paper 3 option D

Question 1

how does the beta lactam ring work against bacteria?

Answer 1

it inhibits the enzyme transpeptidase in the bacteria that produces the cell wall. the bacteria (cells of bacteria) therfore absorbs water and bursts.

Question 2

what are the bond angles in the beta lactam ring? and what would they be in an open structure?

Answer 2

90 degrees

120 degrees and 109.5 degrees.

Question 3

how can pennicilin be modified to be effective against bacteria?

Answer 3

modify side chain

Question 4

why does pennicilin not work on human cells?

Answer 4

human cells do not have cell walls.

Question 5

why is diamorphine more effective in crossing the blood brain barrier than morphine or codeine?

Answer 5

doesnt contain hydogen bonds (hydroxyl group) so is less polar than the other two, and the blood brain barrier is non polar.

Question 6

in a buffer question you are given the Ka to work with, what must you do before using the formula?

Answer 6

convert Ka into pKa by doing log– of the Ka.

Question 7

outline two ways in which viral medication works agaisnt viruses?

examples of viral medicine?

Answer 7

prevents release of replicated viruses from host cell
by inhibiting viral enzymes/neuraminidases «needed to release virus»

blocks enzyme activity in host cell so that the virus cannot use it to multiply.

oseltamivir and zanamivir

Question 8

suggest two reasons why chlorinated solvents should neiter be released into the atmosphere or burnd?

Answer 8

cause cancer and produce dioxins

Question 9

explain the low and high environmental impacts of medical nuclear waste? give examples

Answer 9

low level nuclear waste:
emmits weak level of ionization energy and has a short life. ex: gloves/syringes

high level nuclear waste:
the reverse of everything. ex. nuclear fuel + rods.

Question 10

how does aspirin work? what type of an analgesic is it?

where does it come from

Answer 10

mild analgesic

interferes with the production of prostaglandins at the site of injury/source of pain .

willow bark

Question 11

what are opiates? examples

Answer 11

strong analgesics

morphine, diamorphine and codeine

Question 12

Outline how codeine
can be synthesized from morphine

and another than is used to prepare diamorphine from morphine

Answer 12

react with methly iodide CH3I in alkaline solution

with ethanoic anyhydride

Question 13

Explain why opiates are addictive

Answer 13

interact with opioid receptors in the brain

prevents transmission of pain impulses inside the brain

gives a feeling of pleasure/euphoria «that the person craves»

Question 14

Outline the difference between the therapeutic index in animal studies and the
therapeutic index in humans

Answer 14

n animal studies lethal dose/LD50 AND in humans toxic dose/TD50

Question 15

State the method of drug administration that gives the maximum bioavailability

Answer 15

intravenous so in blood stream

Question 16

Explain how ranitidine (Zantac) reduces stomach acid production

Answer 16

prevents histamine binding to H2/histamine receptors «and triggering acid
secretion»

prevents parietal cells from releasing/producing acid

Question 17

in the formula for the buffer solution, is the acid on top or at the bottom?

Answer 17

it is base/salt over the acid.

acid on the bottom

Question 18

structurally why is the beta lactam ring good against bacteria?

Outline what is meant by the term “ring strain”.

Answer 18

/amine group «in ring» is «highly» reactive ✔

angles of 90° instead of 109.5/109/120° angles

ring strain refers to the instability resulting from abnormal bond angles

Question 19

how do nexion and prilosec reduce the stomach acidity?

Answer 19

inhibit the proton pumps in the stomach directly which prevents the secretion of H+ into the stomach.

Question 20

what must oseltavimir undergo in the body?

Answer 20

its ester group must be changed into a carboxylic group

Question 21

from what is oseltamivri synthesized?

suggest an e alternative green chemistry source of shikimic acid

Answer 21

shikimic acid from star anise (plant)

genetically engineered bacteria/E.coli

Question 22

why is cold water used to isolate aspirini from impurities?

Answer 22

aspirin/product has low solubility «in water» at low temperatures 

Question 23

compare the bioavaliabity of soluble aspirin and aspirin

Answer 23

«marginally» higher AND increase absorption in mouth/stomach «mucosa»

Question 24

how can aspirin be converted into soluble aspirin

Answer 24

react with NaOH

Question 25

state two techniques that can be used to to confirm aspirin’s identitiy

Answer 25

melting point and mass spectrometry