Chapter 9 Lecture Quiz

A couple has two female children. What is the probability that their next child will be male? a. 67% b. 33% c. 25% d. 50%

To determine the phenotype of an individual who expresses a dominate trait, you would cross that individual with an individual who a. is heterozygous for that trait b. is homozygous recessive for that trait c. is homozygous dominant for that trait d. expresses the dominant trait

Which trait is polygenic in humans? a. sickle-cell disease b. blood type c. cystic fibrosis d. height

Which outcome could help you identify a trait whose expression is determined by the effects of two or more genes(polygenic inheritance)? a. pleiotropy occurs b. a mating between a homozygous and a heterozygous individual produces more than the expected number of offspring expressing the dominant trait c. the trait varies along a continuum in the population d. all of the alleles of the gene for that trait are equally expressed

Medel's law are based on the behavior of chromosomes during a. metaphase I and anaphase I of meiosis b. prophase I of meiosis only c. mitotic anaphase d. prophase I and prophase II of meiosis

Attached earlobes are recessive to free earlobes. What genotypic ratio is expected when an individual with attached earlobes mates with an individual heterozygous for free earlobes? a. 1:1 b. 1:2:1 c. 3:1 d. 2:1

A mating between a purebred purple-flowered pea plant and a purebred white-flowered pea plant would produce a(n) ______. a. hybrid b. F2 generation c. P generation d. purebred variety

Round seeds (R) are dominant to wrinkled seeds (r), and yellow seeds (Y) are dominant to green seeds (y). What is the expected phenotypic ratio of a cross between an RrYy and an rryy individual? a. 3:1 b. 1:1:1:1 c. 9:3:3:1 d. 1:2:1

Which technique is used to collect fetal cells during pregnancy for genetic testing? a. amniocentesis b. pedigree analysis c. dihybrid cross d. testcross

Alleles are describes as a. alternate versions of a gene b. environmental factors that affect gene expression c. homologous chromosomes d. alternate phenotypes

Widow's peak, a pointed hairline on the forehead, is a genetic trait caused by a dominant allele. It can be traced back through a family's history using pedigree analysis. The pedigree shown here shows three generations of a family. Notice that some individuals (shown in gray) have a widow's peak (W = dominant allele and w = recessive allele. Mary has the genotype ______. a. ww b. WW c. Ww

What is the specific location of a gene on a chromosome? a. genotype b. locus c. phenotype d. allele

Hypophosphatemia is inherited as a sex-linked dominate trait. The relevant gene is found on the X chromosome. What is the expected outcome of a cross between a homozygous recessive woman and a man with Hypophosphatemia? a. twenty-five percent of their offspring exhibit hypophosphatemia b. fifty percent of their daughters and fifty percent of their sons exhibit hypophosphatemia c. all of their sons and none of their daughters exhibit hypophosphatemia d. all of their daughters and none of their sons exhibit hypophosphatemia

Achondroplasia is a form of dwarfism caused by a dominant allele. The homozygous dominant genotype causes death, so individuals who have this condition are all heterozygotes. If a person with achondroplasia mates with a person who does not have achondroplasia, what percentage of their children would be expected to have achondroplasia? a. 50% b. 75% c. 100% d. 0%

Assume that having three nostrils is inherited as a sex-linked trait on the Y chromosome. A man with three nostrils has a daughter who has a son with a man who has only two nostrils. What is the probability that the three-nostriled man's grandson has three nostrils? a. 50% b. 0% c. 25% d. 100%

What is the key to the recognition of incomplete dominance? a. The phenotype of the heterozygote falls between the phenotypes of the homozygotes. b. The heterozygote expresses the phenotype of both homozygotes. c. The trait exhibits a continuous distribution. d. The alleles affect more than one trait.

What is the key of recognition in codominance? a. The trait exhibits a continuous distribution. b. The phenotype of the heterozygote is intermediate between the phenotypes of the homozygotes. c. The heterozygote expresses the phenotype of both homozygotes. d. The alleles affect more than one trait.

Mendel's Law of Segregation indicates that a. gametes have one allele copy for each gene. b. two alleles segregate into each gamete c. more gametes carrying the dominant allele are produced than gametes carrying the recessive allele d. gametes are diploid

Janice's genotype is a. ww b. WW or Ww c. Ww d. WW

In humans, free earlobes (E) are dominate to attached earlobes (e) and the presence of freckles (F) is dominate to the absence of freckles. If an individual heterozygous for both of these traits were to mate with an individual with attached earlobes and no freckles, what is the probability of having a child with attached earlobes and freckles? a. 0% b. 100% c. 50% d. 25%

In humans, the presence or absence of dimples is a trait controlled by a single gene. What is the genotype of an individual who is heterozygous for dimples? a. Dl b. dd c. DD d. Dd

Which is most commonly found in nature? a. recessive trait b. parental type c. wild-type trait d. dominant trait

Mendel crossed purebred purple-flowered plants with purebred white-flowered plants, and all of the resulting offspring produced purple flowers. The offspring are all ______, and the allele for purple flowers is ______. a. heterozygotes; dominant b. homozygotes; dominant c. heterozygotes; recessive d. homozygotes; recessive

Marfan syndrome is the result of inheriting a single allele. Individuals with Marfan syndrome are tall and long-limbed, and have both cardiovascular and eye defects. Marfan syndrome is an example of a. codominance b. pleiotropy c. incomplete domniance d. homozygous recessive

This hypothetical pedigree for a disease in humans illustrated inheritance that is a. autosomal recessive b. autosomal dominant c. carried on the Y chromosome d. sex-linked dominant

An individual with the blood group genotype LMLN has the phenotype MN. What is the relationship between the LM and LN alleles? a. pleiotropy b. LN is dominant c. codominance d. incomplete dominance

An individual who is heteroxygous for cystic fibrosis a. has cystic fibrosis b. cannot have children with cystic fibrosis c. is a carrier d. will have children who are all carriers of cystic fibrosis

A child is diagnosed with a rare recessively inherited disease. The parents are tested for the gene, and both are found to be heterozygous. The parents want to have another child but are afraid this child will also be affected. What would genetic counselors say is the probability that the second child will have the disease? a. 1/16 b. 1/2 c. 1/8 d. 1/4

Which cross will only produce heterozygous offspring? a. AA x aa b. Aa x Aa c. Aa x aa d. AA x Aa

Red-green colorblindness is inherited as a sex-linked recessive trait. The gene is found on the X chromosome. Can a man with normal color vision father a daughter who us red-green colorblind? a. no, the expression of the trait skips a generation b. yes, if the man is heterozygous for red-green colorblindness c. no, he can't (unless there is a mutation) d. yes, of the woman with whom he mates is red-green colorblind

Many human traits, such as our performance on intelligence tests or our susceptibility to heart disease, are ______. a. determined by genes in some people and by the environment in other people b. determined only by our genes c. influenced by both gene and the environment d. determined solely by environmental factors