D.2 - Aspirin And Penicillin

Question 1

What does aspirin do and how does it function?

Answer 1

It is a mild analgesic by intercepting the pain stimulus at the source, often by interfering with the production of substances that caused pain, swelling or fever.

Question 2

What is aspirin prepared from?

Answer 2

Salicylic acid.

Question 3

What can aspirin be used for?

Answer 3

It can be used as an anticoagulant (prolonging blood clots from forming), in prevention of the recurrence of heart attacks and strokes and as a prophylactic (intended to prevent disease).

Question 4

What is penicillin?

Answer 4

Penicillins are antibiotics produced by fungi?

Question 5

What is the core structure of penicillins?

Answer 5

A beta-lactan ring.

Question 6

How do some antibiotics work?

Answer 6

Preventing cross-linking of the bacterial cell walls.

Question 7

What will happen if the side-chain in penicillins are modified?

Answer 7

They become more resistant to the penicillinase enzyme.

Question 8

How is aspirin produced?

Answer 8

By reacting salicylic acid with ethanol anhydride. Salicylic acid is converted to aspirin through esterification (condensation reaction).

Question 9

What is solubility of aspiring?

Answer 9

Very low solubility in cold water - this process removes the soluble acids but not the aspirin.

Question 10

How is aspirin purified?

Answer 10

Through a process known as recrystallisation; this involves dissolving the impure crystals in a small volumen of hot ethanol. The water is then added and the solution is cooled slowly and then chilled. The acetylsalicylic acid will recrystallise, and the unreacted salicylic acid remains dissolved in the solution.

Question 11

How can the purity of aspirin be determined?

Answer 11

By its melting point and by using the infrared spectrum.

Question 12

What happens if impurities are lower than the melting point?

Answer 12

It causes it to melt over a wider temperature range.

Question 13

What is mild analgesic?

Answer 13

It is a painkiller which blocks the sensation of pain at the source. It blocks the action of the enzymes that produce prostaglandins.

Question 14

What are prostaglandins?

Answer 14

They are involved in the transmission of pain impulses to the brain, as well as causing fever and swelling.

Question 15

What does aspirin prevent?

Answer 15

Prevents prostaglandins from being synthesised, there y reducing or eliminating the pain.

Question 16

What is aspirin taken for?

Answer 16

For its anti-inflammatory properties such as arthritis and rheumatism (pain in joints).

Question 17

What is the most common side effect of aspirin?

Answer 17

It can cause bleeding of the lining of the stomach.

Question 18

What increases the side effect of aspirin?

Answer 18

By drinking alcohol (ethanol) at the same time as taking aspirin (this is known as the synergistic effect).

Question 19

What is the synergistic effect?

Answer 19

When two drugs increase each other’s effectiveness when taken together.

Question 20

What is the importance of the beta-lactam ring on the action of penicillin?

Answer 20

It interferes with the cell wall formation in bacteria by inhibiting the enzymes responsible for creating cross-links in the cell wall.

Question 21

What happens when the beta-lactan rings comes into contact with bacteria?

Answer 21

The ring opens and binds irreversibly to the enzyme responsible for catalysing cross-linking in the cell wall of the bacteria.

Question 22

What happens when water enters the cell?

Answer 22

This increases the osmotic pressure inside the cell, causing it to burst.

Question 23

What is antibiotic resistance?

Answer 23

It is the ability of bacteria to resist the effects of an antibiotic.

Question 24

How is bacterial resistance built up against antibiotics?

Answer 24

From the misuse or overuse of antibiotics.
E.g. over-prescription of penicillin for minor illnesses and the failure of patients to complete the course of antibiotics as prescribed by the doctor.

Question 25

What happens when the side-chain of penicillin is modified?

Answer 25

It results with penicillins becomes more resistant to the penicillinase enzyme - the penicillinase enzyme could deactivate the original form of penicillin, penicillin G.