Why is it necessary to have a standard for the interpretation of stable isotope ratios?
A) A standard is necessary to calculate how much radioactivity was added to a sample.
B) A standard is necessary to determine the stable isotope ratio in the absence of biological activity.
C) A standard is necessary to determine the weight of each isotopes.
D) A standard is necessary to determine the age of the sample.
Answer: B
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Ascomycetes affect humans in all of the following ways except:
A. ascomycete rusts damage wheat crops. B. ascomycetes are used to produce soy sauce. C. ascomycetes are used to produce penicillin. D. ascomycete yeasts are used to produce beer. E. ascomycetes cause Athlete's foot.
Microwaves do not kill organisms directly but kill by
A. the heat they generate in a product. B. generating free radicals. C. generating toxins. D. creating thymine dimers.
Transcomplementation is a name sometimes given for a test to see whether a gene from one organism can "rescue" a loss-of-function mutant of a different organism with a homologous gene. To which of the following processes might this term apply?
A) replacement of a nonfunctional globin gene with a globin pseudogene B) substitution of a drought-resistant gene from potato plants with a drought-resistant gene from a cactus species C) introduction of a human WEE1 gene into a yeast culture with wee1- mutants D) replacement of a cdc25– with a cdc13+ gene to rescue a cell cycle dysfunction E) use of Drosophila heat shock gene promoters to regulate heat shock genes in fugu
Select the enzyme that does not match the reaction:a
sucrase?splits sucrose into glucose and fructose b. lipase?breaks ester linkages c. phosphatase?removes phosphate groups d. urease?converts urea to ammonia and CO2 e. kinase?breaks peptide bonds