A 25-year-old medical student spent a summer volunteering in the sub-Saharan region of Africa. There he noted a high incidence of people reporting difficulty with night vision due to a lack of vitamin A in their diet. Vitamin A is a precursor for the synthesis of

#Question id: 2008

#Unit 4. Cell Communication and Cell Signaling

An immune response to a tissue graft will differ from an immune response to a bacterium because

#Question id: 2009

#Unit 4. Cell Communication and Cell Signaling

A child is diagnosed with DiGeorge syndrome (DGS). With which of the following would the child have serious immunological problems?

#Question id: 2010

#Unit 4. Cell Communication and Cell Signaling

Which of the following might be a child with Brutonʹs disease?

#Question id: 2011

#Unit 4. Cell Communication and Cell Signaling

Brutonʹs disorder might occur because of which of the following molecular problems?

#Question id: 2012

#Unit 4. Cell Communication and Cell Signaling

The DGS-like phenotype can be produced in a specific knockout mouse for HA3, a Hox gene. HA3 is known to be involved in developmental regulation in the mouse. Which of the following would be an appropriate test for following the gene in the mouse progeny?

#Question id: 2013

#Unit 4. Cell Communication and Cell Signaling

A patient undergoes a high level of mast cell degranulation, dilation of blood vessels, and acute drop in blood pressure. These symptoms could be caused by which of the following?