Chapter 1: A. Science is: 1. Investigating and understanding the natural world 2. Explaining events in the natural world 3. Using explanations to make predictions 4. Making observations, collecting data, inferring, hypothesizing processing, questioning, testing, evaluating, recommending . . . B. How Scientists Work Experiments on Generation of Life: 1. Redi tested his hypothesis testing one variable against a control group and discovered that maggots were not produced from rotting meat but from flies 2. Spallanzani proved Redi’s results and disproved Needham’s support of spontaneous generation Experiments (cont) 3. Pasteur improved on results further by using a curved-neck flask thus finally proving that living things come from living things C. Studying Life 1. Characteristics of Living Things a. b. c. d. e. f. g. h. Made up of cells Reproduce Universal genetic code Grow and develop Use materials and energy Respond to the environment Maintain a stable internal environment As a group, change over time 2. Branches of Biology a. molecular biology b. cellular biology c. histology, physiology, anatomy d. zoology, bacteriology, botany e. ecology, environmental science And more . . . D. Tools and Procedures 1. Common Measurement: Most scientists use a revised metric system known as: SI or International System of Units 2. Computers to collect and store data 3. Microscopes: Light and electron microscopes 4. Cell Cultures: reproduction of cells 5. Cell fractionation: separation of cell parts 6. Safety – see appendix B and wash hands after labs! Chapter 2: Chemistry of Life A. Matter 1. Atoms, electrons, protons, and neutrons 2. Elements/isotopes 3. Chemical compounds held together by ionic or covalent bonds B. Water 1. Polar compound 2. Because of polarity, hydrogen bonding occurs leading to adhesion and cohesion 3. Can be used to make mixtures such as solutions and suspensions 4. Neutral (7) on the pH scale a) Acids (below 7) have higher concentration of H+ ions b) Bases (7>14) have lower H+ concentration than water. C. Carbon Compounds 1. What’s special about carbon? a) Has 4 valence electrons and can bond with various elements b) Can bond with other carbons forming long chains and rings, more complex and larger molecules 2. Macromolecules: 4 groups of large polymers found in living things (organic molecules) a) Carbohydrates i. contain C, H, and O in a ratio of 1:2:1 ii. are major sources of energy iii. Examples are sugar,starch, monosaccharides and polysaccharides b) Lipids i. ii. Made of mostly C and H Store energy iii. Not soluble in water iv. Examples are fats, oils and waxes c) Nucleic Acids: RNA and DNA i. Units called nucleotides contain H, O, C, N and P ii. Store and transmit genetic information d) Proteins i. Polymers made of amino acids containing H, O, C, and N ii. Control rates of reaction, regulate cell processes, form bones and muscles, transport substances in and out of cells, fight disease IV. Chemical Reactions and Enzymes A. Chemical Reactions 1. New substances are formed through the breaking of bonds in reactants to form new bonds in products 2. Exothermic: give off energy and often occur spontaneously 3. Endothermic: require a source of energy 4. Examples: CO2 + H2O ↔C6H12O6 + O2 H2 + O2 →H2O B. Reaction Rates 1. Catalysts are chemicals that speed up a chemical reaction by lowering activation energy 2. Enzymes: proteins speed up chemical reactions occurring in cells 3. Enzymes provide a site for reactants (substrates) to come together