Bio test 2

1. Which of the following choices represents the genotype of an individual diploid organism a. BbCCdd c. bcdb. BCd d. BbCd

A. BbCCdd

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 version of a gene

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 b. Ff, Gg, HH c. FG, FH, Fg, fH, fG, fg, GH, gH 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. 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.

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

a. codominant.

Which of the following did Mendel use to help him form the law of independent assortment? a. dihybrid crosses between pea plants b. monohybrid crosses between pea plants c. traits that were codominant 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

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 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.

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 x RRYY b. RRYY x rryy c. RrYy x RrYy d. cannot determine from the information given

b. RRYY x 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 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. 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.

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. d. supports Mendel's law of segregation.

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 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

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.

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

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 b. 500 c. 750 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. d. Mutations will affect the phenotype, which may affect the genotype

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. 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.

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.

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

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 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.

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

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.