Bacteria able to perform the NH4+ + NO2- ? N2 + 2H2O reaction have been discovered in laboratory bioreactors and wastewater treatment systems. Researchers predicted that these bacteria should exist in oceans
They measured the concentration of NH4+, NO2-, NO3-, and O2 in the Black Sea as a function of water depth (M. Kuypers et al. 2003 Anaerobic ammonium oxidation by anammox bacteria in the Black Sea. Nature 422:608-11 ) to determine where in the sea the bacteria might live. Analyzing data presented in the figure above, at what depth would you expect to find the bacteria? (Note: In the figure, different scales are used to show concentrations of NH4+, NO2-, NO3-, and O2.) A) in the top 50 meters
B) at a depth of 75 meters
C) at a depth of 92 meters
D) below 100 meters
C
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The ____________ is a disk-shaped cloud of icy bodies believed to extend from about 40 AU (the orbit of Pluto) out to 100 AU. It is believed that most short-period comets originate from this region
a. Oort cloud b. Widmanstätten cloud c. Apollo-Amor d. Kirkwood region e. Kuiper belt
Blood flows directly from the left atrium to _____
a. the aorta c. the right atrium b. the left ventricle d. the pulmonary arteries
The expression of both alleles for a trait in a heterozygous individual illustrates
A) codominance. B) pleiotropy. C) polygenic inheritance.
A scientist isolates a mutant of a gated ion channel that transports ions into the cell in the presence of a particular chemical signal. She determines that the mutation causes the channel to remain open even in the absence of any chemical signal. She measures concentrations of the ion on either side of the membrane and finds that the concentration is higher inside the cell than outside at the beginning of the experiment. After an hour, she measures the concentrations again. What do you expect she will find?
A) The concentration of the ion has increased inside the cell after an hour. B) The concentration of ion inside the cell is equal to the concentration outside the cell. C) The concentration of the ion has become higher outside the cell than inside the cell after an hour. D) The concentrations of the ion inside and outside of the cell have remained constant. E) The ions have all diffused into the membrane.