AP CH11

Name:

AP CH11

Multiple Choice

Identify the letter of the choice that best completes the statement or answers the question.

In Mendel's time, most people believed that

a.	all genetic traits bred true.
b.	only certain forms of domesticated plants and animals bred true.
c.	the characteristics of parents were blended in the offspring.
d.	acquired characteristics were inherited.
e.	the inheritance of traits was controlled by blood.

Which of the following is NOT a characteristic of the pea plants with which Mendel worked?

a.	They produced male and female parts.
b.	They exhibited blending inheritance.
c.	They would normally self-fertilize.
d.	They had many different traits and exhibited some pure-breeding varieties.
e.	They could be easily cross-fertilized by human manipulation.

A locus is

a.	a recessive gene.
b.	an unmatched allele.
c.	a sex chromosome.
d.	the location of an allele on a chromosome.
e.	a dominant gene.

Gene A occurs on chromosome #5, gene B occurs on chromosome #21. Therefore, these two portions of the chromosomes CANNOT be

a.	genes.
b.	dominant.
c.	loci.
d.	alleles.
e.	recessive.

Which of the following descriptions of Mendel is INCORRECT?

a.	He was simply lucky to work out the laws of genetics.
b.	He focused on contrasting phenotypic characteristics.
c.	He demonstrated that the blending theory of inheritance was wrong.
d.	He kept exact mathematical data and was the first scientist to utilize numerical analysis of results.
e.	He was a monk, a science teacher, and a gardener.

Short hair (L) is dominant to long hair (l). If a short-haired animal of unknown origin is crossed with a long-haired animal and they produce one long-haired and one short-haired offspring, this would indicate that

a.	the short-haired animal was pure-breeding.
b.	the short-haired animal was not pure-breeding.
c.	the long-haired animal was not pure-breeding.
d.	the long-haired animal was pure-breeding.
e.	none of these can be determined with two offspring.

The theory of segregation applies most specifically to events occurring in preparation of

a.	offspring.
b.	zygotes.
c.	homologous chromosomes.
d.	gametes.
e.	loci.

The theory of segregation

a.	deals with the alleles governing two different traits.
b.	applies only to linked genes.
c.	applies only to sex-linked genes.
d.	explains the behavior of a pair of alleles during meiosis.
e.	none of these

If Mendel had not examined the __________ generation, he would not have discovered his theory of segregation.

a.	P₁
b.	H₁
c.	A₁
d.	F₁
e.	F₂

10.

The F₂ phenotypic ratio of a monohybrid cross is

a.	1:1.
b.	2:1.
c.	9:3:3:1.
d.	1:2:1.
e.	3:1.

11.

A testcross involves

a.	two F₁ hybrids.
b.	an F₁ hybrid and an F₂ offspring.
c.	two parental organisms.
d.	an F₁ hybrid and the homozygous dominant parent.
e.	an F₁ hybrid and an organism that is homozygous recessive for that trait.

12.

For monohybrid experiments, a testcross could result in which of the following ratios?

a.	1:1
b.	2:1
c.	9:3:3:1
d.	1:2:1
e.	3:1

13.

If all the offspring of a testcross are alike and resemble the organism being tested, then that parent is

a.	homozygous dominant.
b.	homozygous recessive.
c.	heterozygous.
d.	recessive.
e.	incompletely dominant.

14.

Individuals with the genotype Gg Hh Ii Jj will produce how many different kinds of gametes?

a.	2
b.	4
c.	6
d.	8
e.	16

15.

In cocker spaniels, black coat color (B) is dominant over red (b), and solid color (S) is dominant over spotted (s). If a red male was crossed with a black female to produce a red spotted puppy, the genotypes of the parents (with male genotype first) would be

a.	Bb Ss x Bb Ss.
b.	bb Ss x Bb Ss.
c.	bb ss x Bb Ss.
d.	bb Ss x Bb ss.
e.	Bb ss x Bb ss.

16.

In cocker spaniels, black coat color (B) is dominant over red (b), and solid color (S) is dominant over spotted (s). If a red spotted male was crossed with a black solid female and all the offspring from several crosses expressed only the dominant traits, the genotype of the female would be

a.	BB SS.
b.	Bb SS.
c.	Bb Ss.
d.	BB Ss.
e.	none of these

17.

In cocker spaniels, black coat color (B) is dominant over red (b), and solid color (S) is dominant over spotted (s). If two black solid dogs were crossed several times and the total offspring were eighteen black solid and five black spotted puppies, the genotypes of the parents would most likely be

a.	Bb Ss x Bb Ss.
b.	Bb Ss x Bb SS.
c.	BB Ss x Bb ss.
d.	BB Ss x Bb Ss.
e.	Bb ss x Bb SS.

18.

In cocker spaniels, black coat color (B) is dominant over red (b), and solid color (S) is dominant over spotted (s). If two dihybrids (Bb Ss) were crossed, the most common phenotype would be

a.	black and solid.
b.	black and spotted.
c.	red and solid.
d.	red and spotted.
e.	none of these

19.

In cocker spaniels, black coat color (B) is dominant over red (b), and solid color (S) is dominant over spotted (s). In the F₂ generation of a cross between BB ss with bb SS, what fraction of the offspring would be expected to be black and spotted?

a.	1/16
b.	9/16
c.	1/9
d.	3/16
e.	3/4

20.

In the second generation of a cross of DD RR with dd rr, the most common genotype would be

a.	DD RR.
b.	Dd RR.
c.	Dd Rr.
d.	dd RR.
e.	dd Rr.

21.

The theory of independent assortment

a.	cannot be demonstrated in a monohybrid cross.
b.	is illustrated by the behavior of linked genes.
c.	indicates that the expression of one gene is independent of the action of another gene.
d.	states that alleles for the same characteristic separate during meiosis.
e.	is negated by the phenomenon of epistasis.

22.

If all the offspring of a cross had the genotype Aa Bb, the parents of the cross would most likely be

a.	AA BB x aa bb.
b.	AA bb x aa BB.
c.	Aa Bb x Aa Bb.
d.	Aa bb x aa Bb.
e.	AA BB x aa bb or AA bb x aa BB.

23.

What fraction of the time will the cross of Aa Bb Cc with Aa Bb Cc produce an offspring that expresses the phenotype represented by the dominant gene C (aa bb C__)?

a.	1/32
b.	3/64
c.	1/16
d.	9/64
e.	27/64

24.

The chance of producing an offspring of genotype Aa BB cc from a cross of Aa Bb Cc with Aa Bb Cc is

a.	1/64.
b.	1/32.
c.	3/64.
d.	1/16.
e.	3/32.

25.

Mendel's dihybrid crosses, but not his monohybrid crosses, showed that

a.	some genes were linked together.
b.	the two alleles controlling a trait were divided equally among the gametes.
c.	alleles for different traits were inherited independently.
d.	one of the pair of alleles is dominant to the other.
e.	the crossing of two different homozygous forms will not produce any offspring in the first generation that will look like either of the parents.

26.

Mendel's dihybrid crosses provided indirect evidence for all but which one of the following?

a.	independent assortment
b.	dominance
c.	linkage
d.	presence of two factors in parents and offspring
e.	segregation of factors

27.

An incompletely dominant gene controls the color of chickens so that BB produces black, Bb produces a slate-gray color called blue, and bb produces splashed white. A second gene controls comb shape, with the dominant gene R producing a rose comb and r producing a single comb. If a pure-breeding black chicken with a rose comb is mated to a splashed white chicken with a single comb in the F₂ generation, what fraction of the offspring will be blue with rose comb?

a.	9/16
b.	3/8
c.	3/16
d.	1/8
e.	1/16

28.

If red (RR) is crossed with white (rr) and produces a pink flower (Rr), and tall (D) is dominant to dwarf (d), the F₂ phenotypic ratio from a cross of RR dd with rr DD would be

a.	9:3:3:1.
b.	1:1:1:1.
c.	1:2:2:4:1:2:1:2:1.
d.	3:6:3:1:2:1.
e.	none of these

29.

The type of inheritance that would suggest the concept of blending is

a.	multiple alleles.
b.	autosomal dominance.
c.	codominance.
d.	incomplete dominance.
e.	codominance and incomplete dominance.

30.

In radishes, red and white are the pure-breeding colors and long and round are the pure-breeding shapes, while the hybrids are purple and oval. The F₂ generation of a cross between long and white and red and round will produce

a.	offspring that will all express dominant traits.
b.	offspring that will all be phenotypically identical.
c.	offspring that will all be genotypically identical.
d.	purple round, purple long, white oval, and red oval offspring in equal numbers, as well as other phenotypes.
e.	offspring that will all be phenotypically and genotypically identical.

31.

In incomplete dominance,

a.	one allele is not dominant to another allele.
b.	the genotype can be determined by the phenotype.
c.	the heterozygote is somewhat intermediate to the two homozygotes.
d.	the intermediate phenotype may be the result of enzyme insufficiency.
e.	all of these

32.

If a child has an AB blood type, the parents

a.	must both have different blood types.
b.	must be A and B, but not AB.
c.	must both be AB.
d.	can be any blood type.
e.	can have different blood types, but neither can be blood type O.

33.

Blood types (A, B, and O) are controlled by

a.	sex-linked genes.
b.	linked genes.
c.	incompletely dominant genes.
d.	multiple alleles.
e.	none of these

34.

The number of different alleles for ABO blood types in the total human population is

a.	4.
b.	6.
c.	9.
d.	undetermined.
e.	3.

35.

If a woman of blood type A has a child of blood type O, the father may belong to blood type

a.	A, AB, O, but not B.
b.	O only.
c.	A, B, O, but not AB.
d.	any blood type other than type A

36.

A gene that produces multiple effects is called a(n)

a.	multiple allele.
b.	autosome.
c.	epistatic gene.
d.	pleiotropic gene.
e.	incompletely dominant gene.

37.

Multiple effects of a single gene is known as

a.	expressivity.
b.	penetrance.
c.	codominance.
d.	pleiotropy.
e.	multiple alleles.

38.

An F₂ phenotypic ratio of 13:3 is the result of

a.	single recessive epistasis.
b.	double or duplicate recessive epistasis.
c.	single dominant epistasis.
d.	double or duplicate dominant epistasis.
e.	one dominant and one recessive gene epistasis.

39.

An F₂ phenotypic ratio of 9:3:4 is the result of

a.	single recessive epistasis.
b.	double or duplicate recessive epistasis.
c.	single dominant epistasis.
d.	double or duplicate dominant epistasis.
e.	one dominant and one recessive gene epistasis.

40.

The reason for the darker fur on the tail, ears, nose, and legs of a Siamese cat is

a.	incomplete dominance.
b.	the interaction of the environment with gene expression.
c.	quantitative inheritance.
d.	epistasis.
e.	none of these

Problem

41.

In a certain plant, when individuals with blue flowers are crossed with individuals with blue flowers, only blue flowers are produced. Plants with red flowers crossed with plants with red flowers sometimes produce only red flowers, although other times they produce either red or blue flowers. When plants with red flowers are crossed with plants with blue flowers, sometimes only red flowers are produced; other times either red or blue flowers are produced. Which gene is dominant?

42.

In garden peas, one pair of alleles controls the height of the plant and a second pair of alleles controls flower color. The allele for tall (D) is dominant to the allele for dwarf (d), and the allele for purple (P) is dominant to the allele for white (p). A tall plant with purple flowers crossed with a tall plant with white flowers produces 3/8 tall purple, 1/8 tall white, 3/8 dwarf purple, and 1/8 dwarf white. What is the genotype of the parents?

43.

In garden peas, one pair of alleles controls the height of the plant and a second pair of alleles controls flower color. The allele for tall (D) is dominant to the allele for dwarf (d), and the allele for purple (P) is dominant to the allele for white (p). A tall purple crossed with a tall purple produces 3/4 tall purple and 1/4 tall white. What is the genotype of the parents?

44.

Assume that red plants crossed with white plants give rise to pink plants. Explain how to eliminate red plants if you start with two pinks.

45.

In horses there are four alleles at the A locus. Arranged in dominance sequence they are:

A (wild) a^b (bay) a^c (brown) a^d (black)

If you bred several bay mares whose sires were brown to a brown stallion whose sire was black, what type of offspring would be produced, and in what proportion?

46.

Gray is homozygous while blue is a heterozygous form of a semilethal gene. Give the ratio of the offspring produced in the cross of two blues.

47.

In the late 1920s, a mutation occurred in many silver fox farms around the world. The fox farms that sold expensive furs were proud of the quality of their furs, and each advertised that it had the best, purest breed of all the fox farms. The new mutations produced a "platinum" coat pattern that was commercially desirable, so the farms crossed them to get more. The results of their breeding experiments were as follows: (1) silver x silver >>> all silver offspring; (2) silver x platinum >>> equal numbers of silver and platinum; (3) platinum x platinum >>> 2 platinum for each silver offspring. Explain.

48.

In poultry, the genes for rose comb (R) and pea comb (P) produce walnut whenever they occur together (R__ P__); single-combed individuals have the homozygous condition for both genes (rr pp).

(a) Give the F₁ and F₂ phenotypic results of a cross of a pure-breeding rose comb

(RR pp) with a pure-breeding pea comb (rr PP).

(b) Give the phenotypic results of a cross of Rr Pp x rr Pp.

(d) Give the phenotypic results of a cross of Rr pp x rr Pp.

(e) Give the phenotypic results of a cross of Rr Pp x rr pp.

49.

Congenital deafness in humans is due to the homozygous condition of either of the recessive genes d or e, or both of these genes. Both dominant D and E are necessary for normal hearing. Gene D/d affects the middle ear, while gene E/e affects the inner ear. It does not matter how good the normal inner ear (as indicated by E__) is; if there is something wrong in the middle ear, the individual is unable to hear. The same applies for the other gene. Give the phenotypic results of the following crosses:

(a) Dd EE x Dd EE

(b) Dd Ee x Dd Ee

(d) Dd EE x Dd ee

(e) Dd EE x DD Ee

50.

White fruit color in summer squash is influenced by a dominant allele W, whereas colored fruit must be ww. In the presence of ww, a dominant gene G results in yellow fruit, and if the individual had both recessive genes in the homozygous condition, it would be green. Give the F₂ phenotypic ratios resulting from a cross of a pure-breeding white of genotype WW GG with a green.

51.

In cultivated stocks, the cross of a variety of white flower plants produced all red flowers in the F₁ generation, but the F₂ generation produced 87 red, 31 cream, and 39 white. Explain these results by giving the genotypes possible for each phenotype.

52.

In summer squash, spherical-shaped fruit has been shown to be dominant to elongated fruit. On one occasion two different spherical varieties were crossed and produced all disk-shaped fruits. When these hybrid disk-shaped fruits were crossed they produced 75 disk-shaped fruits, 48 spherical fruits, and 9 elongated fruits. Explain these results.

53.

In sweet peas, genes C and P are necessary for colored flowers. In the absence of either (__ pp or cc __) or both (cc pp), the flowers are white. Give the probable genotype of a plant with colored flowers and a plant with white flowers that produced 38 plants with colored flowers and 42 plants with white flowers.

54.

In a certain variety of plants a cross between a red-flowered plant and a white-flowered plant produced an all-red flower F₁. In the F₂ there were 140 red, 50 cream, and 65 white.

(a) Offer an explanation for this F₂ ratio.

(b) What ratio would be produced in a testcross of the F₁ hybrid?

55.

In mice the allele for colored fur (C) is dominant to the allele for albinism (c). The allele (W) for normal behavior is dominant to that for waltzing movement (w). Give the probable genotypes of the parents if they produced the offspring listed after the following crosses:

(a)	Colored normal x white waltzer produced 10 colored normal, 8 colored waltzers, 2 white waltzers, 11 white normal.
(b)	Colored normal x white normal produced 35 colored normal, 13 colored waltzers.
(c)	Colored normal x colored normal produced 37 colored normal, 14 colored waltzers, 9 white normal, and 5 white waltzers.