EMB agar is a medium used in the identification and isolation of pathogenic bacteria. It contains digested meat proteins as a source of organic nutrients. Two indicator dyes, eosin and methylene blue, inhibit the growth of gram-positive bacteria and distinguish between lactose fermenting and nonlactose fermenting organisms. Lactose fermenters form metallic green or deep purple colonies, whereas the nonlactose fermenters form completely colorless colonies. EMB agar is an example of which of the following?
A. a selective medium only
B. a differential medium only
C. a selective medium and a chemically defined medium
D. a selective medium, a differential medium, and a complex medium
Answer: D. a selective medium, a differential medium, and a complex medium
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A. Mad cow disease B. Kuru and Creutzfeldt-Jakob Disease C. Scrapie D. All of the choices are correct.
Receptor adaptation occurs when a sensory neuron stops sending impulses even though the original stimulus is still present. Provide several examples of receptors that adapt readily and others that adapt very slowly, if at all
Explain the survival advantage in each of these situations.
Which of the following is an appropriate description of a nucleosome?
a) DNA wrapped around a histone octamer b) DNA wrapped around a kinectochore octamer c) DNA wrapped around a shelterin octamer d) DNA wrapped around a binding protein octamer e)DNA wrapped around a histone octamer + linker DNA
If all the offspring of a testcross are alike and
resemble the organism being tested, then that parent is a. homozygous dominant. b. homozygous recessive. c. heterozygous. d. recessive. e. incompletely dominant.