Chemistry of Life

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

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

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

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

Organic Compounds Compounds that contain carbon Compounds that contain carbonTypes: 1. Carbohydrates 1. Carbohydrates 2. Lipids 2. Lipids 3. Proteins 3. Proteins 4. nucleic acids 4. nucleic acids

Inorganic Compounds Compounds that generally do not contain carbon atoms Compounds that generally do not contain carbon atoms Examples Examples Salt, water, rust Salt, water, rust * Some inorganic compounds also contain carbon; for example carbon monoixde, carbon dioxide, and some minerals.

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

Molecule Building Monomers: small building blocks molecules “ one- part” “ one- part” Monomers covalently link to make larger molecules

Polymers: molecules formed by linking two or more monomers “ many parts” “ many parts” Polymers made of thousands of monomers are macromolecules

Making and Breaking Polymers Organisms use chemical reactions to make and break covalent bonds of macromolecules

Carbohydrates Composed: Carbons, Hydrogen, Oxygen Oxygen Molecules are in a 1:2:1 ratio * For every carbon there is 2 hydrogens and one oxygen * For every carbon there is 2 hydrogens and one oxygen Monomer: monosaccharides Polymer: Polysaccharides

Carbohydrate Uses most organisms use carbohydrates as an energy source most organisms use carbohydrates as an energy source For example: Plants make woody materials for support. Insects have a hard outer covering called chitin.

Lipids Nonpolar molecules that are not soluble in water Composed of Carbon, Hydrogen

Types of Lipids Fats Fats Phospholipids Phospholipids Waxes Waxes Steroids Steroids

Proteins

Proteins Amino Acids Proteins are composed of Carbon, Hydrogen, Oxygen, and Nitrogen 20 different amino acids combine in different 3 dimensional shapes to make a LARGE variety of different proteins with a HUGE variety of different functions

Nucleic Acids

Hereditary information Essential to life Monomer: Nucleotide Polymers: DNA and RNA

Water Essential part of living things - live only 6 days without it - live only 6 days without it Live for 2 weeks without food. 70% of body made of water

Polarity of Water Molecules Oxygen's 8 (+)s vs. hydrogen's 2 means oxygen has a stronger attraction for electrons. The molecule has a bent shape as a result and the oxygen end has a slight (-) charge so hydrogen end has a …..

Properties of Water What we know. Turns to a solid at 0°C Vapor at 100°C. Density = 1 gram per cubic centimeter (1 g/cm 3 ) Neutral - 10 protons, 10 electrons total pH = = neutral pH Polar – uneven (-)s between O & H Hydrogen bonds – weaker than covalent or ionic

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