The preauricular tags indicative of Goldenhar Syndrome are a result of a defect in which pharyngeal arch?
A. I
B. II
C. III
D. IV
E. VI
Ans: A. I
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During the formation of a blood clot, conversion of prothrombin into the enzyme thrombin requires
A) mitochondria. B) transport of proteins from platelets. C) calcium ions. D) leukocytes. E) albumin.
Which statement correctly interprets the graph? 
A. Paramecium caudatum and Paramecium aurelia are able to compete for the same resource and their population densities are not affected. B. Paramecium aurelia drives Paramecium caudatum to near extinction. C. Paramecium caudatum and Paramecium aurelia are unable to exist and both populations go extinct after 24 days. D. Paramecium caudatum drives Paramecium aurelia to near extinction.
If an X-linked disorder is lethal to the affected individual prior to the age at which one reaches reproductive maturation, the lethality will be expressed only in males. Why is this so?
A) This is not true. We will see the lethality in females as well. B) As it's a lethal allele, it will kill the homozygous recessive first. These are the males. C) The only sources of the lethal allele in the population are heterozygous females who are "carriers" and do not express the disorder. D) At the cellular level, the protein will work less well in the male's cells. E) Because it's sex-limited inheritance, females do not demonstrate the phenotype.
If one wishes to clone a gene using typical restriction endonucleases, how does the restriction endonuclease identify the appropriate cut sites in the genome?
A) The endonuclease identifies its specific recognition sequence. B) The endonuclease cuts randomly in the genome. C) The endonuclease recognizes the gene of interest. D) The endonuclease cannot identify the cut sites.