Chemistry of LifeChemistry of Life

CarbonCarbonCarbon has four valence electrons Carbon has four valence electrons which results in 4 covalent bonds.which results in 4 covalent bonds.

HydrogenHydrogenHydrogen has only one electron and has Hydrogen has only one electron and has only one covalent bond. only one covalent bond.

OxygenOxygenOxygen has 6 valence electrons but 4 Oxygen has 6 valence electrons but 4 are bound up in two lone pairs leaving are bound up in two lone pairs leaving only 2 single bonding electrons. only 2 single bonding electrons.

NitrogenNitrogenNitrogen has 5 valence electrons but 2 Nitrogen has 5 valence electrons but 2 are bound in a lone pair leaving 3 are bound in a lone pair leaving 3 covalent bond electrons. covalent bond electrons.

Organic Organic CompoundsCompounds

Compounds that Compounds that contain carboncontain carbon

Types: Types: 1. Carbohydrates1. Carbohydrates 2. Lipids2. Lipids 3. Proteins3. Proteins 4. nucleic acids4. nucleic acids

Inorganic Inorganic CompoundsCompounds

Compounds that generally Compounds that generally do not contain carbon atomsdo not contain carbon atoms

ExamplesExamples Salt, water, rust Salt, water, rust * Some inorganic compounds * Some inorganic compounds

also contain carbon; for also contain carbon; for example carbon monoixde, example carbon monoixde, carbon dioxide, and some carbon dioxide, and some minerals.minerals.

Organic Organic ChemistryChemistry

The number of organic compounds number The number of organic compounds number 500,000 and about 2,000 more are added 500,000 and about 2,000 more are added each year. each year. Organic chemistry is the study of compounds Organic chemistry is the study of compounds made primarily from carbon.made primarily from carbon.These compounds have unique properties These compounds have unique properties based on the fact that carbon can bond to based on the fact that carbon can bond to itself covalently almost indefinitely.itself covalently almost indefinitely.The most important aspect of the atoms in The most important aspect of the atoms in organic chemicals are their valence organic chemicals are their valence electrons. electrons.

Molecule BuildingMolecule BuildingMonomersMonomers: small : small building blocks building blocks moleculesmolecules

“ “ one- part”one- part”

Monomers covalently Monomers covalently link to make larger link to make larger moleculesmolecules

PolymersPolymers: molecules : molecules formed by linking two or formed by linking two or more monomersmore monomers

“ “ many parts”many parts”

Polymers made of Polymers made of thousands of monomers thousands of monomers are are macromoleculesmacromolecules

Making and Breaking Making and Breaking PolymersPolymers

Organisms use Organisms use chemical reactions to chemical reactions to make and break make and break covalent bonds of covalent bonds of macromoleculesmacromolecules

CarbohydratesCarbohydratesComposed: Carbons, Hydrogen,Composed: Carbons, Hydrogen,

OxygenOxygen

Molecules are in a 1:2:1 ratioMolecules are in a 1:2:1 ratio * For every carbon there is 2 * For every carbon there is 2 hydrogens and one oxygenhydrogens and one oxygen

Monomer: monosaccharidesMonomer: monosaccharides

Polymer: PolysaccharidesPolymer: Polysaccharides

Carbohydrate Carbohydrate UsesUses

most organisms use most organisms use carbohydrates as an carbohydrates as an energy sourceenergy source

For example:For example:Plants make woody Plants make woody materials for support.materials for support.Insects have a hard outer Insects have a hard outer covering called chitin.covering called chitin.

LipidsLipidsNonpolar molecules Nonpolar molecules that are not soluble that are not soluble in waterin waterComposed of Carbon, Composed of Carbon, HydrogenHydrogen

Types of LipidsTypes of Lipids

FatsFats PhospholipidsPhospholipids WaxesWaxes SteroidsSteroids

ProteinsProteins

ProteinsProteinsAmino AcidsAmino AcidsProteins are composed of Proteins are composed of Carbon, Hydrogen, Oxygen, Carbon, Hydrogen, Oxygen, and Nitrogenand Nitrogen

20 different amino acids 20 different amino acids combine in different 3 combine in different 3 dimensional shapes to make a dimensional shapes to make a LARGE variety of different LARGE variety of different proteins with a HUGE variety of proteins with a HUGE variety of different functionsdifferent functions

Nucleic AcidsNucleic Acids

Nucleic AcidsNucleic AcidsHereditary informationHereditary information

Essential to lifeEssential to life

Monomer: NucleotideMonomer: NucleotidePolymers: DNA and RNAPolymers: DNA and RNA

WaterWaterEssential part of living Essential part of living thingsthings

- live only 6 days - live only 6 days without itwithout itLive for 2 weeks Live for 2 weeks without food.without food.70% of body made of 70% of body made of waterwater

Polarity of Water Polarity of Water MoleculesMolecules

Oxygen's 8 (+)s vs. hydrogen's 2 means Oxygen's 8 (+)s vs. hydrogen's 2 means oxygen has a stronger attraction for oxygen has a stronger attraction for electrons.electrons.

The molecule has a bent shape as a The molecule has a bent shape as a result and the oxygen end has a slight result and the oxygen end has a slight (-) charge so hydrogen end has a …..(-) charge so hydrogen end has a …..

Properties of Properties of Water Water

What we know.What we know.Turns to a solid at 0°C Turns to a solid at 0°C

Vapor at 100°C. Vapor at 100°C.

Density = 1 gram per cubic centimeter (1 g/cmDensity = 1 gram per cubic centimeter (1 g/cm33))

Neutral - 10 protons, 10 electrons totalNeutral - 10 protons, 10 electrons total

pH = 6.9996 = neutral pHpH = 6.9996 = neutral pH

Polar – uneven (-)s between O & HPolar – uneven (-)s between O & H

Hydrogen bonds – weaker than covalent or ionicHydrogen bonds – weaker than covalent or ionic

Properties of Properties of WaterWater

Only natural substance found in all Only natural substance found in all three states of matter.three states of matter.Bonds easily with other substancesBonds easily with other substancesCapillary action allows water to be taken Capillary action allows water to be taken up by plant roots.up by plant roots.Cohesive molecule – produces surface Cohesive molecule – produces surface tension only surpassed by mercurytension only surpassed by mercuryAdhesive molecule – attraction btwn Adhesive molecule – attraction btwn different types of molecules (water & different types of molecules (water & glass)glass)Universal solvent – able to dissolve both Universal solvent – able to dissolve both ionic & other polar molecules.ionic & other polar molecules.