Chemistry 12 (HL)
Unit 6 / IB Topic D7
Medicines and Drugs - Part 7
Antiviral Drugs - Questions
1.
Discuss the essential differences between a bacterium and a virus.
-
2.
viruses do not have a cell structure while bacteria do
viruses do not have cell wall, bacteria do
viruses are not self-reproducing like bacteria  viruses need living host cells to multiply
viruses do not have metabolic processes (e.g. feed, grow, excrete) while bacteria do
viruses are many times smaller than bacteria
State two reasons why it is difficult to treat viral diseases effectively with antiviral drugs.
- viruses mutate quickly so adapt to drugs or evade immune system response
- viruses multiply rapidly so by the time the disease is identified the viruses are so numerous that
antiviral drugs may have little effect
NOTE: A variation of this question is why viral diseases are more difficult to treat than bacterial
diseases. In this question you would also need to include references to how bacteria are controlled:
- bacteria are more complex and thus can be targeted in more ways while viruses lack subunits
targeted by antibacterials (e.g. enzymes to make cell walls)
bacteria can be killed by simple chemical agents, but viruses cannot be killed and must be
targeted on genetic level
- different types of bacteria employ similar metabolic processes and thus can be targeted by
common antibacterials but each kind of virus usually requires special drugs or approaches
3.
Drugs like acyclovir and ganciclovir are two drugs used to treat diseases caused by the
herpes virus.
acyclovir
ganciclovir
Describe the two main ways in which anti-viral drugs can fight specific viral infections.
-
alter the cells’ genetic material so the virus cannot use it to multiply
e.g. structure of acyclovir is similar to a substance (deoxyguanosine) needed by cells to
make new DNA, but acyclovir will stop DNA replication.
- prevent the newly formed viruses from leaving the host cell
- alter the virus’s binding site on the cell wall
- prevent viruses from multiplying by blocking enzyme activity within host cell
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Chemistry 12 (HL)
4.
Unit 6 / IB Topic D7
AZT (azidothymidine) is used to treat HIV.
a)
Identify the three circled functional groups labelled A, B
and C contained within a molecule of AZT.
A = secondary amide
B = ether
C= hydroxyl
AZT
b)
Explain how AZT stops the HIV virus.
- AZT blocks the enzyme needed to reproduce the HIV genetic material
6.
Discuss the difficulties associated with solving the AIDS problem. (Include sociocultural factors as
well as scientific ones.)
- sociocultural
- failure to use condoms due to cost, cultural resistance, lack of availability
- failure to get tested for HIV or to seek treatment due to social stigma, lack
of education, misinformation
- lack of resources and medical services
- high cost of anti-HIV drugs limits availability
- association with illegal activities like drug use or prostitution may prevent
people from seeking testing or treatment
- scientitic
- rapid mutation of the HIV virus makes it difficult to develop an effective
antiviral drug
- HIV viruses have similar metabolism to (human) cells
- difficult to target HIV without damaging host cell - drugs harm host cell as
well as HIV
- HIV destroys helper cells of the immune system
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