Research has demonstrated that neural stem cells have an impaired ...

[awywial]

Research has demonstrated that neural stem cells have an impaired ability to differentiate into functional neurons when subjected to:
 
  a. ethanol.
  b. marijuana.
  c. insufficient nutrients.
  d. poor oxygenation.

Question 2

What characteristic of Prader-Willi syndrome is not a characteristic of Angelman syndrome?
 
  a. It is inherited from the father.
  b. Mental retardation is observable.
  c. Imprinting of an abnormal chromosome 15.
  d. Seizure disorder is present.

[Bsand8]

Answer to Question 1

ANS: A
It has been found that treating cultured neural stem cells with ethanol impairs their ability to dif-ferentiate to functional neurons; this impairment seems to be correlated with aberrant, dense methylation at loci that are active in normal neuronal tissue. The research does not support the effects of marijuana, insufficient nutrition, or poor oxygenation on the stem cell's ability to dif-ferentiate appropriately.

Answer to Question 2

ANS: A
A well-known disease example of imprinting is associated with a deletion of about 4 million base (Mb) pairs of the long arm of chromosome 15. When this deletion is inherited from the father, the child manifests Prader-Willi syndrome, whose features include short stature, hypotonia, small hands and feet, obesity, mild to moderate mental retardation, and hypogonadism. The same 4 Mb deletion, when inherited from the mother, causes Angelman syndrome, which is characterized by severe mental retardation, seizures, and an ataxic gait.