Study Guide for Exam 1 Dr. Osborne I. Introduction A. Scientific Method I. An observation is made 2. A hypothesis is constructed to explain the observation 3. An experiment is conducted to test the hypothesis 4. The hypothesis is either supported or disproved B. The Metric System 1. Units of measure exist for length, volume, mass and time 2. Prefixes are used to indicate multiples of 10 C. Scientific Notation I. A special system is used to write numbers less than I'or greater than lOin a uniform way 2. The number is made to fit between 1 and 10 and is multiplied by 10 raised to the correct power n. Simple Chemistry A. Atoms l. Fundamental particles a. Proton i. The proton has a change of + I and a mass of I AMU ii. The proton is found in the nucleus . iii. The number of protons is called the atomic number of the atom b. Neutron i. The neutron is neutral with no charge arid has a mass of 1 AMU ii. The neutron isJound in the nucleus along with the proton iii. The number of protons and neutrons is the atomic mass of the atom c. Electron i. The electron has a charge of-1 and is weighs 5.5 x 10.4 AMU ii. Electrons are found in shells surrounding the nucleus ofthe atom 2. Atomic structure a. Protons and neutrons are found in the nucleus. electrons orbit the nucleus in shells b. The first shell holds two electrons, the second and third shells hold eight electrons each". c. The outer electrons are the only ones involved in chemical bonding 3. Elements a. An element is composed ofonly one type of atom b. There are over 108 different elements c. The elements can be arranged in a periodic table according to their properties 4. Molecules a. Electrically neutral structures ofatoms b. May have same or different atoms 5. Compounds a. _Composed ofa singIe kind ofmolecule b. Molecules of compounds can be broken down into their component atoms B. Chemical Bonding l. Ionic bonds a. Formed by complete transfer of one or more electrons b. Involves only the electrons in the outer shell c. Atom losing electron(s) becomes a positive ion d. Atom gaining electron(s) becomes a negative ion e. Final result is that each ion has a complete outer shell 2. Covalent bonds a. Formed by sharing electrons between atoms b. Involves only the electrons in the outer shell c: Final result is that each atom has a complete outer shell including the shared electrons2 C. The pH Scale I. Ionization a. Ions are formed by loss or gain of electrons b. Ionic compounds dissolved in water will separate into their component ions c. Water can ionize to produce hydrogen ions (H+) and hydroxide ions (OW) 2. Neutralization a. Acids form hydrogen ions b. Bases form hydroxide ions c. Acids and bases react with and neutralize each other 3. The pH Scale a. The pH scale measures the strength of an acid or a base b. Pure water is pH 7 which is the neutral point c. The pH scale is logarithmic d. Acids i. Acids have pH less than 7 ii. The smaller the number the stronger the acid is e. Bases i. Bases have pH greater than 7 ii. The higher the number the stronger the base is D. Organic Chemistry I. General considerations a. Organic chemicals contain carbon b. Many important biological chemicals are organic c. Biological molecules are polymers are made of repeating subunits d. Condensation reactions are used to synthesize biological molecules e. Synthesis is part ofthe Hydrolysis-Synthesis Cycle of molecules 2. Carbohydrates a. Carbohydrates have a ratio ofH:O of2:1 b. Monosaccharides (simple sugars) are the building blocks ofcar~ohydrates c. Disaccharides are formed by condensation reaction between two monosaccharides d. Polysaccharides are formed by condensation reaction of many identical monosaccharides 3. Lipids a. Lipids have much more hydrogen than oxygen b. Fats and oils are triglycerides made of glycerol and three fatty acids c. Waxes are made by condensation reactions oflong-chain fatty acids and long-chain alcohols d. Phospholipids contain glycerol, two fatty acid tails and a polar head e. Steroids have a complicated structure of interlocking rings 4. Proteins a. Proteins are made of amino aCids i. Amino acids have carbon with an amino group, a carboxyl group, hydrogen and a side chain ii. -There are about-20 different side chains therefore about 20 differentaminoacids---- -----b.- Synthesis of proteins involves condensation reactions between the component amino acids c. Amino acids of proteins are joined by peptide bonds d. Structural proteins connect body structures or are components of body structures e. Enzymes are proteins which permit biological reactions to occur at body temperatures 5. Nucleic acids a. Nucleic acids are polymers composed ofnucleotides b. Each nucleotide contains a base, a phosphate and a sugar c. Deoxyribonucleic Acid (DNA) i. DNA is found in the chromosomes in the nucleus of the cell ii. DNA directs all cellular activities and makes up the genes of the organism d. Ribonucleic Acid (RNA) comes in three forms and is involved in protein synthesis3 III. Biology ofCells A. The cell theory I. All living things are made of cells 2. All cells arise from pre-existing cells 3. There are exceptions to the cell theory a. Mitochondria and chloroplasts are self-replicating b. Viruses are not true cells B. Microscopes 1. Simple microscopes contain only one lens 2. Compound microscopes have two lenses working in series 3. Electron microscopes use a beam ofelectrons to illuminate the specimen instead of using light 4. Ultrastructure is the fine details of a cell seen in the electron microscope but not in the light microscope C. Cell Structures I. Cell membrane . a. The cell membrane is made of phospholipid and proteins b. The appearance ofthe cell membrane is called a fluid mosaic c. The cell membrane is found in all cells, both prokaryotic and eukaryotic 2. Nucleus a. The nucleus is found in all eukaryotic cells b. The nucleus is sl:1rrounded by a nuclear membrane i. The nuclear membrane separates the nucleus from the cytoplasm ii. The nuclear membrane has pores and channels which connect to the endoplas"mic reticulum c. Chromosomes are found in the nucleus " i. Chromosomes are made of DNA and proteins ii. Chromosomes carry the genes which are the hereditary information of the cell d. The nucleolus is a structure involved in the formation of ribosomes 3. Cellular structures common to all eukaryotic cells a. The cytoplasm is found inside the cell but outside the nucleus b.