Researchers have proposed that the herpesvirus responsible for the childhood illness roseola may cause a type of T cell leukemia. Ninety percent of the population has been infected by the virus by two years of age, but the T cell leukemia is relatively rare. The virus can be cultured in the laboratory in tissue culture, but not in mature organisms. Discuss the obstacles to applying Koch's
postulates to the etiology of this disease.
What will be an ideal response?
Koch's first postulate, that the suspect agent must be present in every case of disease, is met, but far more people have the virus than have the disease. This suggests that more than the presence of the virus is necessary for the leukemia to develop, and the additional factors may be difficult to identify. The third postulate states that the isolated suspect agent must cause disease when introduced into a host. This situation presents two difficulties in satisfying the third postulate. The first is that it is unethical to deliberately expose humans to an agent that may produce life-threatening disease (the leukemia). Additionally, ethical concerns aside, because such a large percentage of the population has been exposed to the virus, a large pool of potential uninfected subjects does not exist.
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Describe three adaptations that enhance the function of a respiratory surface
What will be an ideal response?
How is cytokinesis in plant cells different from cytokinesis in animal cells?
A. Cytokinesis in plant cell results in one large cell with two nuclei; cytokinesis in animal cells results in two cells, each with one nucleus. B. Cytokinesis in plant cells results in haploid cells; cytokinesis in animal cells results in diploid cells. C. Cytokinesis in plant cells occurs during G2; cytokinesis in animal cells occurs in the M phase of the cell cycle. D. Cytokinesis in plant cells requires formation of a cell plate; cytokinesis in animal cells requires formation of a ring of actin.
Urey and Miller's experimental setup was able to produce all twenty of the amino acids found in proteins. Some amino acids contain the element oxygen. What starting material in the Urey-Miller experiment was source of this element?
a) methane b) ammonia c) hydrogen gas d) water e) electrical sparks
Pyruvate
A) forms at the end of glycolysis. B) is the molecule that starts the citric acid cycle. C) is the end product of oxidative phosphorylation. D) is a six-carbon molecule.