The Chemistry of Life

2-1: The Nature of Matter Atoms (Basic unit of matter) Subatomic particles that make up atoms are protons, neutrons, and electrons

Subatomic particles Protons - Neutrons - Electrons - Positively charged (+) Not charged (neutral) Negatively charged (-) Bind together to form the nucleus Electrons Protons Neutrons Nucleus

Element - a pure substance that consists of just one type of atom Isotope - atoms of the same element that differ in the number of neutrons they contain Nonradioactive carbon-12Nonradioactive carbon-13Radioactive carbon-14 6 electrons 6 protons 6 neutrons 6 electrons 6 protons 8 neutrons 6 electrons 6 protons 7 neutrons Elements and Isotopes

Radioactive isotopes Can be dangerous Can be used practically Radioactive dating Treat cancer Kill bacteria

Chemical Compounds / Bonds Compound - A substance formed by the chemical combination of two or more elements in definite proportions Ex) H2O, NaCl Ionic Bonds - Formed when one or more electrons are transferred from one atom to another

Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na + ) Chloride ion (Cl - ) Transfer of electron Protons +11 Electrons -11 Charge 0 Protons +17 Electrons -17 Charge 0 Protons +11 Electrons -10 Charge +1 Protons +17 Electrons -18 Charge -1 If an atom loses an electron it becomes positive ( Na + ) If an atom gains an electron it becomes negative ( Cl - ) } Ions

Covalent Bonds - Forms when electrons are shared between atoms Much of our planet is covered in water Water is necessary for life to exist If life exists on other planets, there most likely is water present Water has many properties that make life possible

Polarity (-) (+) The oxygen atom has a stronger attraction for electrons (+)

Hydrogen Bonds Because of waters partial charges, they can attract each other and create hydrogen bonds Not as strong as covalent or ionic bonds Waters ability to create multiple hydrogen bonds gives it many special properties

Cohesion - Attraction between molecules of the same substance Adhesion – Attraction between molecules of different substances

Solutions and Suspensions Mixture - Material composed of two or more elements or compounds that are physically mixed but not chemically combined Solutions - Mixture of two or more substances in which the molecules are evenly distributed Suspension - Mixture of water and non-dissolved materials (separate into pieces so small, they never settle out)

The pH scale Indicates the concentration of hydrogen ions in a solution Acid - Any compound that forms H + (hydrogen) ions in solution Base - A compound that produces OH - (hydroxide) ions in solution

Neutral Acid Base

What makes carbon special? Carbon has 4 valence electrons and can bond with various elements Can bond with other carbons forming long chains and rings more complex and larger molecules MethaneAcetyleneButadieneBenzeneIsooctane

Macromolecules “giant molecules” Smaller units called monomers join together to form the larger macromolecules called polymers. There are 4 groups of macromolecules Carbohydrates Lipids Nucleic Acids Proteins

Carbohydrates Contain carbon (C ), hydrogen (H), and oxygen (O) atoms in a ratio of 1:2:1 [ C 6 H 12 O 6 ] Are a major source of energy Examples include sugar, starch, monosaccharides and polysaccharides Starch Glucose

Lipids Made mostly from C and H Used to store energy Not soluble in water Examples include fats, oils, and waxes

Lipid Glycerol Fatty Acids

Nucleic Acids Macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus Double Helix

Nucleotides Consists of 3 parts: 5-carbon sugar, phosphate group and nitrogen base Nitrogen Base 5-Carbon Sugar Phosphate group

2 kinds of nucleic acids RNA (ribonucleic acids) – contains sugar ribose DNA (deoxyribonucleic acid) – contains sugar deoxyribose

Proteins Polymers made of amino acids containing H, O, C, and N Control rates of reaction, regulate cell processes, form bones and muscles, transport substances in and out of cells, fight disease

Amino Acids General structureAlanineSerine Carboxyl group

More than 20 different amino acids, can join to any other amino acid The instructions for arranging amino acids into many different proteins are stored in DNA Each protein has a specific role The shape of proteins can be very important

Proteins Amino Acids

Chemical Reactions - A process that changes or transforms one set of chemicals into another Reactants - Elements or compounds that enter into a reaction Products - Elements or compounds produced by a chemical reaction

Example Reaction: Getting rid of carbon dioxide In the blood In the lungs CO2 + H20  H2CO3 (carbonic acid) H2CO3  CO2 + H2O Released as you breathe

Energy in reactions Energy-Absorbing Reaction Energy-Releasing Reaction Products Activation energy Activation energy Reactants

Activation Energy The energy that is needed to get a reaction started

Catalysts – are chemicals that speed up a chemical reaction by lowering activation energy Enzymes: Biological catalysts (proteins) Speed up reactions in cells Very specific Named for the reaction is catylzes Enzyme names always end in -ase Substrates: The reactants of enzyme catalyzed reactions The active site of the enzyme and the substrate have complementary shapes Fit like a lock and key

Enzyme Action Enzyme – substrate complex