In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (Rr) offspring of red (RR) and white (rr) homozygotes. Which of the following crosses would produce offspring in the ratio of 1 red:2 roan:1 white?
A) red × white
B) roan × roan
C) white × roan
D) red × roan
B
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Compared to antibiotics, there are fewer antiviral agents available because ________.
A. viruses are not as deadly as bacteria so research dollars have been spent developing antibacterial drugs B. before drugs were developed that could directly target virus-specific enzymes, it was thought that any antiviral agent would have to target host cell processes, ultimately damaging cells and tissues C. they are much more costly to produce due to the small size of viruses compared to bacteria D. antibiotics are produced by other bacteria, whereas all antivirals have to be synthesized in a laboratory
Li-Fraumeni syndrome is a rare inherited disease that greatly increases a person's risk of developing several types of cancer. This disease stems from a mutation in the TP53 tumor suppressor gene (Nichols et al. 2001
Cancer Epidemiol Biomarkers Prev 10:83-87). In most cases, approximately 95% of the mutations can be detected by sequence analysis of exons 4 through 9. If you isolated and analyzed DNA from a Li-Fraumeni patient, what genotype should you find in DNA isolated from a. normal tissue? b. malignant tissue?
Karl Popper suggested that scientists use "imaginative preconception," which means that successful scientists
A. do not need to do experiments to test their ideas. B. do not keep records of experiments that fail. C. often predict the outcome of experiments. D. cannot predict the outcome of experiments. E. only perform applied research.
Which type of infecting organism causes strep throat?
A. protist B. parasitic worm C. virus D. bacterium E. fungus