Atoms Atom smallest part of an element that has the characteristics of that element. Each element has a distinct atom based on structure.

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1 Atoms Atom smallest part of an element that has the characteristics of that element. Each element has a distinct atom based on structure. Nucleus- positively charged contains protons (p+), neutrons(n0), Outside the nucleus- electrons (e-). P# determines the element Atoms contain = # s of protons and electrons creating a net charge of 0.

2 Isotopes of an element Atoms that have same # of protons but different # s of neutrons. Ex. Carbon contains usually 6 neutrons but isotope can have 7 or 8 neutrons. C- 12, C-14 Isotopes used in medicine and science unstable and give off radiation.

3 Compounds and Bonding Compounds are substances that are composed of differently elements chemically bonded. (Water, Salt) Covalent Bonds when two elements share electrons H 2 0 Ion an atom that gains or looses electrons and has an electrical charge.

4 Ionic Bond attractive force between 2 ions of an opposite charge. Ex. Na + Cl Sodium becomes stable by loosing an electron and Chlorine becomes stable by gaining an electron. Not common in nature but are needed in biological processes. Elements properties change when created into a compound.

5 Covalent bonds Ionic Bonds

6 Mixtures and Solutions Mixture is a combination of substances that retain their own properties. Solution a mixture which one or more substances are distributed evenly into another. Solute dissolved into solvent Salt (solute)dissolved into water (solvent)

7 Water and Its Importance Water is made up of covalent bonds of Oxygen and hydrogen. Water is an example of a polar molecule. A molecule w/an unequal distribution of charge Water has a positive and negative end on the molecule.

8 Water Continued Since water is polar it has the ability to dissolve many ionic compounds, such as salt. It also dissolves other polar molecules, such as sugar. Water has the ability of Cohesion. Attraction between molecules of the same substance. Hydrogen bonds are important b/c they hold large molecules such as proteins.

9 Acids and Bases Measured using ph scale ranges from Neutral; <7 Acid; >7 Base Acid is any substance that forms hydrogen ions(h+) in water. Ex. Hydrochloric acids. Bases are any substances that forms hydroxide ions (OH-)in water Ex Ammonia NaOH ph above 7 Buffers are used to help decrease dramatic change in an acid or base.

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11 Carbon Compounds Role of Carbon in Organisms Possibility of forming 4 covalent bonds. Carbon can bond with other C atoms and elements. Form Rings, Straight Chains or Branched Chains Isomers -compounds that have same formula but different 3-D structures. Ex. Glucose and Fructose both have C 6 H 12 O 6 formula.

12 Multiple chains C compounds vary in size from 1-2 C atoms to 1000s of C atoms. Large molecules called macromolecules or biomolecules Built binding small molecules (monomers) together to form chains called polymers. Ex. Proteins

13 C Compound #1: Carbohydrates Used by cells to store and release energy, organic compound composed of C, H, O Simple sugar called monosaccharide Ex. Fructose and Glucose 2 monosaccharides bonded together are called Disaccharide- glucose & fructose combine form sucrose.

14 C Compound #1: Carbohydrates. Polysacchrides largest carbohydrate, polymer of many monosaccharide units Ex. Starch, cellulose, glycogen. Starch highly branched chains of glucose. Glycogen is the storage form in animals more branched than starch. Cellulose forms walls of plants like chain link fence

15 C Compound #2: Lipids Organic compounds that have a large portion of C-H bonds- less oxygen. Commonly known as Fats and oils Don t dissolve in water b/c molecules are non polar (that s why grease floats on water when washing dishes). Used for energy storage in plants, and major component of membranes. Most types consist of 3 fatty acids

16 C Compound #3: Nucleic Acids Store and transmit hereditary, or genetic information. A macromolecule. Subunits called nucleotides a base, a sugar, and phosphate group. DNA (Deoxyribonucleic acid) master copy of organisms info code. RNA- (Ribonucleic Acid) forms a copy if DNA for use in protein synthesis.

17 C Compound #4: Proteins. Build structure& carry out cell metabolism, large complex polymer composed of C, H, O, N, and S. Building blocks of proteins are Amino Acids 20 common acids. Vary in structure differently from other biological molecules. Covalent bond formed between Amino acids are called peptide bonds. Happens with the removal of H and OH group. Order of Amino Acids determines the kinds of proteins

18 Amino Acids All have a Carboxyl group (COOH), A hydrogen Atom (H), an Amino Group (NH 2 ) and a variable group that changes with each acid. Peptide Bond H20 removed

19 Chemical Reactions Process that changes one set of chemical into another. Involve Reactants to produce products. Always involve the breaking of bonds and the formation of new bonds. Some chemical reactions release energy, most of the time spontaneously. When reactions absorbs energy another source of energy is used.

20 Enzymes Enzymes are biological catalysts. A Catalyst is a substance that speeds up the rate of a chemical reaction. Enzymes speed up reactions that take place in cells. Lower the energy needed to start the reaction.