Evolution Ch 1 Certification Exam Questions And Answers Verified Solutions.
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AZT
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AZT
Why study evolution? - correct answer understanding evolution can help us know ourselves and our origins. Evolutionary biology is the conceptual foundation for all of life science. The tools and techniques of evolutionary biology offer crucial insights ...
Why study evolution? - correct answer understanding evolution can help us
know ourselves and our origins. Evolutionary biology is the conceptual foundation for all of life science.
The tools and techniques of evolutionary biology offer crucial insights into matters of life and death.
Where is AIDS affecting human populations the most significantly? - correct answer
The epidemic has been most devastating in sub-saharan Africa, where 1 in 20 adults are living with HIV.
In 1980s spokesmen and expert was Anthony Fauci (infectious disease)
How does AIDS compare to other major causes of death worldwide? What are the major causes of death
worldwide? - correct answer AIDS causes about 3.1% of all deaths worldwide.
AIDS is responsible for fewer deaths than heart disease, strokes, and lower respiratory tract infections,
but it causes more deaths that TB, lung and other respiratory cancers, and traffic accidents.
Who are high-risk populations for having AIDS in the US? - correct answer Men
who have sex with men and those who use drugs via injections with needles (sharing)
How is HIV spread? - correct answer A new HIV infection starts when a bodily
fluid carries the virus from an infected person directly contacts a mucous membrane or into the
bloodstream of an uninfected person. HIV travels via semen, vaginal, and rectal secretions, blood, and
breast milk. It can move during homosexual or heterosexual sex, oral sex, needle sharing, transfusion
with contaminated blood products, other unsafe medical procedures, childbirth and breastfeeding.
Is HIV a retrovirus? What is a retrovirus? - correct answer HIV is a retrovirus. A
retrovirus is a virus that uses RNA instead of DNA as genetic material when replicating and invading the
host cell (uses reverse transcriptase - viral RNA to DNA - embed it and use the cells processes to
replicate)
How does HIV enter a host cell? What is contained in the virion? What are the usuals host cells? What
roles do reverse transcriptase and integrate play in the HIV life cycle? - correct answer
HIV vision encounters a host cell (usually a helper T cell). The HIV gp120 surface protein with bind to CD4
then a co-recceptor CCR5 not eh host cell. Virion then fuses with the host cell and the HIV genome and
enzymes enter the host cytoplasms. Reverses transcriptase will syntehsize HIV DNA from eh RNA
, template. Then integrate splices the HIV DNA into the host genome and goes through the replication
process and translation/transcription for precursor proteins for new virons.
Why are viral diseased difficult to treat? - correct answer HIV and other viral
diseases in general are so difficult to treat because it is a challenge to find drugs that interrupt the viral
cycle without also disrupting the host cells enzymatic functions and thus causing debilitating side effects.
How does HIV cause AIDS? When does the patient get AIDS? - correct answer
Different strains of HIV exploit different co-receptors but most strains are responsible for new infections
use a protein called CCR5. Cells that carry both CD4 and CCR5 on their membranes and are thus
vulnerable to HIV, including macrophages, effector helper T cells, and memory helper T cells. The AIDS
phase begins when the concentration of CD4 T cells in the blood drops below 200 cells per cubic
milimeter. By now the patients immune system has begun to collapse and can no longer fend off a
variety of opportunistic viruses, bacteria and fungi. HIV infections deplete the patients CD4 T cells and
undermines the patients immune system.
How can HIV be stopped before it leads to AIDS? - correct answer To stop it
from replicating. The first drug to do so, azidothymidine or AZT, was approved for therapeutic use in
1987 targeting reverse transcriptase.
Why was AZT looked at as a promising drug to treat HIV infection initially? - correct answer
AZT stops reverse transcriptase. AZT is structured similarly to the nucleotide thymidine (T), so RT will
pick up AZT instead of T. The biggest difference between T and AZT is the lack of OH group on AZT where
the next nucleotide would be added. Because the OH is not there teh RT cannot continue building the
DNA thus interrupting the path to new viral proteins. Early tests it worked, haunting the loss of T cells
but it caused side effects because it acted on our own polymerase sometimes.
What does the T start for in AZT? what makes HIV resistant to AZT? - correct answer
Thymidine. HIV is resistant to AZT by random mutations that made it resistant and then would pass it on
to the next generation.
How does mutated reverse transcriptase become resistant to AZT? - correct answer
2 ways the mutated RT became resistant to AZT; by avoiding AZT or having inserted AZT into the
growing DNA strand then taking it back out.
How error-prone is HIV's reverse transcriptase? - correct answer It is very
error-prone because thousands of generations of HIV replication takes place within each patient during
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