all the atoms!)/ V

Chapitre 3: The Cell

microscope today : compound (2 lenses), magnification up to 960x

cell theory: all living things are made of cells (smallest part of that matter)
→ all living things are made of cells
→ the cell is the smallest unit of life
The specialized structures within cells( organelles) carry out different functions. Organelles cannot survive alone.

→ cells only arise from pre-existing cells
cells multiply through division
mitosis resulsts in genetically identical diploid daugther cells
meiosis generates haploid gametes (sex cells)

Spontaneous generation (appearance of life from non-living matter) vs. Cell Theory:
Louis Pasteur prouve que c'est faux en 1861 (bouillon stérile par chauffage, sans col recourbé en forme de S: contaminé par des microorganismes puis pareil mais avec col: reste stérile)
→ la rupture de la partie supérieur au col permet aux microorganismes de pénétrer dans le flacon, le bouillon se détériore

Evidence for Cell Theory:
→ all known examples of growth be it of a tissue, an organism or a population are all a result of cell division
→ viruses aren't cells but need them to reproduce (can only be produced inside the host cells that they have infected)
→ genetic code is universal (common ancestor)
→ cells are highly complex structures and no mechanism has been found for producing cells from simpler subunits
→no examples in nature that contradicts cell theory

- scales and magnification to estimate size

electron microscope:
→ TEM (transmission electron microscope): electrons pass through a dried out sample
→ SEM (scanning electron microscope): electrons bounce off a sample that had been frozen, cracked and coated with gold

Atomic Force Microscope (AFM): measures interactions gtw 2 surfaces at the atomic scale

mag= measured scale bar (règle) / scale indicated
actual size= measured length / mag

The plasma membrane:

Oil molecules are hydrophobic (fear of water), its droplet stays together and makes a perfect circular shape in fear

Oil molecules are non-polar (no charge)
Water molecules are polar (+ or - charge)

total surface of red blood cells composing the lipids

the plasma membrane (bilayer sheet):

extracellular space

2 rangées :
rond avec une patte droite et une patte cassée aux 3/4 (à droite)
pareil mais 180 degrés

zoom: encadrer 1phospholipid : pareil mais avec la tête en bleu et en plus gros (hydropolic head) et autre flèche (hydrophobic tail), entre les 2 pattes: rond jaune (glycérol) + phospholipid en bas à gauche du cadre

Lumen of Cell

the head is hydrophillic (polar phosphate head)
the tail is hydrophobic (long non-polar lipid tails)

Liposome: cercle avec têtes à l'ext et intérieur
Micelle: cercle avec têtes que à l'ext

Histoire du Microscope:
invention du 1er microscope: revendiqué par Jessen en 1595 (lunetier hollandais)
observation de cellules vivantes pour la 1e fois en 1660 par Leewenhoek mais aussi en 1665 observation de cellules de Liège par Robert Hooke
observation d'animalcules (animal microscopique qui vit dans l'eau) en 1675 par Leeuwenhoek

invention du microscope:
→ identification d'une structure commune à tous les ê vivants)

les apports de la microscopie électronique ont permis de préciser la théorie cellulaire en ajoutant la présence d'une membrane délimitant la cellule de son environnement et lui permettant d'intéragir avec celle-ci & l'ADN comme support universel des informations génétiques