Name_______________________ Date________________Mendelian Genetics SI

A) 0% B) 25% C) 50% D) 75% E) 100%

1. In sheep, eye color is controlled by a single gene withtwo alleles. When a homozygous brown-eyed sheepis crossed with a homozygous green-eyed sheep,blue-eyed offspring are produced. If the blue-eyedsheep are mated with each other, what percent of theiroffspring will most likely have blue eyes?

A) AA, aa B) Aa, aaC) Aa, Aa D) aa, aaE) AA, Aa

2. One hundred and twenty offspring are counted in agenetic cross. Ninety appear to show the dominantphenotype and thirty appear recessive. What are themost likely genotypes of the parents?

A) the genetic makeup of an organismB) part of a chromosome that codes for a certain

hereditary traitC) the outward, visible expression of the hereditary

makeup of an organismD) the shifting of gene positions in chromosomesE) a sequence of three adjacent nucleotides that

codes for a single amino acid

3. A genotype can be described as

A) 100% B) 75% C) 50% D) 25% E) 0%

4. Two parents are heterozygous for dominant trait Aand recessive trait a. If they mate, the probability ofproducing an offspring who displays the dominanttrait is

A) determines whether a dominant-appearingindividual is homozygous dominant orheterozygous dominant for that trait

B) suggests that the unknown dominant-appearingindividual is homozygous if any of the test-crossoffspring are recessive

C) suggests that the unknown dominant-appearingindividual is heterozygous if none of thetestcross offspring are recessive

D) is used to determine whether an individual ishomozygous recessive or homozygous dominantfor a given trait

E) is used to determine whether or not a trait issex-linked

5. A testcross

A) segregationB) codominanceC) mutationD) incomplete dominanceE) independent assortment

6. Two plants with pink flowers are crossed, and the F1show the following ratio: 1 red: 2 pink: 1 white. Thebest explanation for this phenomenon is

A) 0% B) 25% C) 50% D) 75% E) 100%

7. A particular flower inherits color via incompletedominance. A cross between a homozygous blueflower (BB) and a homozygous red flower (RR)yields 100% purple flowers. If a cross between apurple flower and a red flower is performed, whatpercentage of the progeny will be purple flowers?

A) Linked genesB) Incomplete dominanceC) Multiple allelesD) CodominanceE) Polygenetic inheritance

8. In reference to blood types, sometimes both the Aallele and the B allele are expressed. Which of thefollowing terms best explains this?

A) LinkageB) EpistasisC) CodominanceD) Incomplete DominanceE) Multiple Alleles

9. When two inherited alleles are expressed at the sametime, which of the following is exhibited?

A) Multiple allelesB) Sex-linked traitsC) Recessive traitsD) Polygenic inheritanceE) Incomplete dominance

10. Blood types are an example of

A) ii B) IAi C) IBIB D) IAIB

11. Which genotype illustrates codominance of allelesthat control blood type in humans?

A) overproduction and selective breedingB) mutations and elimination of genesC) evolution and asexual reproductionD) sorting and recombination of genes

12. The puppies shown in the photograph below are allfrom the same litter.

The differences seen with this group of puppies aremost likely due to

A) intermediate inheritanceB) gene linkageC) independent assortmentD) crossing-over

13. A cross between two mice with long tails and brownfur produced the four types of offspring listed below:

long tailed with brown furlong tailed with white furshort tailed with brown furshort tailed with white fur

Which genetic mechanism best explains the resultsof this cross?

A) 25% B) 50%C) 75% D) 100%

14. If two roan cattle are crossed, what percent of theoffspring are expected to show the parentalphenotype for coat color?

A) multiple allelesB) incomplete dominanceC) sex linkageD) independent assortment

15. A boy has brown hair and blue eyes, and his brotherhas brown hair and brown eyes. The fact that theyhave different combinations of traits is bestexplained by the concept known as

A) 0 B) 2 C) 3 D) 4

16. In humans, the gene for polydactyly (having extrafingers or toes) is dominant over the gene for thenormal number of digits. If parents who are bothhomozygous dominant for polydactyly have fourchildren, how many of these children would mostlikely have extra fingers or toes?

A) 100% GgB) 50% GG and 50% ggC) 25% GG, 50% Gg, and 25% ggD) 75% Gg and 25% gg

17. In a certain species of mouse, gray fur (G) isdominant over cream-colored fur (g). If ahomozygous gray mouse is crossed with acream-colored mouse, the genotype of the F1 generation will most likely be

A) homozygous dominantB) heterozygousC) hybridD) homozygous recessive

18. Kernel color in corn is a trait determined by twoalleles. The dominant allele (P) produces a purplecolor, and the recessive allele (p) produces a yellowcolor. The diagram below shows an ear of cornproduced by crossing two corn plants. The shadedkernels are purple, and the unshaded ones areyellow.

What can the yellow kernels best be described as?

A) GG × Gg B) GO × GOC) Gg × gg D) gg × gg

19. In squirrels, the gene for gray fur (G) is dominantover the gene for black fur (g). If 50% of a largelitter of squirrels are gray, the parental cross thatproduced this litter was most likely

A) 0% B) 25%C) 75% D) 100%

20. In a population of dogs, curly hair is dominant overstraight hair. If two parents are heterozygous for thistrait, what is the probability that any of theiroffspring will have straight hair?

A) DD andDd B) Dd and DdC) DD and DD D) Dd and dd

21. In dogs, wire hair (D) is dominant over smooth hair(d). If two wire-haired dogs produce asmooth-haired pup, the genotypes of the parent dogsare most likely

A) 0 B) 50 C) 100 D) 200

22. The gene for tallness (T) is dominant over the genefor shortness (t) in pea plants. A homozygousdominant pea plant is crossed with a heterozygouspea plant, and 200 seeds are produced.Approximately how many of these seeds can beexpected to produce plants that are homozygousdominant?

A) 100 % yellowB) 100% whiteC) 50% yellow, 50% whiteD) 25% yellow, 75% white

23. In summer squash, white-colored fruit is dominantover yellow-colored fruit. If homozygousyellow-fruited plants are crossed with heterozygouswhite-fruited plants, what is the expected percentageof fruit color produced in the offspring?

A) 25% B) 50%C) 75% D) 100%

24. In pea plants, the trait for tall stems is dominant overthe trait for short stems. If two heterozygous tallplants are crossed, what percentage of the offspringwould be expected to have the same phenotype asthe parents?

A) TTYY B) Ttyy C) ttYy D) TtYy

25. The chart below indicates a method of representingtraits in pea plants.

Some offspring of a cross in pea plants were tall andgreen. According to the chart, these plants could berepresented by

26. Base your answer to the following question on thePunnett square below which shows the crossbetween two squash plants.

A) codominanceB) intermediate inheritanceC) independent assortmentD) dominance

Which genetic principle is best illustrated by thephenotype of the offspring?

A) 0% B) 25%C) 50% D) 100%

27. In watermelon plants the allele for solid green fruit (G) is dominant over the allele for striped fruit (g).Pollen from a flower of a homozygous greenwatermelon plant is used to pollinate a flower from aheterozygous green watermelonplant. What percent of the offspring of this cross willbear striped watermelons?

A) hybrid B) codominantC) autosomal D) sex-linked

28. Which term best describes genes carried only on the X-chromosome?

A) Bb × bb and Bb × BbB) Bb × bb and BB × BbC) BB × Bb and BB × bbD) BB × BB and Bb × Bb

29. B represents the dominant allele for a trait and b represents the recessive allele. In which pair ofcrosses must all of the offspring produced have thesame phenotype?

A) homozygous redB) homozygous whiteC) heterozygous redD) heterozygous pink

30. A geneticist wishes to determine if a red rose of acertain variety is homozygous for the color red. Ifred is dominant over white, the red rose should becross-pollinated with roses of the same variety thatare

A) Intermediate inheritance involved alleles thatwere not clearly dominant or recessive.

B) Mutations occurred during gametogenesis.C) Crossing-over of white and red alleles occurred

during meiosis.D) Nondisjunction of homologous pairs of

chromosomes resulted in the production ofabnormal offspring.

31. A cross between two plants that have pink flowersproduced plants that have red, pink, or whiteflowers. Which is the most likely explanation forthese results?

A) 3:1 B) 2:1:2 C) 2:1 D) 1:2:1

32. Two generations of offspring of four o'clock plantsare shown in the diagram below.

The phenotypic ratio of the F2 generation is

A) multiple allele inheritanceB) crossing-overC) sex linkageD) codominance

33. Crosses between white-coated cattle (CWCW) andred-coated cattle (CRCR) produce roan offspring (CR

CW). This type of inheritance pattern is known as

Base your answers to questions 34 and 35 on theinformation and diagram below and on yourknowledge of biology.

In cats, gene E produces yellow fur and gene B produces black fur. A cat that inherits both ofthese genes has patches of yellow and black furand is known as a calico. The alleles for black oryellow are located on the X-chromosome. Thecross XBY × XBXE is illustrated in the square below.

A) codominant autosomal genesB) codominant sex-linked genesC) recessive autosomal genesD) recessive sex-linked genes

34. Calico coat color is most likely due to

A) 1 B) 2 C) 3 D) 4

35. Yellow male offspring are represented by

A) the genetic makeup of autosomes found in theegg cell

B) the genetic makeup of autosomes found in thesperm cell

C) whether the unfertilized egg contains an X- or Y-chromosome

D) whether the sperm that fertilizes the eggcontains an X- or Y-chromosome

36. The sex of a person depends on

A) 22 autosomes and one X-chromosomeB) 22 autosomes and one Y-chromosomeC) 44 autosomes and XX-chromosomesD) 44 autosomes and XY-chromosomes

37. A normal human egg cell contains

A) The production of testosterone influences thedevelopment of male characteristics.

B) Reproductive technology has had an importantinfluence on human development.

C) Normal female characteristics develop from asingle X-chromosome.

D) Male characteristics only develop in theabsence of X-chromosomes.

38. The Y-chromosome carries the SRY gene that codesfor the production of testosterone in humans.Occasionally a mutation occurs resulting in the SRYgene being lost from theY-chromosome and added tothe X-chromosome, as shown in the diagram below.

Based on the diagram, which statement is correct?

A) XRXR × XRY B) XRXR × XrYC) XRXr × XrY D) XrXr × XRY

39. In fruit flies, red eye color (R) is dominant and whiteeye color (r) is recessive. The allele for eye color iscarried on the X-chromosome. Which cross wouldmost likely produce 50% white-eyed males and 50%red-eyed males?

A) 0% B) 25%C) 50% D) 100%

40. A man with normal color vision married a womanwith normal color vision. The father of the womanwas colorblind. If this couple had a daughter, what isthe chance this child would be colorblind?

Answer KeyMendelian Genetics SI

1. C2. C3. A4. B5. A6. D7. C8. D9. C10. A11. D12. D13. C14. B15. D16. D17. A18. D19. C20. B21. B22. C23. C24. C25. B26. D27. A28. D29. C30. B31. A32. D33. D34. B35. D36. D

37. A38. A39. C40. A