A disease breaks out among sheep in California. A scientist takes blood from the sheep and grows a previously unknown organism. That organism is then injected into a healthy sheep. The healthy sheep becomes sick with the same symptoms as the original sheep and dies. That sheep's blood is then cultured, and the original organism is isolated. This applies the principles of __________.
a. vaccination
b. spontaneous generation
c. epidemiology
d. Koch's postulates
Answer: d. Koch's postulates
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The above figure is a photograph of
a. plant with root nodules. b. mycorrhizae. c. root hairs. d. demonstration of the effect of mutualistic Rhizobium. e. microscopic view of a nodule forming around area where the bacterium infect.
A bacterial chromosome consists of:
a. a linear DNA molecule many times larger than the cell. b. a circular DNA molecule many times larger than the cell. c. a circular DNA molecule smaller than the cell. d. a linear DNA molecule smaller than the cell. e. a linear or circular DNA molecule smaller than the cell.
Mitochondrial diseases ________
A) are very rare; only a couple of people are diagnosed per year B) are caused only by spontaneous mitochondrial DNA mutations C) cannot be inherited from the mother D) None of the above is true.
In synaptic signaling, neurotransmitters are released into a space that is referred to as a
A. neuron junction. B. paracrine space. C. plasmodesmata. D. gap junction. E. chemical synapse.