D7 - Antivirals

D.7.1

•State how viruses differ

from bacteria.

List the differences you know of

between bacteria and viruses.

Bacteria

Viruses

List the differences you know of

between bacteria and viruses.

Bacteria

• Microscopic
• Has single, circular

strand of DNA—is able
to manufacture RNA
from the DNA.

• Cell wall
• Can reproduce on its

own.

Viruses

• Submicroscopic
• Has either a section of

DNA or RNA surrounded
by a coat of packed
protein units called
capsomeres.

• No cell wall
• Can’t reproduce without

a living host. Takes over
cell’s machinery to
produce more viruses.

D.7.2

•Describe the different

ways in which antiviral
drugs work.

Describe the different ways in which antiviral

drugs work.

Well known viral infections

• Common cold
• Influenza (Including H1N1)
• HIV/AIDS
• Chicken Pox
• Herpes/warts
What is the body’s natural defense to

viral infections?

Describe the different ways in which antiviral

drugs work.

• Viruses multiply very quickly, so

antiviral drugs will often have little
effect by the time symptoms appear.

• Goal of antiviral drugs is to stop

replication.

Describe the different ways in which antiviral

drugs work.

• Acyclovir is used as a cream or orally

to fight herpes viruses.

• Shortens the time of the outbreak,

but does not prevent recurrences.

• It stops replication of viral DNA, and

prevents virus from multiplying.

Describe the different ways in which antiviral

drugs work.

• Other antiviral drugs prevent new

viruses from leaving the cell.

• Amantadine (C

10

H

17

N) is used to treat

influenza. It inhibits the active site of
an enzyme which helps the virus to
stick to the cell wall.

D.7.3

•Discuss the difficulties

associated with solving the
AIDS problem.

Discuss the difficulties associated with solving the

AIDS problem.

• HIV (Human Immunodeficiency Virus)

can lead to AIDS (Acquired Immune

Deficiency Syndrome).

• HIV attacks white blood cells called T

helper cells (T4-cells).

• HIV therefore destroys the body’s

ability to fight infections, leading to

common infections (pneumonia,

influenza) which can become life

threatening (AIDS).

Discuss the difficulties associated with solving

the AIDS problem.

• The virus is a retrovirus since is

contains RNA instead of DNA.

• It makes viral DNA from RNA using

an enzyme called reverse

transcriptase.

• One of the problems with antiviral

drugs for HIV is the virus is

constantly mutating.

• A drug called AZT has been used to

inhibit the reverse transcriptase, and

this does not affect normal cells.

• AZT has been effective in prolonging

the period until AIDS develops.