Ph bio111
- 1. Bio 111 2009 Dra . María I. Lázaro
- 2. Table 2-2 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc.
- 3. Figure 2-6b Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc. 8p+ 8n (b) Polar covalent bonding (oxygen: slightly negative) (–)Water (H2O or H—O—H) (hydrogens: slightly positive) (+) (+) Electrons spend more time near larger nucleus. smaller positive charge larger positive charge
- 4. Figure 2-14 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc. hydrogen ion (H+ ) hydroxide ion (OH– ) water (H2O) (+)(–)
- 6. Figure 2-15 Biology: Life on Earth 8/e ©2008 Pearson Prentice Hall, Inc. H+ concentration in moles/liter increasingly acidic increasingly basic neutral (H+ = OH– ) (H+ > OH– ) (H+ < OH– ) 100 10–1 10–2 10–3 10–4 10–5 10–6 10–7 10–8 10–9 10–10 10–11 10–12 10–13 10–14 1molarsodium hydroxide(NaOH) 1molarhydrochloric acid(HCI) 10 2 3 4 65 7 8 9 stomachacid(2) lemonjuice(2.3) "acidrain"(2.5–5.5) tomatoes beer(4.1) vinegar,cola(3.0) orange(3.5) blackcoffee(5.0) normalrain(5.6) waterfromfaucet urine(5.7) milk(6.4) purewater(7.0) seawater(7.8–8.3) saliva blood,sweat(7.4) bakingsoda(8.4) toothpaste(9.9) householdammonia(11.9) washingsoda(12) ovencleaner(13.0) chlorinebleach(12.6) phosphatedetergents draincleaner(14.0) 1110 12 13 14 pH value
Editor's Notes
- Table 2-2 Common Types of Bonds in Biological Molecules
- FIGURE 2-6b Covalent bonds involve shared electrons (b) Oxygen lacks two electrons to fill its outer shell, so oxygen can form polar covalent bonds with two hydrogen atoms, creating water. Oxygen exerts a greater pull on the electrons than does hydrogen, so the &quot;oxygen end&quot; of the molecule has a slight negative charge (-) and the &quot;hydrogen end&quot; has a slight positive charge (+).
- FIGURE 2-14 Some water is ionized
- FIGURE 2-15 The pH scale The pH scale reflects the concentration of hydrogen ions in a solution. The pH (upper scale) is the negative log of the H+ concentration (lower scale). Each unit on the scale represents a tenfold change. Lemon juice, for example, is about 10 times more acidic than orange juice, and the most severe acid rains in the northeastern United States are almost 1000 times more acidic than normal rainfall. Except for the inside of your stomach, nearly all the fluids in your body are finely adjusted to a pH of about 7.4.