A current problem in modern medicine is the development of drug resistance mutations. This occurs when a mutation arises in a disease-causing microbe making it resistant to a drug and thus rendering the drug useless in treating a specific disease. Many useful drugs are competitive inhibitors of specific enzymes, and the drug-resistance mutations prevent the binding of the drug. These types of mutations, in addition to preventing competitive inhibitor binding, can also sometimes reduce the activity of the enzyme. Why is that the case?
A. These mutations most likely affect an allosteric site on the enzyme
B. These mutations lower the activation energy of the reaction catalyzed by the enzyme
C. These mutations most likely change the shape of the active site of the enzyme
D. Binding to the competitive inhibitor is essential for the function of the enzyme
Answer: C
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a. Unchanging b. Change over time c. Immediate change d. all the above
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A) electron transport chain B) fermentation C) glycolysis D) Krebs cycle
Which statement describes an important similarity between chickenpox and smallpox?
A) Both are treatable with antiviral therapy. B) Both have a similar mortality rate of about 30%. C) Both involve the formation of a vesicular rash. D) Vaccinations against both are recommended for all children. E) Both are caused by viruses which lie dormant in nerve cells and be reactivated later in life.
Disruptive selection favors
a. the intermediate forms. b. an extreme at one end of a range of variation. c. the extremes at both ends of a range of variation. d. a greater number of individuals in the center of the bell-shaped curve. e. neutral traits.