pH and buffers

Question 1

What is a buffer?

Answer 1

Mixtures of weak acids and their conjugate bases or weak bases and their conjugate acids

Question 2

On the midpoint of a pH graph what does this demonstrate?

Answer 2

[CH3COOH] = [CH3COO-]

pH=pKa

Question 3

How do buffers work?

Answer 3

Taking up any added protons and neutralising any added hydroxide

Question 4

What do buffer solutions inherent pH’s depend on?

Answer 4

Ratio of acid component to the conjugate base component and dissociation characteristics of the buffer.

Question 5

What is intracellular pH largely buffered by?

Answer 5

Phosphate and the histidine side chains of proteins

Question 6

What is extracellular pH buffered by?

Answer 6

Bicarbonate buffer system

Question 7

What are the three buffer systems in saliva?

Answer 7

Bicarbonate (most important in stimulated saliva)
Phosphate
Proteins

Question 8

What does carbonic anhydrase do?

Answer 8

Catalyses the uptake of proton to bicarbonate increasing the efficiency, retained in a pellicle

Question 9

What is plaque acid produced by?

Answer 9

Bacteria fermenting dietary carbohydrate