Chp 14 and 15 Review

1. Chp 14 and 15 Review Multiple Choice Questions

2. If a plant variety is true-breeding for a dominant trait, then _____. � if the plant were allowed to self-pollinate, the dominant and recessive traits would consistently appear in a 3:1 ratio among the progeny � the plant is heterozygous for the trait � if the plant were crossed with a heterozygote, one-half of the progeny would show the dominant trait, and one-half would show the recessive trait � if the plant were allowed to self-pollinate, all of the progeny would have the dominant trait � the variety is immune to mutation

3. If a plant variety is true-breeding for a dominant trait, then _____. � if the plant were allowed to self-pollinate, the dominant and recessive traits would consistently appear in a 3:1 ratio among the progeny � the plant is heterozygous for the trait � if the plant were crossed with a heterozygote, one-half of the progeny would show the dominant trait, and one-half would show the recessive trait � if the plant were allowed to self-pollinate, all of the progeny would have the dominant trait � the variety is immune to mutation

4. Assume tall (T) is completely dominant to dwarf (t). If a homozygous dominant individual is crossed with a homozygous dwarf, the offspring will _____. all be intermediate in height � all be tall � be 1/2 tall and 1/2 dwarf � be 3/4 tall and 1/4 dwarf � all be short

5. Assume tall (T) is completely dominant to dwarf (t). If a homozygous dominant individual is crossed with a homozygous dwarf, the offspring will _____. all be intermediate in height � all be tall � be 1/2 tall and 1/2 dwarf � be 3/4 tall and 1/4 dwarf � all be short

6. In a certain plant, the alleles A, B, and C are completely dominant to the alleles a, b, and c. A plant with the genotype AABbcc will have the same phenotype as a plant with the genotype _____. �Aabbcc � aabbcc � AaBBcc � AABBCc � none of the above

7. In a certain plant, the alleles A, B, and C are completely dominant to the alleles a, b, and c. A plant with the genotype AABbcc will have the same phenotype as a plant with the genotype _____. �Aabbcc � aabbcc � AaBBcc � AABBCc � none of the above

8. In carrying out his breeding studies, Mendel examined characters that had which of the following properties? � They were controlled by loci that were (or behaved as if they were) on different chromosomes. � It was possible to isolate true-breeding varieties for each trait. � The traits varied in an either-or fashion. � The characters each were controlled by a single gene. � All of the above.

9. In carrying out his breeding studies, Mendel examined characters that had which of the following properties? � They were controlled by loci that were (or behaved as if they were) on different chromosomes. � It was possible to isolate true-breeding varieties for each trait. � The traits varied in an either-or fashion. � The characters each were controlled by a single gene. � All of the above.

10. � Homologous pairs of chromosomes often _____. �carry different genes for different traits � differ in length � contain different alleles � are not both present in diploid somatic cells � are paired up in the G2 phase of the cell cycle

11. � Homologous pairs of chromosomes often _____. �carry different genes for different traits � differ in length � contain different alleles � are not both present in diploid somatic cells � are paired up in the G2 phase of the cell cycle

12. A red bull is crossed with a white cow and all of the offspring are roan, an intermediate color that is caused by the presence of both red and white hairs. This is an example of genes that are _____. �nonhomologous � epistatic � codominant � polygenic � completely dominant

13. A red bull is crossed with a white cow and all of the offspring are roan, an intermediate color that is caused by the presence of both red and white hairs. This is an example of genes that are _____. �nonhomologous � epistatic � codominant � polygenic � completely dominant

14. A man who has type B blood and a woman who has type A blood could have children of which of the following phenotypes? A or B only � AB only � AB or O � A, B, or O � A, B, AB, or O

15. A man who has type B blood and a woman who has type A blood could have children of which of the following phenotypes? A or B only � AB only � AB or O � A, B, or O � A, B, AB, or O

16. Which of the following matings cannot produce a child with blood type O? The letters refer to blood types (phenotypes). A x A � A x B � O x AB � O x O � none of the above

17. Which of the following matings cannot produce a child with blood type O? The letters refer to blood types (phenotypes). A x A � A x B � O x AB � O x O � none of the above

18. A single genetic locus that controls more than one trait is said to be _____. polygenic � epistatic � pleiotropic � autotrophic � somatic

19. A single genetic locus that controls more than one trait is said to be _____. polygenic � epistatic � pleiotropic � autotrophic � somatic

20. Tay-Sachs disease runs in Rebecca's family. On a family pedigree, she saw a shaded circle. This represented a _____. male with Tay-Sachs � female carrier � male carrier � female with Tay-Sachs � male of unknown genotype

21. Tay-Sachs disease runs in Rebecca's family. On a family pedigree, she saw a shaded circle. This represented a _____. male with Tay-Sachs � female carrier � male carrier � female with Tay-Sachs � male of unknown genotype

22. Tom's brother suffers from phenylketonuria (PKU), a recessive disorder. The brothers' parents do not have PKU. What are the chances that Tom, who is normal for this trait, is a carrier of PKU? 1/4 � 1/3 � 1/2 � 2/3 � 4/3

23. Tom's brother suffers from phenylketonuria (PKU), a recessive disorder. The brothers' parents do not have PKU. What are the chances that Tom, who is normal for this trait, is a carrier of PKU? 1/4 � 1/3 � 1/2 � 2/3 � 4/3

24. Cystic fibrosis, which is usually lethal before the age of reproduction, is a homozygous recessive trait. Why do cases continue to arise, even though people with the disease rarely live to reproduce? Because new mutations continually introduce this harmful condition into the population. � Because the harmful allele "hides" within heterozygous individuals, one-fourth of the offspring of two heterozygotes would be afflicted. � Because mosquitoes can transfer the disease from person to person. � Because people continue to make inappropriate lifestyle choices. � None of the above.

25. Cystic fibrosis, which is usually lethal before the age of reproduction, is a homozygous recessive trait. Why do cases continue to arise, even though people with the disease rarely live to reproduce? Because new mutations continually introduce this harmful condition into the population. � Because the harmful allele "hides" within heterozygous individuals, one-fourth of the offspring of two heterozygotes would be afflicted. � Because mosquitoes can transfer the disease from person to person. � Because people continue to make inappropriate lifestyle choices. � None of the above.

26. Huntington's disease is an example of a genetic disorder caused by _____. a lethal dominant allele that afflicts an individual later in life � a nonlethal dominant allele � a late-acting recessive allele � homozygous recessive alleles � multiple alleles

27. Huntington's disease is an example of a genetic disorder caused by _____. a lethal dominant allele that afflicts an individual later in life � a nonlethal dominant allele � a late-acting recessive allele � homozygous recessive alleles � multiple alleles

28. Chapter 15

29. Drosophila is a useful organism for genetic studies for all of the following reasons except _____.  They have a long generation time. � A single mating can produce many offspring. � They have a small number of chromosomes. � Drosophila chromosomes can be easily distinguishable under a light microscope. � All of the above

30. Drosophila is a useful organism for genetic studies for all of the following reasons except _____.  They have a long generation time. � A single mating can produce many offspring. � They have a small number of chromosomes. � Drosophila chromosomes can be easily distinguishable under a light microscope. � All of the above

31. Wild type refers to _____. the most common phenotype in the natural population � the most extreme mutant phenotype observed in an experiment � any mutant genotype � a kind of chromosomal deletion � extranuclear genes

32. Wild type refers to _____. the most common phenotype in the natural population � the most extreme mutant phenotype observed in an experiment � any mutant genotype � a kind of chromosomal deletion � extranuclear genes

33. If two genes are linked, _____. they are on different chromosomes � they assort independently � they code for the same protein � they are on the same chromosome � they are on sex chromosomes

34. If two genes are linked, _____. they are on different chromosomes � they assort independently � they code for the same protein � they are on the same chromosome � they are on sex chromosomes

35. The recombination frequency between two gene loci is _____. � dependent on the sex of the parent � greater as the distance between the two loci increases � greater as the distance between the two loci decreases � dependent on whether dominant or recessive alleles are carried at the two loci � equal to the size of the chromosome

36. The recombination frequency between two gene loci is _____. dependent on the sex of the parent � greater as the distance between the two loci increases � greater as the distance between the two loci decreases � dependent on whether dominant or recessive alleles are carried at the two loci � equal to the size of the chromosome