1. Homeostasis: The Effect of pH on Cells

2. Organisms need certain conditions to live Correct temperature Correct hydration (water) Correct amount of light Correct pH

3. pH pH means potential hydrogen pH measures of the H+ concentration of a solution. pH tells how strong an acid or base is

5. Living things need... A neutral pH (pH = 7) If acidic or basic they will die

6. How can living things maintain a neutral pH? Let’s look back at acids and bases

7. Acids ionic compounds (+ or - charge) that break apart in water and release hydrogen ion (H+) [positive ion] Stronger acids have MORE H+ (a higher concentration of H+) pH of an acid is from 0-6 on the pH scale Example: hydrochloric acid (HCl) (We will use this in the lab)

8. Bases ionic compounds that break apart in water to form a negatively charged hydroxide ion (OH-) pH of a base is from 8-14 on the pH scale Stronger bases have MORE OH- (a higher concentration of OH-) Example: Sodium hydroxide (NaOH) (We will use this in the lab today)

9. Back to Living Things/Cells... How do living things maintain their pH? (aka: maintain homeostasis) Buffers

10. Buffers maintain a concentration of H+ within the physiological range (blood/cells pH 7.35-7.45) Help control reaction rates in cells Help maintain the proper pH

11. The Liver Detoxifies blood (drugs and alcohol) Produces bile (digestion) Plays a major role in metabolism We will be using liver in the next lab (organ made of cells that contain buffers)