Biology 2051 Quiz 2.docx

# Biology 2051 Quiz 2.docx - Learning Outcomes Introduction...

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Learning Outcomes: Introduction to Biology (Chapter 3) 1. Define pH, and Calculate: pH is the Measure of the H + Concentration of a Solution o the addition of acids and bases to water can greatly change the H + and OH - concentrations over a very broad range o scientists use a log scale to describe the concentrations of these ions o pH - The mathematical expression of a solution’s hydrogen ion (H + ) concentration, defined as the negative logarithm to the base 10 of the H + concentration pH = -log 10 [H+] o Acidic – a solution that has a pH below 7 o Alkaline – a solution that has a pH above 7 A pH solution can affect o The shapes and functions of molecules o The rates of many chemical reactions

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o The ability of two molecules to bind to each other o The ability of ions or molecules to dissolve in water Due to the various effects of pH, many biological processes function best within a very narrow range of pH, and even small shifts can have a negative effect 2. pH of a solution given the concentration of protons [H+] or given the concentration of hydroxide ions [OH-]. 3. concentration of protons [H+] or the concentration of hydroxide ions [OH-] in a solution at a given pH. / 4. Describe the typical range of pH at which most life operates, such as the pH level for which proteins or structures in cells, might cease to operate or denature, or the pH of bodily fluids such as blood. The pH Scale is ranged from 0-14, however most life operates at 7.35 Ph, though this is dependent on where and what type of organism is being discussed. The pH is rarely below 7 and rarely above 8. To maintain a stable pH, buffers are used. A ph that is too low or too high can break down enzymes and functions. 5. Explain what power the scale of pH operates on? State what it means to jump from one number on the pH scale to another in terms of the concentration of H+ or -OH. Calculate how many times more acidic is pH=4 [H+]=0.0001, for example, than a substance of pH=6 [H+]=0.000001? Recognize relative concentrations of [H+] or [-OH] in both decimal form, or when written as a power of 10 [H+]=10 -4 . . 6. State the purpose of a buffer and describe what buffers do in biological systems, using an example. Predict what would happen in a solution if a buffer, an acid, or a base was added, with respect to pH and concentration of protons and hydroxide ions. Buffer – a compound that acts to minimize pH fluctuations in the fluids of living organisms Composed of a weak acid and its related base Example: carbonic acid (H 2 CO 3 ) Bicarbonate Ions (HCO 3 - ) 7. Describe the relationship between a weak base and H ions (protons)? Describe the relationship between protons and a weak acid? Explain how a buffer helps alleviate stomach acid discomfort, or how the carbonic acid system works in your blood.
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