Rickettsiosis is caused by Rickettsia rickettsii, a pathogen that
A. produces powerful exotoxins.
B. provokes a severe immune response.
C. interferes with the host cell's Krebs cycle.
D. infects the lining of blood vessels and leads to leaking of plasma into tissue.
E. lyses the host's cells.
Answer: D
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Narrowing of the arterial lumen due to buildup of lipids is:
a. atrial fibrillation b. atherosclerosis c. a blood clot d. arrhythmia e. angioplasty
For many enzymes, the rate of product formation increases as the concentration of the substrate increases. Eventually the rate of the reaction reaches a maximum at which further increases in the concentration of the substrate have no effect. Why?
A) At high concentrations of substrate, the activation energy of the reaction decreases. B) The enzyme is no longer specific for the substrate. C) At high concentrations of substrate, the reaction is endergonic. D) At high concentrations of substrate, all of the enzyme active sites are being occupied by substrate molecules. E) At high concentrations of substrate, the activation energy of the reaction increases.
Sanitization is a process by which _______.
A. objects are made sterile with chemicals B. hands are scrubbed C. the microbial load on an object is reduced D. skin is debrided
Which of the following is LEAST likely involved in calcium signaling?
A. IP3 B. calmodulin C. protein kinase A D. protein kinase C E. phospolipase C