Biology 1 Exam 1 Study Guide

What are the four biological macromolecules and which

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Unformatted text preview: o water density, maximum density at 4 ˚C, and freezing? Why does frozen water float based on H- bonds? How does the high specific heat of water and ocean currents contribute to “buffer” extremes of temperature from the tropics to the poles on Earth? Know that a solution is a solute dissolved in a solvent, and that when the solvent is water it is an aqueous solution. Why is water an excellent solvent of polar and ionic molecules; what is a hydration shell? What is the difference between hydrophilic and hydrophobic and how does that relate to the polarity of bonds (know examples discussed, protein versus fat)? Solutes and solvents both move by diffusion in the direction of high to low concentration (i.e., movement follows the concentration gradient); their respective movements are opposite to one another. When solute concentration is high, solvent concentration is effectively lowered compared to where the solute concentration is low. Water molecules can dissociate (split) to a proton (H+) and hydroxyl anion (OH- ). The relative amounts of these ions influence the acidity or basic nature of the solution, which is expressed as pH (= - log[H+]). The more acidic the lower pH; the more basic (alkaline) the high pH; the range of pH is 0 – 14. Each unit of pH is a ten- fold difference in proton concentration; therefore a two unit difference is a hundred- fold, etc… Neutral aqueous solutions are pH = 7, and most life prefers conditions of pH 6- 8. What are the four biolo...
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