Biology Test # 2 Study Guide
Which of the following represents all of the possible gametes that can be formed by an individual with the genetic makeup FfGgHH? a. FGH, FgH, fGH, fgH c. FG, FH, Fg, fH, fG, fg, GH, gH b. Ff, Gg, HH d. FfGhHH, FFGGHH, ffgghh
a. FGH, FgH, fGH, fgH
A ________ is a chart that shows genetic relationships within a family over several generations. a. karyotype c. Punnett square b. pedigree d. single-gene disorder map
b. pedigree
Which of the following statements regarding genes is NOT true? a. Genes are located on chromosomes. b. Genes consist of a long sequence of DNA. c. Genes are the basic unit of information affecting a genetic trait. d. In sexually reproducing species, each cell contains a single copy of every gene.
d. In sexually reproducing species, each cell contains a single copy of every gene.
Which of the following genotypes represents a human male? a. XY c. XX b. YY d. XO
a. XY
Which of the following did Mendel use to help him form the law of independent assortment? a. dihybrid crosses between pea plants c. traits that were codominant b. monohybrid crosses between pea plants d. traits with incomplete dominance
a. dihybrid crosses between pea plants
Two genes control fur color in Labrador retrievers. The first gene determines whether the pigment to be deposited in the hairs will be black or brown. The second gene determines whether the pigments are put into the dog's hairs at all. A dog homozygous for the recessive allele of this second gene will be yellow because no pigment is deposited in its hairs. This is an example of a. epistasis. c. codominance. b. pleiotropy. d. incomplete dominance.
a. epistasis.
The X chromosome in humans is a. found as a pair in females. c. present only in females. b. the only human sex chromosome. d. always found in single copy.
a. found as a pair in females.
Most inherited human genetic disorders are inherited as ________ alleles. a. dominant c. homologous b. recessive d. sex-linked
b. recessive
What is the smallest number of traits that are needed to test Mendel's law of independent assortment? a. one c. four b. two d. eight
b. two
A pea plant that is heterozygous for the flower color gene makes gametes. What is the probability that a specific gamete contains the recessive allele for flower color? a. 0 percent c. 50 percent b. 25 percent d. 75 percent
c. 50 percent
What information is NOT visible in a karyotype? a. the individual's sex b. the number of autosomes c. whether the individual carries genetic mutations d. whether deletions have occurred
c. whether the individual carries genetic mutations
A thoroughbred racehorse could have at most ________ alleles of the same gene. a. 16 c. 4 b. 8 d. 2
d. 2
Mendel's laws of segregation and independent assortment both have their biological basis in events that take place during a. chromosome formation. c. mitosis. b. mutation. d. meiosis.
d. meiosis.
1. Which of the following choices represents the genotype of an individual diploid organism? a. BbCCdd c. bcd b. BCd d. BbCd
a. BbCCdd
Which of the following statements explains how genetically identical plant clones can exhibit dramatic phenotypic variation? a. Environmental conditions under which plants are grown can cause variations in phenotypes. b. Plants undergo mutations to adapt to temperature extremes. c. Plants are able to shut off genes that are not adaptive in their current environment. d. Genetically identical plants cannot have different phenotypes.
a. Environmental conditions under which plants are grown can cause variations in phenotypes.
Which of the following did Gregor Mendel notice in garden peas? a. Some plants always produced offspring with flowers that were the same color as the parent plant's flowers. b. The first generation from a genetic cross of true-breeding plants always produced offspring that were intermediate in their phenotype and did not look like either parent. c. Garden peas always produce a variety of phenotypes in their offspring, which result from frequent mutations. d. Any individual pea plant carries at least three different alleles for flower color.
a. Some plants always produced offspring with flowers that were the same color as the parent plant's flowers.
In which of the following situations would it become nearly impossible to predict the phenotype of an individual with a known genotype? a. The environment affects the phenotype. b. The genotype of the parents is unknown. c. The genotype of offspring is unknown. d. You should always be able to predict the phenotype if you know the genotype.
a. The environment affects the phenotype.
Which of the following genetic changes would NOT be passed from parent to child? a. a mutation in a skin cell b. the loss of a chromosome in a sperm cell c. the addition of a chromosome in an egg cell d. a translocation in a gamete
a. a mutation in a skin cell
An allele is a. a version of a gene. b. a trait that can be affected by the external environment. c. always codominant to its counterpart in another chromosome. d. the result of a change in phenotype.
a. a version of a gene.
The parents in the figure shown are carriers of a genetic disorder. Based on the Punnett square, the allele that causes the disorder must be a. autosomal. c. dominant. b. sex-linked. d. incompletely dominant.
a. autosomal.
Chromosomes that are NOT involved in determining gender are known as a. autosomes. c. homologues. b. sex chromosomes. d. linked.
a. autosomes.
If two different alleles for the same trait have an equal effect on the phenotype, the alleles are a. codominant. c. epistatic. b. recessive. d. incompletely dominant.
a. codominant.
Mendel used ________ as his research organism to study patterns of genetic inheritance. a. garden peas c. mice b. snapdragons d. Siamese cats
a. garden peas
The pedigree shown diagrams an X-linked gene. The individual indicated is ________ for the gene. a. heterozygous b. homozygous c. autosomal d. There is not enough information to determine the answer.
a. heterozygous
Chapter 8 --- The two strands of a DNA molecule are held together by ________ bonds between their base pairs. a. hydrogen c. phosphate b. amino acid d. protein
a. hydrogen
A karyotype shows a chromosomal abnormality that does not change the length of any of the chromosomes. Which abnormality is indicated? a. inversion c. translocation b. deletion d. duplication
a. inversion
The karyotype shown is from a(n) a. male. c. individual of undetermined sex. b. female. d. individual with a genetic disorder.
a. male.
Most inherited human disorders are the result of a. recessive mutations of genes located on autosomes. b. dominant mutations of genes located on the X chromosome. c. recessive mutations of genes located on the Y chromosome. d. simultaneous mutations of the same gene on homologous chromosomes.
a. recessive mutations of genes located on autosomes.
If two parents are heterozygous for an autosomal recessive disease, a. they are both considered genetic carriers for the disease. b. their children have no chance of inheriting the disease. c. their children have a 50 percent chance of inheriting the disease. d. all of their children will also be heterozygous.
a. they are both considered genetic carriers for the disease.
On chromosomes within an individual, there are ________ alleles for a given gene found on ________ chromosomes. a. two; homologous c. four; paternal b. four; maternal d. two; Y
a. two; homologous
Humans have ________ pairs of homologous chromosomes. a. 46 c. 22 b. 23 d. 44
b. 23
Consider a gene with two alleles that show complete dominance. When two heterozygotes for this gene breed, they have a 25 percent chance of producing a homozygous recessive offspring. The next time these two individuals breed, what are the chances that they will once again have a homozygous recessive progeny? a. 0 percent c. 50 percent b. 25 percent d. 75 percent
b. 25 percent
The coat color in a Siamese cat is determined by a temperature-sensitive allele that allows the brownish pigment melanin to be produced in extremities of the body. What might explain this phenomenon? a. Melanin appears darker in extremities because less light is reflected. b. Alleles are used to produce proteins that function best in specific temperature ranges. c. Siamese cats evolved in warm climates and did not need melanin. d. Extremities in a cat are more prone to damage from sunlight.
b. Alleles are used to produce proteins that function best in specific temperature ranges.
The leaf color of a certain plant is controlled by one gene. For that gene, the allele G = orange and g = green. You have a plant with orange leaves, but do not know whether that plant's genotype is GG or Gg. Which of the following would help you determine the plant's genotype? a. Cross the plant to another plant with orange leaves. b. Cross the plant to a plant with green leaves. c. Cross two true-breeding, orange-leaved plants to each other and then cross one of their offspring to the plant with the unknown genotype. d. Change the environment in which the plant grows to find the conditions that cause the leaves to produce the orange color.
b. Cross the plant to a plant with green leaves.
Why are X-linked recessive genetic disorders more commonly seen in males? a. For an X-linked disorder to occur, an individual must receive one allele only found on the X chromosome and a second allele found only on the Y chromosome, which females do not have. b. Females must receive two copies of the recessive allele to exhibit the disorder, but males need only one copy. c. The alleles of sex-linked genes are carried only on the Y chromosome, which females do not have. d. Females only have X chromosomes and genes on the X chromosome are not expressed.
b. Females must receive two copies of the recessive allele to exhibit the disorder, but males need only one copy.
If a father is affected by an X-linked condition and the mother is a carrier, what is the probability of their children being affected? a. All sons will be affected. c. All daughters will be affected. b. Half of the sons will be affected. d. Half of the sons will be carriers.
b. Half of the sons will be affected.
Which of the following statements would indicate a pedigree that shows the inheritance pattern of a recessive X-linked disease? a. Most affected individuals are females. c. Males and females are affected equally. b. Most affected individuals are males. d. The disease is seen in every generation.
b. Most affected individuals are males.
Because an individual with an XX genotype is a female, is an individual with an XO (no second sex chromosome) a male? a. No, because the X always overrides the Y and makes that embryo female. b. No, because the Y chromosome contains the gene that makes an embryo male. c. Yes, because if there is only one X, the embryo cannot become female. d. Yes, because all embryos start off as males.
b. No, because the Y chromosome contains the gene that makes an embryo male.
In a particular plant, two genes control leaf shape and color. Round leaves (R) are dominant to jagged leaves (r). Yellow fruits (Y) are dominant to white fruits (y). A true-breeding round-leaved, yellow-fruited plant is mated with a jagged-leaved, white-fruited plant. What are the genotypes of the plants involved in this cross? a. RRYY RRYY b. RRYY rryy c. RrYy RrYy d. cannot determine from the information given
b. RRYY rryy
Why did Mendel analyze thousands of plants while conducting his research? a. To allow him to control the environment of his pea plants. b. The likelihood of seeing a clear pattern is higher with a larger data set. c. Mendel knew that chromosomes undergo recombination during meiosis. d. To eliminate the probability of mutations affecting his data.
b. The likelihood of seeing a clear pattern is higher with a larger data set.
Two organisms that are true-breeding for a certain genetic characteristic are mated and their offspring analyzed. Which of the following statements about this situation is true? a. Both parents are heterozygotes. b. The offspring are either 100 percent homozygotes or 100 percent heterozygotes. c. The offspring represent the P generation. d. The gametes produced by the offspring will carry two alleles for this gene.
b. The offspring are either 100 percent homozygotes or 100 percent heterozygotes.
If you compare a sperm cell in a human to a skin cell from the same individual, which of the following differences would you expect to find? a. The sperm cell would contain four alleles for a given gene; the skin cell would contain two alleles. b. The sperm cell would contain only one allele for a given gene; the skin cell would contain two alleles. c. Both sperm and skin cells may carry different alleles for an individual gene. d. Both sperm and skin cells would contain 46 chromosomes found as homologous pairs.
b. The sperm cell would contain only one allele for a given gene; the skin cell would contain two alleles.
Which of the following statements about homologous chromosomes is true? a. There are 46 pairs in humans. b. They contain the same genes in the same locations. c. They contain identical alleles in the same location. d. They are also known as sex chromosomes.
b. They contain the same genes in the same locations.
Which of the following expresses Mendel's law of segregation? a. All dominant alleles of different genes divide into different cells from the recessive alleles. b. Two alleles of a gene separate during meiosis and end up in different gametes. c. When gametes form, the genes originally from one parent all end up in different gametes from the genes originally from the other parent. d. Gametes with recessive alleles will fuse only with each other.
b. Two alleles of a gene separate during meiosis and end up in different gametes.
5. Which of the following statements is NOT true? a. Two organisms with the same phenotype may have different genotypes. b. Two organisms with the same genotype are homozygous. c. A heterozygous organism may have the same phenotype as a homozygous organism. d. A heterozygous organism has fewer alleles for a given gene than a homozygous organism.
b. Two organisms with the same genotype are homozygous.
Chapter 7 --- Two copies of the same gene on a single chromosome would indicate a(n) ________ had occurred. a. deletion c. inversion b. duplication d. translocation
b. duplication
In the pedigree shown, the individual indicated represents a(n) a. healthy male. c. affected male. b. healthy female. d. affected female.
b. healthy female.
A carrier is an individual with a ________ genotype who does not express the recessive trait but can pass it along to offspring. a. homozygous c. recessive b. heterozygous d. dominant
b. heterozygous
A chestnut-colored horse is mated with a cremello (cream-colored) horse. Over a 10-year period, all of their offspring are palominos. This pattern of inheritance is best explained by a. complete dominance. c. multiple gene effects. b. incomplete dominance. d. environmental effects on genes.
b. incomplete dominance.
27. In a genetic cross of Gg with Gg guinea pigs, none of the four offspring were gg. This a. disproves Mendel's law of independent assortment. b. neither supports nor disproves Mendel's law of independent assortment. c. supports Mendel's law of independent assortment. d. supports Mendel's law of segregation.
b. neither supports nor disproves Mendel's law of independent assortment.
The genetic disorder followed through the pedigree shown is a. recessive and X-linked. c. dominant and X-linked. b. recessive and autosomal. d. dominant and autosomal.
b. recessive and autosomal.
. In Mendel's controlled mating experiments the individuals produced by crossing two true-breeding parents are referred to as a. the P generation. c. the F2 generation. b. the F1 generation. d. dihybrids.
b. the F1 generation.
The figure shown illustrates a. the law of independent assortment. c. a dihybrid cross. b. the law of segregation. d. a monohybrid cross.
b. the law of segregation.
The pleiotropy that occurs when a single gene controls multiple skeletal traits in dogs, such as leg bone length and skull size, may be explained because a. dogs share a common ancestor. b. the skeletal traits are related in the overall function of the dog. c. dogs have lived with humans for thousands of years. d. the effect of this gene depends on the environment.
b. the skeletal traits are related in the overall function of the dog.
In a karyotype of a male, which of the following would indicate an abnormality? a. one X chromosome and one Y chromosome b. three copies of chromosome 22 c. 22 pairs of autosomes d. a total of 46 chromosomes
b. three copies of chromosome 22
Mendel's manuscript discussing his pea-breeding results is considered one of the two most important scientific papers of the nineteenth century because he was the first to explain how a. mutations produced the variety of alleles displayed by individuals of the same species. b. traits are passed from one generation to the next. c. meiosis controls the distribution of alleles to each gamete. d. genes are arranged on chromosomes in the cell.
b. traits are passed from one generation to the next.
Sickle-cell disease is an inherited chronic blood disease caused by an autosomal recessive allele. Suppose a man who is homozygous recessive for the sickle-cell gene fathers a child by a woman who is a carrier for sickle-cell. What are the chances their children will exhibit the disease? a. 0 percent c. 50 percent b. 25 percent d. 75 percent
c. 50 percent
Suppose D were dominant and d were recessive, and you could label the D allele in the P generation with a radioactive substance that could be inherited over several generations. You create hybrids by mating your radioactive DD individuals to dd individuals. Finally, you cross two F1 individuals (with the Dd genotype). In 1,000 offspring, how many would you predict would be radioactive? a. 250 c. 750 b. 500 d. 1,000
c. 750
A person is genetically XX and develops as a male. How can this be explained? a. In humans, males are XX. b. An error in karyotyping this individual must have occurred because XX individuals cannot develop into a male. c. A piece of a Y chromosome has become attached to one of the X chromosomes. d. The SRY gene was deleted in this individual.
c. A piece of a Y chromosome has become attached to one of the X chromosomes.
If a genetic disorder is caused by a dominant allele, individuals with which of the following genotypes would be affected by the disorder? a. AA and aa c. AA and Aa b. aa and Aa d. AA, Aa, and aa
c. AA and Aa
Which of the following must be true for a woman who is heterozygous for a given gene? a. She must be heterozygous for all genes. b. All of her eggs will contain both of the alleles for that gene. c. All of her eggs will contain one allele or the other, but not both alleles. d. She carries a rare mutation.
c. All of her eggs will contain one allele or the other, but not both alleles.
Which of the following is true for mutations? a. Mutations will affect the genotype without affecting the phenotype. b. Mutations will affect the phenotype without affecting the genotype. c. Mutations will affect the genotype, which may affect the phenotype. d. Mutations will affect the phenotype, which may affect the genotype.
c. Mutations will affect the genotype, which may affect the phenotype.
What information in a pedigree would indicate a condition is likely dominant? a. Twenty-five percent of the individuals in the pedigree have the condition. b. Two-thirds of the affected individuals are females. c. None of the affected individuals have unaffected parents. d. Most of the affected individuals are males.
c. None of the affected individuals have unaffected parents.
In humans, the "master sex switch" that determines whether an embryo will become a male is the a. X chromosome. c. SRY gene. b. locus. d. androgen switch.
c. SRY gene.
If a recessive allele causes a fatal disease that kills the affected individual before he or she can reproduce, why doesn't that allele quickly become extinct in the population? a. Alleles are never lost from a population. b. The homozygous dominant individuals protect the recessive allele in their genomes. c. The recessive allele is carried in the genome of heterozygotes, who do not suffer from the disease. d. The homozygous recessive individuals give their alleles to other individuals before they die from the disease.
c. The recessive allele is carried in the genome of heterozygotes, who do not suffer from the disease.
Which of the following statements is a basic summary of one of Mendel's laws? a. All beneficial human genetic traits are dominant and harmful traits are recessive. b. The pattern of inherited characteristics of organisms is not predictable. c. The separation of alleles for one gene does not affect the separation of alleles for other genes. d. Recessive alleles cause the death of the gamete.
c. The separation of alleles for one gene does not affect the separation of alleles for other genes.
The gene for a certain sex-linked trait is found only on the Y chromosome. If the male parent carries this gene, which of the following statements about the inheritance of that trait is true? a. The trait will be expressed in 100 percent of the female offspring. b. The trait will be expressed in 50 percent of the female offspring. c. The trait will be expressed in 100 percent of the male offspring. d. The trait will be expressed in 50 percent of the male offspring.
c. The trait will be expressed in 100 percent of the male offspring.
Which of the following is true of the genetic cross shown in the figure? a. All of their daughters will be carriers. b. Their sons have a 50 percent chance of being carriers. c. Their sons have a 50 percent chance of having the disorder. d. Their daughters have a 50 percent chance of having the disorder.
c. Their sons have a 50 percent chance of having the disorder.
Which of the following might explain how two separate genes control a single trait? a. Both genes have the same alleles. b. One gene functions better at higher temperatures. c. There are two genes to control two separate steps in a pathway. d. Two genes cannot control a single trait.
c. There are two genes to control two separate steps in a pathway.
Autosomal dominant diseases are exhibited by anyone who carries at least one dominant allele for that gene. How is it that dominant lethal genes, such as the one that causes Huntington disease, can persist in a population? a. The disease-causing allele can "hide" in the heterozygous condition. b. The disease develops only under the influence of other genes. c. These diseases usually take effect later in life after people have had children. d. The environment plays a large role in determining whether the gene is expressed.
c. These diseases usually take effect later in life after people have had children.
Which of the following statements is true of Mendel's laws? a. They are less accurate than Punnett square results. b. They are useful only in unusual situations. c. They correctly explain how genes are inherited. d. They correctly predict the phenotype of an organism.
c. They correctly explain how genes are inherited.
The figure shown indicates two Labrador retrievers that are both homozygous recessive for fur color. Why is one dog brown and the other is yellow? a. This is an example of pleiotropy. b. This is an example of codominance. c. This is an example of epistasis. d. This is an example of incomplete dominance.
c. This is an example of epistasis.
A karyotype from an adult male indicates a chromosomal abnormality, which does not affect his health. Which of the following abnormalities is most likely seen? a. three copies of the X chromosome b. no copies of chromosome 2 c. a translocation between chromosome 14 and chromosome 15 d. a deletion on chromosome 5
c. a translocation between chromosome 14 and chromosome 15
Most human genetic characters are a. controlled by one gene. c. controlled by more than one gene. b. not inherited according to Mendel's laws. d. not heritable.
c. controlled by more than one gene.
We need a hammer to pound nails into a board. Even if we have the nails, we cannot pound them without first getting hold of a hammer. This is similar to the genetic relationship known as a. heterozygosity. c. epistasis. b. codominance. d. independent assortment.
c. epistasis.
In the Punnett square shown below, the lettered circles on the top and left of the square (indicated by the arrows) represent the a. offspring that will be produced by the cross. b. genotypes of the parents involved in the cross. c. gametes that may be produced by each parent involved in the cross. d. offspring that could be produced by the cross.
c. gametes that may be produced by each parent involved in the cross.
Feather color in a certain species of bird is controlled by a pair of alleles that exhibit incomplete dominance. If birds that are homozygous for one allele are black and birds that are homozygous for the other allele are white, then heterozygous birds would be a. black. c. gray. b. white. d. black with white stripes.
c. gray.
Which of the following information is available in a Punnett square showing the inheritance pattern for an autosomal recessive disorder? a. percentage of males likely to be affected by the disorder b. percentage of females likely to be affected by the disorder c. percentage of all children likely to be affected by the disorder d. number of children born to the two parents
c. percentage of all children likely to be affected by the disorder
One of the first medical tests a newborn receives determines if the child has phenylketonuria (PKU). PKU is the result of a mutation in a single gene that causes mental retardation and a host of other phenotypes (light hair and skin color, eczema, and a "mousy" smell). By detecting PKU early, doctors are able to reduce the effect of this condition with a modified diet. PKU is an example of a. epistasis. c. pleiotropy. b. a polygenic trait. d. codominance.
c. pleiotropy.
The observation that individuals afflicted with albinism also always have vision problems is an example of a. codominance. c. pleiotropy. b. incomplete dominance. d. epistasis.
c. pleiotropy.
Which of the following does NOT represent a phenotype? a. a person's susceptibility to Addison's disease b. the height of a draft horse c. the alleles in a mouse that control hair color d. the extent to which an individual is shy
c. the alleles in a mouse that control hair color
Which of the following is the mechanism described by Mendel that results in a new combination of alleles in a pea plant seed? a. the mutation of multiple alleles during mitosis b. the mutation of multiple alleles during meiosis c. the separation of alleles for two different genes during meiosis d. the separation of alleles for a single gene during meiosis
c. the separation of alleles for two different genes during meiosis
Among children with parents who are both carriers of Tay-Sachs, an autosomal recessive disorder, chances are that a. 75 percent will be carriers. b. 50 percent will die in a few years. c. 75 percent will not carry the recessive Tay-Sachs's allele. d. 50 percent will be carriers.
d. 50 percent will be carriers.
Which of the following would explain two chromosomes in an individual cell that contain some, but not all, of the same genes at the same loci? a. Both of the chromosomes are paternal. b. Both of the chromosomes are maternal. c. The chromosomes are from a common ancestor. d. A chromosomal alteration has occurred.
d. A chromosomal alteration has occurred.
Which of the following statements is NOT true? a. Traits that are determined by the effect of more than one gene are known as polygenic. b. Environmental factors can alter the effects of genes. c. Most traits are under the control of more than one gene. d. A genotype is always expressed in the phenotype.
d. A genotype is always expressed in the phenotype.
Both members of a couple are carriers for a recessive disease allele. If the couple has four children, which of the following statements must be true? a. One of the children has the disease. b. Two of the children have the disease. c. All of the male children have the disease. d. Fifty percent of the children could be carriers of the disease.
d. Fifty percent of the children could be carriers of the disease.
During cell division a piece of a chromosome breaks off and reattaches to the same chromosome, but the piece is now in reverse order. How would this abnormality affect the chromosome? a. An extra copy of the chromosome will be made to ensure normal function. b. The inverted section will be deleted to prevent problems. c. The chromosome will take on a circular configuration. d. Genes in the section that was inverted could lose normal function.
d. Genes in the section that was inverted could lose normal function.
A karyotype of an individual with mild mental retardation shows three copies of the X chromosome. If this individual decides to have children, how is her chromosomal abnormality likely to affect her offspring? a. All of her children will inherit an extra copy of the X chromosome. b. Any female children have a 75 percent chance of inheriting an extra copy of an X chromosome. c. She will be unable to produce male children. d. Half of her eggs will contain an extra copy of the X chromosome.
d. Half of her eggs will contain an extra copy of the X chromosome.
Would it be necessary to have both the genotype and phenotype for an organism if you are attempting to predict the inheritance pattern for a trait, such as hair color, in offpsring? a. Yes; individuals with different genotypes often have the same phenotype. b. Yes; individuals with different phenotypes often have the same genotype. c. No; knowing the phenotype will indicate the genotype. d. No; knowing the genotype will indicate the phenotype.
d. No; knowing the genotype will indicate the phenotype.
In which of the following situations would looking at a pedigree be most useful? a. An adopted boy is admitted to the hospital with recurrent vomiting. b. A young girl is born with diminished hearing and a cleft palate. c. Six unrelated individuals with similar symptoms are admitted to the hospital in a one-week period. d. Three young boys who are first cousins show symptoms of a neurological disorder.
d. Three young boys who are first cousins show symptoms of a neurological disorder.
A female who is a carrier of the sex-linked gene A has the genotype a. Aa. c. aa. b. AA. d. XAXa.
d. XAXa.
If the male in generation II was affected, what would the pattern of inheritance most likely be? a. X-linked recessive c. autosomal recessive b. X-linked dominant d. autosomal dominant
d. autosomal dominant
The 9:3:3:1 ratio of phenotypes that occurs in the F2 generation of the cross shown can be explained using a. blending inheritance. b. Mendel's law of segregation only. c. Mendel's law of independent assortment only. d. both of Mendel's laws of genetic inheritance.
d. both of Mendel's laws of genetic inheritance.
When Mendel proposed the law of segregation, which of the following pieces of information did he NOT have? a. data on the outcomes of crossing two true-breeding pea plants b. ratios to predict the outcome of crossing two heterozygous pea plants c. a prediction for how a single trait is inherited d. knowledge of the location of the alleles for flower color
d. knowledge of the location of the alleles for flower color
A Punnett square is used to a. determine the source of new alleles. b. determine how many genes control a given trait. c. predict the gametes that will be produced by an organism. d. predict the outcome of a genetic cross.
d. predict the outcome of a genetic cross.
An allele that appears more frequently in males is most likely a. dominant. c. autosomal. b. nonhomologous. d. sex-linked.
d. sex-linked.
The gender of a human child is determined by the a. loci. c. autosomes. b. egg. d. sperm.
d. sperm.
In humans, X-linked genetic diseases a. are associated with autosomes. b. tend to be expressed more in females than males. c. only affect males. d. tend to be expressed more in males than in females.
d. tend to be expressed more in males than in females
One chromosomal abnormality that is usually fatal is a. a mutation in a gene. b. an exchange of material between homologous chromosomes. c. extra copies of sex chromosomes. d. the addition of an extra autosomal chromosome.
d. the addition of an extra autosomal chromosome.
The figure shown indicates two diseases with genetic links that are common in industrialized nations. The fact that both are about 80-90% avoidable indicates that a. people are most likely avoiding having children with individuals who are affected by these diseases. b. these diseases are Mendelian traits that are expressed more frequently in industrialized nations where the average lifespan is longer. c. industrialized nations are able to use more resources to track these diseases in populations. d. these diseases are most likely affected by environmental factors in addition to genes.
d. these diseases are most likely affected by environmental factors in addition to genes.
