Biochemistry Pt. III - pH Scale

The pH Scale - runs from 0-14 and measures the percent of hydrogen ions in a substance via acidity

• Acidic pH - measures below 7.0; lower number = more acidic

• Neutral pH - measures at 7.0 (i.e. water)

• Basic pH - measures above 7.0; higher number = more alkaline

Buffers - maintain homeostasis by minimizing changes in pH

• Human Body’s Normal pH - 7.4; increases/decreases from this number will dismantle enzymes, weaken nerve and muscle activity, and collapse metabolic activity

• Hemoglobin - one of the most important buffering agents; acts as a buffer by taking on or releasing an extra proton

• Carbonic Acid (H₂CO₃) and Bicarbonate Ion (HCO₃-) - buffer in the bloodstream that responds to changes in pH in the blood:

  • CO₂ + H₂O ↔ H₂CO₃ ↔ H+ + HCO₃-

  • neutral base weak acid weak base

Acid Precipitation - acidic rain, snow, or fog that has a pH less than 5.6; mostly produced by burning fossil fuels (and the release of CO₂)