The Chemistry of Life

Parts of an Atom Nucleus Electrons (-) Protons (+) Neutrons (no charge) Electrons (-)

What is an element? A pure substance consisting only of one type of atom Which of the following are elements? Water The Helium in a balloon Steel Iron Oxygen Air Lithium Sodium NaCl

How many elements are in the human body?

Important elements for living organisms Carbon Oxygen Hydrogen Nitrogen Small amounts of: Phosphorus Sulfur

Bonding Each element has a certain number of bonds it prefers to make to be the most “stable” This number directly corresponds (in most cases) to the element’s position on the periodic table

These elements like to form…. 1 bond 4 bonds 2 bonds 3 bonds

Energy Levels - Every atom has energy “shells” around it. - Electrons constantly circulate the nucleus of an atom in these shells, or the electron cloud. - Each shell can only hold a certain number of electrons.

Carbon Carbon is critical for life on earth. All organic molecules contain carbon Carbon easily forms 4 bonds

Monomers and Polymers Polymerization – large compounds are built by joining smaller compounds together (like building with legos) Monomer – the small units used in polymerization (like 1 lego piece) Polymer – a molecular structure that consists of many smaller, repeating subunits (like a stack of legos)

Molecular Formulas NaCl H2O CaCO3 5H2O (NH4)2CO3 How many atoms in the following molecules? NaCl H2O CaCO3 5H2O (NH4)2CO3

Isomers Two or more molecules with the same molecular formula, but each have a different structure Example:

Isomers (cont.) Glucose Fructose

Why do I need to know all this? Macromolecules play a huge role in life on Earth. Knowing the different types of macromolecules, their functions, and properties, will give you a better all-around view of the chemistry of life. Macromolecule: “Giant Molecule” (Macro-great/large)

Types of macromolecules in Biology: -Carbohydrates -Lipids -Proteins -Nucleic Acids