Chapter 6 Chemistry of Life

Elements Approximately 115 are known to exist Only 25 are essential for living things 4 elements make up 96% of the human body: Carbon Hydrogen Oxygen Nitrogen

Atoms Smallest particle of an element that has the element’s characteristics Basic building block of matter Has a nucleus with protons (+) and neutrons (no charge) and an electron cloud (-).

Atomic number tells you number of protons and electrons Atomic mass is determined by the number of protons and neutrons added together

Determining Number of Protons, Electrons, & Neutrons

Isotopes Atoms of the same element that have different numbers of neutrons Example: C-14, C-12, C-13 Used to date fossils, diagnose or treat disease

Compounds Substance composed of two or more elements in definite proportions Examples: NaCl, H2O Created through bonding

Ionic Bonding When electrons are transferred from one atom to another in order to achieve stability. Creates one atom that has a positive charge and one that has a negative charge The opposite charges cause the atoms to be attracted to each other.

Covalent Bonding Atoms share pairs of electrons in order to reach stable outer energy levels. The shared pair(s) keep the molecule together

Chemical Reactions Occur when bonds are formed or broken Reactants  Products 2H2 + O2  2H2O

Acids & Bases pH – measure of how acidic or basic something is Scale ranges from 1(acid)-14(base) 7 is neutral

Organic Biomolecules Why is carbon so important? What makes it so great? Carbon can make 4 bonds , it has 4 electrons to share (covalent bonds) This allows it to make many different kinds of compounds Carbohydrates, lipids, proteins, nucleic acids – these are all organic polymers made with carbon

Carbohydrates Made of carbon, hydrogen, and oxygen Ratio will be 2H:1O C6H12O6

Carbohydrates Continued Monosaccharide – single, simple sugars Glucose and fructose Disaccharide – double sugar Lactose and sucrose Polysaccharide – large sugar Starch and glycogen Important for immediate energy and making cell parts

Carbohydrate Isomers Compounds that contain the same number and kinds of atoms, just arranged differently. Glucose and fructose

Lipids Made of carbon, hydrogen, and oxygen Ratio of H:O is much greater than 2:1 Main components are fatty acids and glycerol

Lipids Continued Important for: Fats, waxes, and oils Cell membranes Energy storage (long-term energy) Insulation Fats, waxes, and oils

Saturated vs. Unsaturated fats All carbons are connected with single bonds Some of the carbon atoms are connected with double and/or triple bonds because hydrogen has been removed.

Proteins Made of carbon, hydrogen, oxygen, and NITROGEN

Proteins Continued Made from subunits called amino acids Important for: Tissue structure Muscle contracting Transporting oxygen Immunity Enzymes

Nucleic Acids Biomolecule that stores cellular information in a code Made of subunits called nucleotides Contain carbon, hydrogen, nitrogen, oxygen, and phosphorus Examples: Deoxyribonucleic Acid and Ribonucleic Acid