Most of the oligotrophic proteobacteria are found in the ________.
A. beta proteobacteria
B. delta proteobacteria
C. gamma proteobacteria
D. alpha proteobacteria
Answer: D
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A serious genetic disorder known as hemochromatosis is often called the rusty organ disease and affects nearly 1.5 million Americans. The disorder causes increased absorption of intestinal iron. Which organ is responsible for iron homeostasis?
A. spleen B. brain C. lungs D. liver E. gallbladder
Which of the following is not a potential mechanism through which sympatric speciation could occur?
a. Host switching b. Habitat differentiation c. Founder effect d. Female mate preference e. Polyploidy
When one plant is shaded by another, why is the ratio of far-red to red light increased compared to an unshaded plant?
A. Phytochrome in the taller plant absorbs most of the red light. B. Auxin absorbs mostly far-red light. C. As light passes through the leaves of the taller plant, most of the red light is absorbed by chlorophyll. D. Far-red light mostly reflects off the surface of the soil while red light is mostly absorbed. E. Shade is enriched in far-red wavelengths of light.
Enzymes generally make good drug targets because a specific reaction of interest can be targeted with a high degree of selectivity
Consider the following three drugs and explain why, although reaction-specific, the first two produce side effects, while the third does not. A. Statins inhibit HMG CoA reductase to block intracellular cholesterol synthesis. B. Methotrexate inhibits dihydrofolate reductase, which subsequently leads to blocked DNA replication. C. Gleevec® inhibits BCR, a kinase that is only produced in certain types of leukemia cells.