The relative proportion (by weight) of lipid and protein in a membrane:

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#Question id: 4360

#Unit 3. Fundamental Processes

Which of the following functions are characteristic of general transcription factors in eukaryotes?

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#Question id: 4224

#Unit 3. Fundamental Processes

Use the figure to answer the question Refer to the metabolic pathway illustrated. If A, B, and C are all required for growth, a strain mutant for the gene encoding enzyme B would be able to grow on medium supplemented with which of the following nutrient(s)?

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#Question id: 12587

#Unit 10. Ecological Principles

The most plausible  hypothesis to  explain why  species richness is  higher in  tropical  than in  temperate regions is that

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#Question id: 16127

#Unit 13. Methods in Biology

You are studying regulation of the yeast enzyme glutamine synthetase (GS), which is encoded by the GLN1 gene. You have isolated two mutants, designated  gln2– and gln3–, that give decreased GS activity. Mating of either gln2– or gln3– haploids to wild type produces heterozygous diploids that show normal amounts of GS expression. When you cross either a gln2– or gln3– haploid to a gln1– strain the resulting diploids show normal expression of GS.

The GLN1 gene shows a rather complex regulation in response to different amino acids. When either glutamate (glu) or glutamine (gln) is added to the medium, the amount of GS expression diminished and when both glutamate and glutamine are added to the medium GS expression is shut off completely. The effects of different mutants on the response to glu and gln are shown below.

Which of the models from best fits these experimental results? Complete the model for the regulation of GLN1 that includes the effects of glu and gln.      

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#Question id: 18843

#Unit 13. Methods in Biology

Which of the following reagent is used for quantifying DNA