Buffers

Question 1

What is the purpose of a buffer?

Answer 1

Allows a solution to exist without a wide change in pH; allows us to keep a tight control on pH so we can have biological processes occur

Question 2

What are buffers?

Answer 2

Buffers are solutions that contain a weak acid and its conjugate base or a weak base and its conjugate acid.

Question 3

What happens to a buffered solution when a strong acid or base are added in LIMITED quantity?

Answer 3

Buffers resist change in pH when strong acids or bases are added in limited quantity

Question 4

What is buffer capacity?

Answer 4

limit to the amount of acid/base that can be added before the buffer loses its ability to resist change.

Question 5

When adding acids to a solution, how will pH change while within the buffer capacity?

Answer 5

Minimal change.

Question 6

When adding acids to a solution, how will pH change while outside of the buffer capacity?

Answer 6

Significant change

Question 7

What does buffer capacity depend on?

Answer 7

of conjugate pairs in a solution

Question 8

How is blood pH controlled?

Answer 8

Blood pH is controlled through pH regulation which is a function of the buffer systems of the body in combination with the respiratory and renal systems.

Question 9

What are the three main buffer systems?

Answer 9

Three main buffer systems are the bicarbonate, phosphate, and protein buffer systems

Question 10

How does the respiratory system contribute to the buffer system?

Answer 10

The respiratory system directly impacts the carbonic acid buffer system through control of blood CO2 levels
(CO2 + H2O = Carbonic acid)

Question 11

What is the main acid we have in our bodies?

Answer 11

Carbonic acid

Question 12

How do the kidneys contribute to the buffer system in our bodies?

Answer 12

The renal system is regulated by various buffer systems and works to remove hydrogen ions through the kidneys.

Question 13

What is Le Chatelier’s principle?

Answer 13

When a system at equilibrium is disturbed, the system will adjust to reestablish that equilibrium

The change is usually the opposite of whatever occurred

Question 14

The charge of a drug compound is one factor that can dictate the movement of acid/base drugs across a cell membrane.

What controls charge?

Answer 14

Charge is controlled by both the pH of the solution and the pKa of the drug

Question 15

Drugs are usually what kind of acid/base?

Answer 15

Weak

Question 16

Does the pH of a drug change? What does this have an affect on?

Answer 16

Yes, depending on what area of the body we are in.

Affects solubility, distribution, and ability to cross the membrane

Question 17

What can the Henderson-Hasselbach Equation be used for?

Answer 17

Determining pH of a buffer solution

Determining pH of blood

Determining amounts of charged species at a particular pH

Question 18

Drug absorption via passive diffusion is directly related to what? What does this help us determine?

Answer 18

The ratio of ionized vs unionized drug.

Helps us determine if a drug can cross a particular cell membrane.

Question 19

What kind of drugs are better able to be absorbed in the stomach?

Answer 19

Acidic drugs

Question 20

The majority of local anesthetics are what kind of base? What does this imply?

Answer 20

Weak bases

Drugs with a pKa closes to our normal pH will be more in the lipid-soluble unionized form, thus allowing them to better cross the axonal membrane.