Bio Chapter 6

PRINT - The figure shown illustrates a.the law of independent assortment. b.the law of segregation. c.a dihybrid cross. d.a monohybrid cross.

b.the law of segregation.

Which of the following choices represents the genotype of an individual diploid organism? a. BbCCdd b. BCd c.bcd d.BbCd

a. BbCCdd

If two different alleles for the same trait have an equal effect on the phenotype, the alleles are a. codominant. b.recessive. c.epistatic.

a. codominant.

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.

a.Environmental conditions under which plants are grown can cause variations in phenotypes.

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

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.

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.

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.

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. b.pleiotropy. c.codominance. d.incomplete dominance.

a.epistasis.

Mendel used ________ as his research organism to study patterns of genetic inheritance. a.garden peas b.snapdragons c.mice d.Siamese cats

a.garden peas

What is the smallest number of traits that are needed to test Mendel's law of independent assortment? a.one b. two c.four d.eight

b. two

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 b.25 percent c.50 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.

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.

b.Cross the plant to a plant with green leaves.

In a particular plant, two genes control leaf shape and color. Round leaves (R) aredominant 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

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.

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.

b.The sperm cell would contain only one allele for a given gene; the skin cell would contain two alleles.

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.

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.

b.Two organisms with the same genotype are homozygous.

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. b.incomplete dominance. c.multiple gene effects. d.environmental effects on genes.

b.incomplete dominance.

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.

b.neither supports nor disproves Mendel's law of independent assortment.

In Mendel's controlled mating experiments the individuals produced by crossing two true-breeding parents are referred to as a.the P generation. b.the F1 generation. c.the F2 generation. d.dihybrids.

b.the F1 generation.

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.

b.the skeletal traits are related in the overall function of the dog.

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 most likely affected by environmental factors in addition to genes.

b.these diseases are most likely affected by environmental factors in addition to genes.

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.

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 b.25 percent c.50 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

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.

c.Mutations will affect the genotype, which may affect the phenotype.

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.

c.The separation of alleles for one gene does not affect the separation of alleles for other genes.

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.

c.There are two genes to control two separate steps in a pathway.

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.

Most human genetic characters are a.controlled by one gene. b.not inherited according to Mendel's laws. c.controlled by more than one gene. 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. b.codominance. c.epistasis. d.independent assortment.

c.epistasis.

PRINT: 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. b.white. c.gray. d.black with white stripes.

c.gray.

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. b.a polygenic trait. c.pleiotropy. d.codominance.

c.pleiotropy.

The observation that individuals afflicted with albinism also always have vision problems is an example of a.codominance. b.incomplete dominance. c.pleiotropy. 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

A thoroughbred racehorse could have at most ________ alleles of the same gene. a. 16 b.8 c.4 d.2

d. 2

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.

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.

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.

PRINT: 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

Mendel's laws of segregation and independent assortment both have their biological basis in events that take place during a.chromosome formation. b.mutation. c.mitosis. d.meiosis.

d.meiosis.

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.