FORM & FUNCTION (Acid and Base)

Question 1

pH

Answer 1

-power of hydrogen
-measurement of how acidic or basic a solution is
Ex. blood=7.4
-low pH=acidic, more H ions
-higher pH=basic, less H ions

Question 2

why is pH important?

Answer 2

-enzymes function optimally over a narrow range of pH
-too basic or acidic ->protein denaturation
-altered activity -> change in metabolic regulation and cell viability -> cell death
*digestive enzymes (pepsin) are optimal at low pH
*indicator of the relative amount of CO2 in the body

Question 3

why does pH fluctuate?

Answer 3

-CO2 is a by product of cellular metabolism
-CO2 in the blood reacts with water in the presence of carbonic anhydrase makes carbonic acid
-carbonic acid can then dissociate into H ions and bicarbonate (*contributes to acidification of they system)

Question 4

Weak vs. strong acid

Answer 4

-weak: partial dissociation (ex. carbonic acid)
-strong: complete dissociation (ex. hydrocholric acid)

Question 5

equilibrium constant (Ka)

Answer 5

-what maintains the ratio
-numerical representation of the acids strength in a solution
-low Ka=weak acid

Question 6

pKa

Answer 6

• (-log) of Ka
  -constant that determines which side the equilibrium shifts in a given environment (weak vs. strong acid)
  -pKa high=weak acid

Question 7

pKa of carbonic acid (blood)

Answer 7

=6.1
-carbonic acid is in equilibrium with CO2 and H2O

Question 8

if pH<pKa

Answer 8

-[HA] > [A-]
*more protonated form

Question 9

if pH = pKa

Answer 9

• [HA] = [A-]
  *equal amount

Question 10

if pH > pKa

Answer 10

-[HA] < [A-]
*more deprotonated form

Question 11

blood pH equation

Answer 11

=6.1 + log10 ([bicarbonate]/ (0.03xP CO2))

Question 12

blood gas test

Answer 12

-routine test to determine acid-base and oxygen status

Question 13

factors that influence blood pH

Answer 13

1. Respiratory (rate of breathing)
2. Metabolic origins (activites of cells and renal regulation)