One of the Reasons Scientists Have Had So Much Difficulty

question 55

Multiple Choice

One of the reasons scientists have had so much difficulty finding a cure for HIV/AIDS is that the HIV virus is quick to evolve resistance to the drugs used to treat it. What is the most likely mechanism for this type of evolution?

• A)Certain versions of the virus are slower to die in the presence of a drug than others. Those viruses may survive drug treatment and pass their genes to their offspring.
• B)Every time an HIV drug is taken, it randomly kills off most but not all virus particles. Those that survive repopulate the body of their host.
• C)Although all copies of a particular strain of the HIV virus are identical, some are better at "hiding" in regions of the body that drugs cannot reach, and those viruses "teach" their offspring where to hide.
• D)Some versions of the HIV virus produce chemicals that break down the drugs before they can harm the virus.

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Definitions:

ACh Antagonist

An ACh antagonist is a type of drug that blocks the action of acetylcholine, a neurotransmitter, at its receptor sites, affecting the nervous system's functions.

ACh Agonist

A substance that mimics the action of acetylcholine, a neurotransmitter, thereby stimulating the parasympathetic nervous system.

Curare

A poisonous compound that comes from certain plants, traditionally used on arrow tips in South America for hunting; it blocks nerve impulses to muscles, causing paralysis.

Serotonin Agonist

A type of drug that activates serotonin receptors in the brain, mimicking the effects of serotonin to increase its action in the nervous system.