Bio. Ch. 14 and 15 Mastering
In pea plants, the tall phenotype is dominant to the dwarf phenotype. If a heterozygous pea plant is crossed with a homozygous tall pea plant, what is the probability that the offspring will be dwarf in size?
0
A man has extra digits (six fingers on each hand and six toes on each foot). His wife and their daughter have the normal number of digits (five fingers on each hand and five toes on each foot.) Having extra digits is a dominant trait. The couple's second child has extra digits. What is the probability that their next (third) child will have extra digits?
1/2
A man has six fingers on each hand and six toes on each foot. His wife and their daughter have the normal number of digits. Remember that extra digits is a dominant trait. What fraction of this couple's children would be expected to have extra digits?
1/2
A recessive allele on the X chromosome is responsible for red-green color blindness in humans. A woman with normal vision whose father is color blind marries a color-blind male. What is the probability that this couple's first son will be color blind?
1/2
Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails (t). What fraction of the progeny of crosses BbTt × BBtt will be expected to have black fur and long tails?
1/2
Albinism is a recessive trait. A man and woman both show normal pigmentation, but both have one parent who has albinism (without melanin pigmentation). What is the probability that their first child will have albinism?
1/4
White eye color is a sex-linked, recessive characteristic in fruit flies. If a female having white eyes is crossed with a wild-type male, what percentage of the F1 males will have white eyes?
100%
When Mendel crossed yellow-seeded and green-seeded pea plants, all the offspring were yellow-seeded. When he took these F1 yellow-seeded plants and crossed them to green-seeded plants, what genotypic ratio was expected?
1:1
Two true-breeding stocks of pea plants are crossed. One parent has red, axial flowers, and the other has white, terminal flowers; all F1 individuals have red, axial flowers. The genes for flower color and location assort independently. Among the F2 offspring, what is the probability of producing plants with white axial flowers?
3/16
In humans, ABO blood types refer to glycoproteins in the membranes of red blood cells. There are three alleles for this autosomal gene: IA, IB, and i. The IA allele codes for the A glycoprotein, The IB allele codes for the B glycoprotein, and the i allele doesn't code for any membrane glycoprotein. IA and IB are codominant, and i is recessive to both IA and IB. People with type A blood have the genotypes IAIA or IAi, people with type B blood are IBIB or IBi, people with type AB blood are IAIB, and people with type O blood are ii. If a woman with type AB blood marries a man with type O blood, which of the following blood types could their children possibly have?
A and B
Which of the following statements is correct in describing the terms monohybrid cross and dihybrid cross?
A dihybrid cross involves organisms that are heterozygous for two characters that are being studied, and a monohybrid cross involves organisms that are heterozygous for only one character being studied
Generally, only female cats have the tortoiseshell phenotype for fur color. Which of the following statements explains this phenomenon?
A male inherits only one allele of the X-linked gene controlling hair color
If a diploid cell undergoes meiosis and produces two gametes with n + 1 chromosomes and two gametes with n− 1 chromosomes, what type of error occurred?
A nondisjunction error occurred in meiosis I, in which both members of a homologous pair migrated to the same pole of the cell
If a diploid cell undergoes meiosis and produces two gametes that are normal, and one with n − 1 chromosomes, and one with n + 1 chromosomes, what type of error occurred?
A nondisjunction error occurred in meiosis II, in which both sister chromatids of a chromosome migrated to the same pole of the cell.
What kind of cell results when a diploid and a haploid gamete fuse during fertilization?
A triploid cell
A black guinea pig crossed with a guinea pig with albinism produced 12 black offspring. When the albino was crossed with a second black animal, six blacks and six albinos were obtained. What is the best explanation for this genetic situation?
Albinism is a recessive trait; black is a dominant trait
Which of the following individuals will inherit an X-linked allele from a man who carries it?
All of his daughters
Which of the following statements correctly explains the fact that all seven of the pea plant traits studied by Mendel obeyed the principle of independent assortment?
All of the genes controlling the traits behaved as if they were on different chromosomes
What is a nondisjunction?
An error in cell division that causes homologous chromosomes or sister chromatids to move to the same side of the dividing cell
In human blood types, Rh positive is a trait that shows simple dominance over Rh negative. A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Which of the following phenotypes is possible for the father?
B positive
Gray seed color in peas is dominant to white. Assume that Mendel conducted a series of experiments where plants with gray seeds were crossed among themselves, and the following progeny were produced: 302 gray and 98 white. What is the most probable genotype of each parent?
Gg × Gg
A man with type A blood marries a woman with type B blood. Their child has type O blood. What is the genotype of the man?
I ^A i
A man with type A blood marries a woman with type B blood. Their child has type O blood. What is the genotype of the woman?
I ^B i
When can nondisjunction occur?
In mitosis, when sister chromatids fail to separateIn meiosis, when homologous chromosomes fail to separateIn meiosis, when sister chromatids fail to separate
Which of the following scenarios describes an example of epistasis?
In rabbits and many other mammals, one genotype (ee) prevents any fur color from developing
Marfan syndrome in humans is caused by an abnormality of the connective tissue protein fibrillin. Patients are usually very tall and thin, with long spindly fingers, curvature of the spine, sometimes weakened arterial walls, and sometimes eye problems, such as lens dislocation. Which of the following would you conclude about Marfan syndrome from this information?
It is pleiotropic
Why are males more often affected by sex-linked traits than females?
Males are hemizygous for the X chromosome
Which of the following statements is a correct explanation for the observation that all offspring exhibit a phenotype for a particular trait that appears to be a blend of the two parental varieties?
Neither of the parental genes is dominant over the other
Why did all of the F1 offspring of Mendel's classic pea cross always look like one of the two parental varieties?
One allele was dominant
One of two major forms of a human condition called neurofibromatosis (NF 1) is inherited as a dominant gene, although it may range from mildly to very severely expressed. Which of the following is the best explanation for why a young, affected child is the first in her family to be diagnosed?
One of the parents has a mild expression of the gene
Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human X chromosome. The patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. They rarely live past their 20s. How likely is it for a woman to have this condition?
One-half of the daughters of an affected father and a carrier mother could have this condition
Which of the following statements regarding gene linkage is correct?
The closer two genes are on a chromosome, the lower the probability that a crossover will occur between them
Mendel crossed yellow-seeded and green-seeded pea plants and then allowed the offspring to self-pollinate to produce an F2 generation. The results were as follows: 6,022 yellow and 2,001 green (8,023 total). Which of the following statements correctly describes the relationship of the allele for green seeds to the allele for yellow seeds?
The green allele is recessive to the yellow allele
Which of the following statements about independent assortment or segregation is correct?
The law of independent assortment describes the behavior of two or more genes relative to one another
What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants?
Traits are inherited in discrete units and are not the result of "blending"
Which of the following statements correctly describes how Mendel accounted for the observation that traits had disappeared in the F1 generation and then reappeared in the F2 generation?
Traits can be dominant or recessive, and the recessive traits were "hidden" by the dominant ones in the F1
Of the following chromosomal abnormalities, which type is most likely to be viable in humans?
Trisomy
Which of the following is an example of monosomy in humans?
Turner Syndrome
Which syndrome is characterized by the XO chromosome abnormality?
Turner syndrome
Consider the following family history: Bob has a genetic condition that affects his skin. Bob's wife, Eleanor, has normal skin. No one in Eleanor's family has ever had the skin condition. Bob and Eleanor have a large family. Of their eleven children, all six of their sons have normal skin, but all five of their daughters have the same skin condition as Bob. Based on Bob and Eleanor's family history, what inheritance pattern does the skin condition most likely follow?
X-linked dominant
Red-green color blindness is a sex-linked recessive trait in humans. Two people with normal color vision have a color-blind son. What are the genotypes of the parents?
X^N X^n and X^N Y
The SRY gene is best described as ________
a gene present on the Y chromosome that triggers male development
Mendel's observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division?
anaphase I of meiosis
Hydrangea plants of the same genotype are planted in a large flower garden. Some of the plants produce blue flowers and others pink flowers. This can be best explained by which of the following?
environmental factors such as soil pH affect the phenotype
Gene S controls the sharpness of spines in a type of cactus. Cacti with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cacti have dull spines. At the same time, a second gene, N, determines whether or not cacti have spines. Homozygous recessive nn cacti have no spines at all. The relationship between genes S and N is an example of which of the following inheritance patterns?
epistasis
A man with type A blood marries a woman with type B blood. Their child has type O blood. What is the genotype of the child?
ii
A man with type A blood marries a woman with type B blood. Their child has type O blood. What genotypes would you expect in future offspring from this marriage?
ii, I ^A i, I ^B i, I ^A I^B
Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The flower color trait in radishes is an example of which of the following inheritance patterns?
incomplete dominance
Mendel continued some of his experiments into the F2 or F3 generation in order to ________
observe whether or not a recessive trait would reappear
Which of the following inheritance patterns describes the ability of a single allele to have multiple phenotypic effects?
pleiotropy
Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The part of the radish we eat may be oval or long, with long being the dominant trait. If true-breeding red long radishes are crossed with true-breeding white oval radishes, the F1 will be expected to exhibit which of the following phenotypes?
purple and long
In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (CRCW) offspring of red (CRCR) and white (CWCW) homozygotes. Which of the following crosses would produce offspring in the ratio of 1 red:2 roan:1 white?
roan × roan
Which of the following phenotypes is an example of polygenic inheritance?
skin pigmentation in humans
In cats, black fur color is determined by an X-linked allele; the other allele at this locus determines orange color. The heterozygote is tortoiseshell. What kinds of offspring would you expect from the cross of a black female and an orange male?
tortoiseshell females; black males
One possible result of chromosomal breakage is for a fragment to join a nonhomologous chromosome. What is this type of chromosomal alteration called?
translocation
Albinism is a recessive trait. A man and woman who both have normal pigmentation have one child out of three who has albinism (without melanin pigmentation). What are the genotypes of this child's parents?
Both parents must be heterozygous
