Chapter Questions
Parents both have unattached earlobes, but some of their children have attached earlobes. Explain, in terms of phenotype and genotype. (pages $466-67$ )
Explain why the gametes have only one allele for a trait. $(\text { page } 467)$
What is the chance of producing a child with the dominant phenotype from each of the following crosses? (pages $469-70$ )a. $A A \times A A$b. $A a \times A A$c. $A a \times A a$d. $a a \times a a$
Which of the crosses in question 3 can result in an offspring with the recessive phenotype? Explain. (pages $469-70$ )
What are the expected results of the following crosses? (pages $469-73$ )a. monohybrid $\times$ monohybridb. monohybrid $\times$ recessivec. dihybrid $\times$ dihybridd. dihybrid $\times$ recessive in both traits
Which of these crosses would best allow you to determine that an individual with the dominant phenotype is homozygous or heterozygous? (pages 470,473 )
What is the genotype of a heterozygote with a widow's peak and short fingers? Give all possible gametes for this individual. (page 472 )
Using a pedigree, show an autosomal recessive disorder pattern and an autosomal dominant disorder pattern. (pages $474-75$ )
What is required for an autosomal recessive disorder to appear? Name four autosomal recessive disorders. What is required for an autosomal dominant disorder to appear? Name two autosomal dominant disorders. (pages $474-77$ )
Define and give an example of each of the following inheritance patterns: polygenic inheritance, multifactorial trait, incomplete dominance, codominance, and multiple alleles. (pages $479-81)$
What are the phenotypes and genotypes for the ABO blood groups? If both parents are type AB blood, what are the possible genotypes and phenotypes for their children, including the expected percentages? (pages $480-81$ )
How is an X-linked trait different from an autosomal trait? (page $481)$
A woman with normal vision reproduces with a man with normal vision. Three sons are color-blind, and one son has normal vision. Explain how this occurred, using the genotypes and gametes of all individuals. (pages $481-82$ )
Which of these is a correct statement?a. Each gamete contains two alleles for each trait.b. Each individual has one allele for each traitc. Fertilization gives each new individual one allele for each traitd. All of these are correct.e. None of these is correct.
Which of the following indicates a heterozygous individual?a. $A B$b. $A A$c. $A a$d. $a a$
What possible gametes can be produced by $A a B b$.a. $A a, B b$b. $A, a, B, b$c. $A B, a b$d. $A B, A b, a B, a b$
In humans, pointed eyebrows $(P)$ are dominant over smooth eyebrows ( $p$ ). Mary's father has pointed eyebrows, but she and her mother have smooth. What is the genotype of the father?a. $p p$b. $P p$c. $P P p p$d. $p P p P$
The genotypic ratio from a monohybrid cross isa. 1: 1.b. 3: 1.c. 1: 2: 1.d. 9: 3: 3: 1.e. 1: 1: 1: 1.
A straight hairline is recessive. If two parents with a widow's peak have a child with a straight hairline, then what is the chance that their next child will have a straight hairline?a. no chanceb. $1 / 4$c. $3 / 16$d. $1 / 2$e. $1 / 16$
What is the chance that an $A a$ individual will be produced from an $A a \times A a$ cross?a. $50 \%$b. $75 \%$c. $0 \%$d. $25 \%$e. $100 \%$
The genotype of an individual with the dominant phenotype can be determined best by reproduction witha. the recessive genotype or phenotype.b. a heterozygote.c. the dominant phenotype.d. the homozygous dominant.e. Both a and b are correct.
The homologous chromosomes align independently at the equator during meiosis soa. all possible combinations of alleles can occur in the gametes.b. only the parental combinations of gametes can occur in the gametes.c. only the nonparental combinations of gametes can occur in the gametes.
What is the chance that a dihybrid cross will produce a homozygous recessive in both traits?a. $9 / 16$b. $1 / 4$c. $1 / 16$d. $3 / 16$e. $1 / 8$
Which of the following is not a feature of multifactorial inheritance?a. Effects of dominant alleles are additive.b. Genes affecting the trait may be on multiple chromosomesc. Environment influences phenotype.d. Recessive alleles are harmful.
The ABO blood system exhibitsa. codominance.b. multiple alleles.c. incomplete dominance.d. Both a and b are correct.
Assume two normal parents have a color-blind son. Which parent is responsible for color blindness in the son?a. the motherb. the fatherc. either parentd. Neither parent-two normal parents cannot have a color- blind son.
If a child has type $\mathrm{O}$ blood and the mother is type A, then which of the following could be the blood type of the child's father?a. A onlyb. B onlyc. O onlyd. A or Oe. A, B, or O
Under what condition(s) will an autosomal recessive disorder appear?a. inheritance of a single recessive alleleb. inheritance of one dominant and one recessive allelec. inheritance of two recessive allelesd. Both a and c are correct.
Alice and Henry are at the opposite extremes for a multifactorial trait. Their children willa. be bell-shaped.b. be a phenotype typical of a 3: 1 ratio.c. have the middle phenotype between their two parents.d. look like one parent or the other.
Two wavy-haired individuals (neither curly hair nor straight hair are completely dominant) reproduce. What are the chances that their children will have wavy hair?a. $0 \%$b. $25 \%$c. $50 \%$d. $100 \%$