A 19-year-old intravenous drug user was exposed to the HIV 3 ...

[Mollykgkg]

A 19-year-old intravenous drug user was exposed to the HIV 3 weeks ago and is experiencing a rapid proliferation in viral load. Which of the following statements best captures an aspect of the process of HIV replication that underlies this proliferation?
 
  A)
  Free HIV RNA is able to attach to the cell coat of CD4+ cells.
  B)
  The cytoplasm of CD4+ cells provides a protected environment for the replication of RNA by HIV.
  C)
  Expression of reverse transcriptase by CD4+ cells allows replication of HIV cells rather than new lymphocytes.
  D)
  HIV is able to change its RNA into DNA to allow for replication by CD4+ cells.

Question 2

An 8-week-old boy has been recently diagnosed with a severe combined immunodeficiency (SCID). His parents have performed a significant amount of research on the Internet and have brought a large amount of material to discuss with their care provider.
 
  Which of the following statements best reflects an accurate understanding of their son's health situation?
  A)
  We read that gene therapy could cure our son; we'd like you to look into that option.
  B)
  Our son likely has a deficiency of B lymphocytes and can't produce antibodies.
  C)
  We feel guilty, because dietary and environmental factors have been shown to contribute to SCID
  D)
  The antibodies that our son produces are mismatched to the infections that he was born with and encounters.

[ricroger]

Answer to Question 1

Ans:
D

Feedback:

In order for the HIV to reproduce, it must change its RNA into DNA. It does this by using the reverse transcriptase enzyme. Reverse transcriptase makes a copy of the viral RNA and then in reverse makes another mirror-image copy. The result is double-stranded DNA that carries instructions for viral replication. HIV RNA does not directly attach to CD4+ cells, and RNA is not replicated by HIV itself in the CD4+ cytoplasm. Reverse transcriptase is not produced by CD4+ cells, and CD4+ cells do not directly produce new lymphocytes.

Answer to Question 2

Ans:
B

Feedback:

The pathophysiology of SCID involves normal B cells but a lack of antibody production because of inadequate T-cell help. Gene therapy is not yet a realistic treatment option, and the disease has a genetic basis. Antibodies are not incorrect but rather inadequate in number.

[Mollykgkg]

Excellent

[mochi09]

TYSM