Chapter 12: Patterns of Inheritance

1.	Alleles are alternate forms of a gene. The alleles for the gene that determines blood type in humans are found at __________. [Hint]
2.	Humans have about 35,000 genes. How many alleles of each of these genes are present in your muscle cells, disregarding genes on the X and Y chromosomes? [Hint]
3.	If a plant is true-breeding for a flower color, it is __________ for the flower-color gene. [Hint]
4.	A Punnett square is __________. [Hint]
5.	If a gene has alleles that are incompletely dominant, an individual that is heterozygous at this locus will have characteristics that are __________. [Hint]
6.	Which one of the following statements is true? (For extra practice, try to change the incorrect answers to make them correct statements. Also, give an example for each of the correct statements.) [Hint]
7.	Cystic fibrosis is a recessive trait. Imagine that your friend Roger has cystic fibrosis but that his parents do not. What do you know about Roger's alleles and those of his parents at the cystic fibrosis locus of their DNA? [Hint]
8.	Anne Boleyn, King Henry VIII's second wife, was beheaded because she did not provide him with a son as an heir. Explain why King Henry should have blamed himself and not his wife. [Hint]
9.	In many cases, conditions that occur more frequently in males than in females are due to sex-linked inheritance. Male pattern baldness is more common in males than in females, but that is not because of sex-linked inheritance. Suggest a possible explanation. [Hint]
10.	Labrador retrievers may have yellow fur, chocolate brown fur, or black fur. Coat color is determined by two genes that have two alleles each. One gene, called E, determines whether the dog’s fur is dark or light, with the dark allele (E) dominant to the light allele (e). The other gene, called B, determines whether the dark fur will be black or chocolate, with the black allele (B) dominant to the chocolate allele (b). If you mate two chocolate labs together, what color puppies can they have? [Hint]
11.	A couple brings home their new, nonidentical twin daughters, Joan and Jill. After several months, the father begins to suspect that there was a mix-up at the hospital, because Jill doesn’t look much like either parent or like her sister. When the twins' blood tests come back, the father calls his lawyer to start a lawsuit against the hospital. The mother, father, and Joan have type A blood, but Jill has type O blood. Does the father have a case? Explain your answer. (The gene for blood type has three alleles: A, B, and O. The A and B alleles are codominant, and the O allele is recessive.) [Hint]
12.	What are alleles? [Hint]
13.	Consider this hypothetical example: If you were to apply Mendel's reasoning to the past presidential election, and hanging chads (C) were dominant to pregnant chads (c), which of the following genotypes would result in the expression of the dominant phenotype from a cross of F1 offspring that are Cc? [Hint]
14.	What does Mendel's law of independent assortment tell us about the behavior of genes during meiosis? [Hint]
15.	If an organism has only three chromosomes, how many chromosomes are autosomes? [Hint]
16.	A single gene capable of influencing multiple phenotypes within a single organism is said to be __________. [Hint]
17.	What is the root cause of sickle-cell anemia? [Hint]
18.	If the pea plants I planted this year all have red flowers, and the parent of those seeds also had red flowers, those seeds are said to be . [Hint]
19.	In Mendel's experiments, he first cross-bred true breeding purple-flowered peas with true breeding white-flowered peas. The first filial generation was found to consist entirely of -flowered pea plants. [Hint]
20.	Mendel found that the F1 generation in his pea plant experiments looked like only one of the original parent plants, but that the flower color trait exhibited by the other parent showed up again in F2. He suggested that purple flower color was with respect to flower color in peas. [Hint]
21.	When one trait usually expresses itself in conjunction with another, and the genes which control that expression are found on the same chromosome, those two traits are genetically . [Hint]
22.	Sometimes, chromosomes will exchange stretches of DNA during a crossing-over event. This occurs at a . [Hint]
23.	When true breeding snapdragons with red flowers are cross-bred with true breeding white-flowered snapdragons, the progeny exhibit a color between white and red. This is because red and white have dominance over each other. [Hint]
24.	In the diagram below, the capital P stands for purple, and the small p indicates white. This is an example of complete dominance. Label each of the F2 offspring according to their color, as indicated by their genotype. [Hint] For each item below, use the pull-down menu to select the letter that labels the correct part of the image. Choice A Choice B Choice C purple, heterozygote Choice A Choice B Choice C white, homozygote Choice A Choice B Choice C purple, homozygote
25.	Fill in the missing genotype for each of the eggs across the top of the Punnett square below. [Hint] For each item below, use the pull-down menu to select the letter that labels the correct part of the image. Choice A Choice B Choice C Choice D SY Choice A Choice B Choice C Choice D sy Choice A Choice B Choice C Choice D sY Choice A Choice B Choice C Choice D Sy
26.	Human eye color is a trait that shows incomplete or mixed dominance. Using the clues given in the Punnett square below, complete the genotypes of the offspring on the diagonal. [Hint] For each item below, use the pull-down menu to select the letter that labels the correct part of the image. Choice A Choice B Choice C Choice D AABB Choice A Choice B Choice C Choice D aabb Choice A Choice B Choice C Choice D AAbb Choice A Choice B Choice C Choice D aaBB
27.	Which of the following can account for a situation where Mendel's Law of Independent Assortment fails to hold? [Hint]
28.	Some people are said to be "carriers" of genetic disorders. What does this mean? [Hint]
29.	Which of the following is true of a man with hemophilia? [Hint]
30.	What happens if a baby has only one X chromosome, and no Y? [Hint]
31.	Which of the following is caused by an abnormal number of autosomes? [Hint]
32.	Mendel's experiments with dihybrid crosses led him to develop his law of . [Hint]
33.	Geneticists study patterns of inheritance in human families to learn about genetic diseases. A chart showing how a trait is inherited over several generations of a family is called a . [Hint]
34.	Heterozygous individuals are of recessive genetic disorders. [Hint]
35.	Errors in meiosis that cause a gamete to have too few or too many chromosomes are called . [Hint]
36.	A person with XO sex chromosomes has syndrome. [Hint]
37.	An organism is described as Rr:red. The Rr is the organism’s [A]; red is the organism’s [B]; and the organism is [C].
38.	The 9:3:3:1 ratio is a ratio of
39.	A lawyer tells a male client that blood type cannot be used to his advantage in a paternity suit against the client because the child could, in fact, be the client’s, according to blood type. Which of the following is the only possible combination supporting this hypothetical circumstance? (Answers are in the order mother:father:child.)
40.	A heterozygous red-eyed female Drosophila mated with a white-eyed male would produce
41.	Which is NOT true of sickle-cell anemia?
42.	Sex-linked disorders such as color blindness and hemophilia are
Answer choices in this exercise are randomized and will appear in a different order each time the page is loaded.