Chapter 2Chapter 2The Chemistry of Life

The 4 organic molecules found in living things

The 4 organic molecules found in living things

1. Carbohydrates = C-H-O2. Lipids = C-H-O3. Nucleic Acids = P-C-H-O4. Proteins = N-H-O-C

ChemistryChemistryWhat is the chemistry of “life”?

Twenty-five chemicals are necessary for life and four create about 96 % of living matter: 1.Carbon2.Oxygen3.Hydrogen4.Nitrogen.

COHN

The Atom and Periodic Tablehttp://www.classzone.com/books/earth_science/terc/content/investigations/es0501/es0501page01.cfm

AtomsAtomsDemocritus coined the term atom 2500 years ago

What is an atom made of?What is atomic number?What is atomic mass?

Electrons, Protons, Neutrons# of protonsAverage number of protons & neutrons

Isotopes & Element

Isotopes & Element

Isotope - different number of neutrons

Do isotopes act differently in chemical reactions?

How are radioactive isotopes used?(Geological Dating, Bacteria, Cancer, Tracers or Markers)

What is an element?1. An material which cannot be broken down or changed into another substance using chemical means. The basic chemical building blocks of matter.

What makes elements different from each other?2. The number of protons in the nucleus

Forces of NatureForces of Nature4 Forces1. Electromagnetism2. Strong or Nuclear Force between protons & neutrons3. Weak – decay of an atom (alpha, beta, gamma) 4. Gravity – the force exerted between two objects

God Particlehttp://www.economist.com/node/21541797

RadioactiveDecay

RadioactiveDecay

1. Alpha Decay alpha particle emitted = (2 protons and 2

neutrons)

2. Beta Decay

A . Beta Minus - Neutron turns into a proton + electron + antineutrino – Last two emiited

B. Beta Plus - Neutron turns into a proton + positron + neutrino – last two emitted

3. Gamma Decay – nucleus emits photons Nucleus moving from high to lower state of energy

Compounds & BondsCompounds & BondsCompounds - two or more elements chemically bonded

Molecule - smallest unit of a compound that is still exhibiting the compounds properties

Valence Electrons - form bonds – what is stable?

Ionic Bonds - transfer of electrons - resulting in ions

Covalent Bonds - shared electrons

Van der Waals ForcesVan der Waals ForcesVariances in charges causing attraction & weak bonds

Geckos and surface area in their feet

WaterWaterWhat makes water so great?

Hydrogen Bondinghttp://www.youtube.com/watch?v=lkl5cbfqFRM&feature=related

Properties of Water – Blue Planet – ever wonder why?Properties of Water – Blue Planet – ever wonder why?DensityPolarityHydrogen BondsHigh Specific Heat Capacity: 1g H2O/1degree celsiusCohesionAdhesionUniversal Solvent

Mixture - two or more elements not chemically combined1. Solution - Universal Solvent - ions disperse2. Suspensions - blood - movement keeps larger

particles afloat throughout the fluid

pH - "Potential Hydrogen”pH - "Potential Hydrogen”

What is the pH scale? A scale from 0 to 14 reflecting the concentration of hydrogen ions in solution; pure water has a pH value of 7, acids have a lower value and bases higher.

• pH levels affect the conformational state (optimum 3D formation) of the enzyme.

What is an acid and what is a base?Acids are compounds that contain hydrogen and can dissolve in water to release hydrogen ions into solution.HCl disolved in H2O = H+(aq)  +  Cl-(aq)

Bases are compounds that dissolve in water to release hydroxide ions (OH-) into solution.NaOH disolved in H2O = Na+(aq)  +  OH-(aq)

What is a buffer? A buffer solution is one which resists changes in pH when small quantities of an acid or a base are added to it.

pH & BloodpH & BloodYour blood's pH is normally at 7.4• Lungs – carbon dioxide (CO2)• Kidneys - bicarbonate (HCO3

) ammonia (NH3) / ammonium (NH4+)

Alkalosis• pH rises above 7.45 • Too Little CO2 & Too Much HCO3

• Associated with electrolyte disturbances caused by prolonged vomiting, severe dehydration, or hyperventilation• Body interprets low carbonic acid concentrations as a sign of high oxygen concentrations, so it constricts blood vessels to reduce oxygenation.

Acidosis• pH falls below 7.35 • Too much CO2 & Too Little HCO3

• Body interprets high carbonic acid concentrations as a sign of low oxygen concentrations, so it dilates blood vessels to improve oxygenation.

•The HCO3/CO2 buffer system is extremely important because it can be rapidly readjusted in alkalosis and acidosis1. H+(aq) + HCO3

-(aq) ↔ H2CO3(aq) 2. CO2(aq) + H2O(l) ↔ H2CO3(aq)