12. Phenylketonuria (PKU) is a recessive genetic disease caused by the p allele.
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Question
12. Phenylketonuria (PKU) is a recessive genetic disease caused by the p allele. Based on our discussion of this disease in lecture, which of the following statements is true a) a pp individual will always exhibit the effects of PKU, regardless of the diet that individual is raised on b) a PP will exhibit the effects of PKU if raised on a diet high in phenylalanine c) a pp individual will not exhibit the effects of PKU if raised on a diet low in phenylalanine d) the genotype of a pp individual will change to Pp when raised on a diet low in phenylalanine e) the genotype of a pp individual will change to Pp when raised on a diet high in phenylalanine
13. Which of the following would be an appropriate measure of the phenotypic variation of a trait in a population a) the mean of the trait in the population b) the standard deviation of the trait
c) the heritability of the trait d) the allele frequency of genes affecting the trait.
14. Evolutionary change of a trait in a population under the effect of selection can occur only when
a) VE > 0 b) h2 > 0 c) h2 = 0 d) VE = 0
15. You examine body weight in a laboratory population of mice. You find that individuals fall into five discrete weight classes with mean weights of 15 grams, 20 gr., 25 gr., 30 gr., and 35 gr. The variance of weight within each class is very low, and the distribution of weights in the different weight classes do not overlap. Based on these observations you would conclude that in this population and environment
a) body weight is a quantitative trait b) body weight is a qualitative trait c) body weight is affected by many different genes d) body weight is affected only by environment e) a & d.
16. In sage plants, height is affected by only one gene, T. One hundred seeds of genotype TT are grown in a field. After one month the plants are measured and are found to exhibit a continuous normal distribution of heights ranging from 4 to 12 inches. What can you conclude about this phenotypic variation? a) it must be due to genetic variation alone b) it must be due to environmental variation alone c) it is due to a combination of genetic and environmental variation d) you cannot tell the source of the variation.
17. You bring a sample of flies from a natural population into the laboratory and begin selecting for high body weight by using the heaviest 20% of the population as parents each generation for five generations. If mean body weight remains the same in each generation
a) phenotypic variation is due only to effects of the environment b) phenotypic variation is due only to genetic variation among individuals c) VG > 0 d) VE = 0
18. Given the observations described in the previous question you would conclude that for body weight
a) heritability is zero b) heritability is greater than zero but less than 1 c) heritability is 1 d) heritability is greater than 1
19. The heritability of body weight in cows a) can be measured on a single individual b) is the proportion of VG which is due to VE c) is the proportion of VP which is due to VG d) is the proportion of VE transmitted to offspring e) all of the above.
20. When we say that the heritability of a trait in a particular population is zero a) the trait is not affected by genes b) the trait is not affected by the environment c) all individuals are genetically identical for genes affecting the trait d) individuals differ in genotype for the genes affecting the trait.
21. In the Hardy-Weinberg equilibrium formula (p2 + 2pq + q2), p2 and q2 are
a) genotype frequencies b) fitnesses c) allele frequencies d) numbers of individuals.
22. The reproductive fitness of an individual is determined mainly by
a) strength b) life span c) number of offspring d) owning a BMW
23. In a population with 980 AA, 840 Aa, and 180 aa individuals the genotype frequency of Aa individuals is a) 0.49 b) 0.98 c) 0.42 d) 0.81 e) 0.18
24. The frequency of the A allele in the population above is a) 0.49 b) 0.5 c) 0.6 d) 0.7.
25. There are two alleles B and b in a population. If the frequency of the B allele is 0.75 then the expected number of Bb heterozygotes in a generation consisting of 10,000 individuals under the Hardy-Weinberg equilibrium model would be a) 3750 b) 5625 c) 625 d) 8750 e) 7500.
26. The main usefulness of the Hardy-Weinberg equilibrium is a model in studying evolutionary change in a population is a) it predicts the change in allele frequency over time due to selection can be used as a null hypothesis in a statistical test of whether significant change has occurred b) it provides a prediction of no evolutionary change over time, which can be used as a null hypothesis in a statistical test of whether significant change has occurred c) it predicts the change in allele frequency over time due to genetic drift d) a & b e) a, b, & c.
27. If the fitnesses of genotypes AA, Aa, and aa in a population are 10, 15 and 20 respectively, then over time a) the A allele will increase in frequency due to genetic drift b) the A allele will increase in frequency due to selection c) the a allele will increase in frequency due to selection
d) mutation favors the A allele and will cause it to increase in frequency.
Explanation / Answer
12.) Phenylketonuria is a disease in which metabolism of phenylalanine is affected. A pp individual is not able to metabolise phenylalanine. If he is raised on diet low in phenylalanine then level of phenylalanine will not increase in body.and thus it's symptoms are reduced. Thus we can say option C is correct.
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