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111 Biology Lab Practical :P Cell theory: all organisms are made of cells that store hereditary information in DNA. Gene theory: DNA sequences may be altered by mutation or by crossing over and segregation during meiosis. Theory of heredity: changes in DNA sequence produce individual, heritable variation. Theory of evolution: changes in DNA resulting in a more fit individual are passed down in greater numbers to the next generation, etc. genetic change over time. Scientific method: 1. observe a phenomenon and formulate questions 2. reflect on implications 3. propose a hypothesis 4. test the hypothesis 5. analyze the results 6. support, reject, or modify the hypothesis Difference between compound and dissecting microscopes: Dissecting use transmitted AND reflected light where as compound only uses transmitted. Dissecting is good for large, 3-d, opaque specimens. Dissecting has a lower magnification but a greater resolution compared to compound. Microscopes in general: as you move from higher to lower power, resolution increases but it is not linear. Properties of water: Neutral charge, negatively charged electrons, polar nature leads to weak bonds between water molecules, which causes water to remain liquid when other molecules of similar size are gases. Cohesion attraction between water molecules Adhesion when water molecules are attracted to other materials. Covalent bond forms when 2 atoms share two electrons within a molecule. Very strong, Hydrogen bond weak. Hydrogen with electronegative (F, O, N) Surface tension cohesion of water molecules in the absence of other attraction. pH potential hydrogen in solution. Represents concentration of hydrogen ions in water. The concentrations (H+) and (OH-) multiply to equal 1 x 10^-14^ Three ways to find pH: Anthocyanins class of compounds that occur naturally in plants. Appear read in acidic solutions, purple in neutral, and greenish yellow is strong basic solutions pH test papers pH accuracy meters and precision. Must calibrate using distilled water Molecular Transport across plasma membrane: Diffusion passive transport. Slow and inefficient over long distances. Down/along with concentration gradient. Membrane must be selectively permeable. Facilitated diffusion relies on transporter proteins to carry through tunnel channels. STILL PASSIVE Osmosis movement of water only. Active transport requires energy (ATP), against concentration gradient LUGOLS = turns blue/black in presence of starch, more specifically amylose polysaccharides Water potential Greater inside cell than outside, net movement out of cell. Greater outside cell than inside, net movement into cell. Equal is dynamic equilibrium, no net movement. Osmotic pressure pressure needed to stop the net movement of water. Turgor pressure positive pressure (makes plant cells TURGID) Osmotic potential opposite of Osmotic pressure. Potential of pure water = 0. Solutions have negative potentials (potential decrease as solution concentration increases). *cells in a hypertonic solutions shrink and shrivel. Four functional groups? carbonyl, hydroxyl, carboxyl, amino. Carbohydrates: Functions supply carbons for synthesis, fuel, energy storage, structure/support Saccharides (monosaccharides make up carbohydrates) Monosaccharides can be identified using BENEDICTS REAGENT which reacts with the double bonded oxygen on the aldehyde and ketone (carbonyl groups) Disaccharides linked by glycosidic bonds which are formed via dehydration synthesis (removal of water molecule/covalent bond). Hydrolysis breaks the glycosidic bonds. BENEDICTS only reacts to free reactive groups (unbounded) Polysaccharides chains of glucose linked molecules. Amylose = linear chain. Amylopectin branched chains. Starches are made up of both. A POSITIVE BENEDICTS TEST red/orange = strongest reducing sugars. Any color change usual indicates presence of reducing sugar. ... View Full Document

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