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Readings 9 notes

Biological Sciences
Course Code
Maydianne Andrade

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Readings 9
-AIDS causes more deaths than TB, malaria, car accidents, homicides and wars
-the AIDS epidemic has wrought its greatest devastation in sub-Saharan Africa
-in industrialized countries of North America and Western Europe, overall infections are much lower
than sub-Saharan Africa
-HIV establishes a new infection when a bodily fluid holding the virus, usually blood or semen, carries it
from an infected person onto a mucus membrane or bloodstream of an uninfected person
-programs to curb the spread of HIV have seen success in promoting reducing risky sexual practices and
condom use
-the increasingly widespread abuse of methamphetamine is associated with risky behaviour and a
greater chance of contracting HIV
-HIV is an intracellular parasite that cannot reproduce on its own
-HIV invade specific types of cells and uses the enzymatic machinery to make copies of itself, killing the
host cell in the process
-during the extracellular phase, the virus moves from host to host
-during the intracellular phase, the virus replicates
-HIV attaches to two proteins on the cell called CD4 and a coreceptor and fuses with the host cell
membrane to spill its contents
-reverse transcriptase transcribes RNA into DNA, integrase splices the DNA genome into the host cell
genome and protease prepares viral proteins
-new virions, after replication, bud off the cell membrane and enter the bloodstream to infect the host
even more or another host
-drugs that interrupt ZÀ]µ[o](Ço]v}]v(Á]ZZZ}oo[vÌÇu](µv]}v
and cause side effects
-HIV parasitizes helper T cells of the immune system that play a crucial role in response to invading
-ZZ}[}Áv]uuµv}vontributes to the development of immunodeficiency
-T cells derive from stem cells in bone marrow and generate precursors that mature in naïve T cells in
the thymus
-an activated T cell yields effector and memory cells that circulate through the blood
-nve and memory T cells are long lived while effector cells are short lived
-in the initial or acute phase of infecti}vU,/sÀ]]}vvZZ}[}ÇvP]v}o]
explosively by killing memory T cells
-the acute phase ends when viral replication slows and the concentration of virions drops due to the
immune system response
-in the chronic phase, the immune system struggles to recover from initial losses while continuing to
fight the virus
helper T cells by stimulating them to divide into effector cells
-replacement of lost helper T cells ultimately depends on the production of new nve T cells by the
capacity to regenerate
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