The 3-day test that is useful for identifying the rapid-growers, M. fortuitum and M. chelonae, and that measures the rate by which this enzyme breaks down phenolphthalein disulfate into phe-nolphthalein and other salts is the ____________ test
a. niacin.
b. phenolphthalein.
c. arylsulfatase.
d. Tween 80.
C
The enzyme arylsulfatase is present in most mycobacteria. Test conditions can be varied to dif-ferentiate different forms of the enzyme. The rate by which this enzyme breaks down phenolph-thalein disulfate into phenolphthalein, which forms a red color in the presence of sodium bicar-bonate, and other salts helps differentiate certain strains of mycobacteria. The 3-day test is par-ticularly useful for identifying the potentially pathogenic rapid-growers, M. fortuitum and M. chelonae.
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Intrinsically unstructured proteins:
A. have no function because they are unstructured. B. only function in membranes. C. are capable of binding to several different sites on different partners. D. are more common in bacteria than in humans. E. are only observed in diseased cells.
Which statement is true?
a. Morphology no longer informs phylogenetic classification. b. Cnidarians are the only organisms classified as Radiata. c. Phylogenetic trees are hypotheses, and frequently change. d. Mitochondrial DNA is only used to classify extinct organisms.
What is the correct sequence of polypeptide transport in the secretory pathway?
a. plasma membrane ? Golgi bodies ? ER ? ribosome b. plasma membrane ? ER ? Golgi bodies ? ribosome c. ribosome ? Golgi bodies ? ER ? plasma membrane d. ribosome ? ER ? Golgi bodies ? plasma membrane e. Golgi bodies ? ribosomes ? ER ? plasma membrane
What is the potential across a membrane if the overall Gibb's free energy change across the membrane is -19.3 kJ mol-1 and the pH difference across the membrane is 0.70 at 310K? (R = 8.315 J K-1 mol-1; F = 96,485 J V-1 mol-1)
A) -0.16 V B) +.16 V C) -0.24 V D) +0.24 V