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| 1 | |
From a cross of heterozygotes, which of the following ratios show co-dominance? |
| | A) | 2:1 |
| | B) | 3:1 |
| | C) | 1:2:1 |
| | D) | 1:1 |
| | E) | 4:1 |
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| 2 | |
From a cross of heterozygotes, which of the following monohybrid ratios describes complete dominance? |
| | A) | 2:1 |
| | B) | 3:1 |
| | C) | 1:3 |
| | D) | 1:2:1 |
| | E) | 4:1 |
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| 3 | |
_______________ is the masking of one gene's phenotype by another. |
| | A) | penetrance |
| | B) | epistasis |
| | C) | mutation |
| | D) | phenocopy |
| | E) | pleiotropy |
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| 4 | |
A gene present at 1% or greater in the population is: |
| | A) | wild-type |
| | B) | pleiotropic |
| | C) | dominant |
| | D) | co-dominant |
| | E) | recessive |
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| 5 | |
A new phenotype not seen in the parents can arise by: |
| | A) | gene interaction |
| | B) | co-dominance |
| | C) | complementation |
| | D) | none of the above |
| | E) | all of the above |
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| 6 | |
The degree or intensity with which a particular genotype is expressed in a phenotype is its: |
| | A) | dominance |
| | B) | penetrance |
| | C) | pleiotropy |
| | D) | recessiveness |
| | E) | expressivity |
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| 7 | |
A person who has type A blood has:
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| | A) | anti-A antibodies |
| | B) | anti-B antibodies |
| | C) | anti-AB antibodies |
| | D) | both anti-A and -B antibodies |
| | E) | no surface antigens |
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| 8 | |
From a cross of heterozygotes, which of the following ratios indicates a lethal gene?
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| | A) | 2:1 |
| | B) | 3:1 |
| | C) | 1:2:1 |
| | D) | 1:1 |
| | E) | 4:1 |
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| 9 | |
A trait caused by environmental agents that mimic a disease allele's effects can be described as: |
| | A) | pleiotropic |
| | B) | co-dominant |
| | C) | phenocopy |
| | D) | completely dominant |
| | E) | mutant |
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| 10 | |
Height in humans is an example of a ___________ trait.
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| | A) | quantitative |
| | B) | continuous |
| | C) | polygenic |
| | D) | none of the above |
| | E) | all of the above |
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| 11 | |
The genes IA, IB, and i contribute to the ABO blood antigens in humans. In another trait, R (Rh +) is dominant to r (Rh-). If a mother with a phenotype of A/Rh+ has a child with a phenotype of O/Rh+, which one of the possible genotypes is not possible for the father?
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| | A) | IAi rr |
| | B) | IBi RR |
| | C) | ii rr |
| | D) | ii Rr |
| | E) | IAIA RR |
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| 12 | |
If a mother with a phenotype of B/Rh- has a child with a phenotype of O/Rh-, which one of the following genotypes is possible for the father?
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| | A) | IAi rr |
| | B) | IBi RR |
| | C) | IAIB rr |
| | D) | ii RR |
| | E) | IBIB Rr |
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| 13 | |
The genes IA, IB, and i contribute to the ABO blood antigens in humans. In two other traits, R (Rh +) is dominant to r (Rh-) and M and N are codominant alleles. If a mother with the blood type of A Rh+ N has a child of phenotype AB Rh+ MN, which genotype is possible for the father?
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| | A) | IAi rr MN |
| | B) | IBi RR MN |
| | C) | ii rr NN |
| | D) | ii rr MM |
| | E) | none of the above |
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| 14 | |
If a mother with a phenotype of AB Rh- MN has a child with a phenotype A Rh- MM, which genotype is possible for the father?
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| | A) | IAi rr MN |
| | B) | IBi RR MN |
| | C) | ii rr NN |
| | D) | IBIB Rr MM |
| | E) | IAIA RR MN |
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| 15 | |
Coat color in a certain species of animal is governed by multiple alleles. The order of decreasing dominance for these alleles is as follows: black (B), buff, (f), brown (r) and albino (b). What phenotypic ratios are observed from a Bb X rb cross?
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| | A) | 1 black: 1 buff |
| | B) | all black |
| | C) | 2 black: 1 brown: 1 albino |
| | D) | 1 buff: 1 brown |
| | E) | 2 black: 1 buff: 1 brown |
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| 16 | |
In corn three dominant genes are necessary for aleurone color. If any of the three genes are homozygous for the recessive alleles, the corn is colorless. Predict the ratio of colored:colorless phenotypes in the offspring of the cross BbDdRr x BbDdRr.
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| | A) | 9:7 |
| | B) | 27:37 |
| | C) | 15:17 |
| | D) | 23:41 |
| | E) | 13:3 |
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| 17 | |
In rats, the allele for pigment (P) is dominant to no pigment (p) and the allele for black (B) is dominant to the allele for cream (b). If pigment allele (P) is absent, there is no pigment, regardless of which black allele is present, and the rats are cream. How many cream colored rats will be present in the F2 of a cross between a true-breeding black rat and a cream-colored rat that is homozygous for recessive alleles of both genes?
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| | A) | 1 in 16 |
| | B) | 3 in 16 |
| | C) | 4 in 16 |
| | D) | 7 in 16 |
| | E) | 9 in 16 |
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| 18 | |
In the common daisy the genes A and a, B and b represent two pairs of alleles acting on flower color. A and B are both required for color. How many plants with colored flowers will be found in the F2 of a cross between two colorless plants, one homozygous for A and the other homozygous for B?
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| | A) | 1 in 16 |
| | B) | 4 in 16 |
| | C) | 7 in 16 |
| | D) | 9 in 16 |
| | E) | 13 in 16 |
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| 19 | |
In a certain breed of plants, thorns are determined by the dominant gene T and thornless is determined by the recessive gene t. T is 80% penetrant in the heterozygote; 20% of heterozygotes will appear thornless. If you make the parental cross TT x tt; what would be the expected number of phenotypes observed in a population of 500 F2 plants?
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| | A) | 325 thorny: 175 thornless |
| | B) | 100 thorny: 400 thornless |
| | C) | 175 thorny: 325 thornless |
| | D) | 400 thorny: 100 thornless |
| | E) | 25 thorny: 475 thornless |
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| 20 | |
In a certain breed of plants, thorns are determined by the dominant gene T and thornless is determined by the recessive gene t. You know that T is not completely penetrant in the heterozygote, Tt. You cross TT x tt plants, and score 500 individuals in the F2. You obtain data of 225 thorny:275 thornless. How penetrant is thorniness in the heterozygote?
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| | A) | 10% |
| | B) | 24% |
| | C) | 40% |
| | D) | 60% |
| | E) | 75% |
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| 21 | |
Three mutant strains of plant, Michigan, Kansas, and Oregon have white flowers and are true-breeding. In a complementation test, you cross Michigan x Kansas and obtain all white flowers. You cross Oregon with Kansas and obtain all red flowers. Which plants are likely to have a mutation in the same gene?
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| | A) | Oregon and Kansas |
| | B) | Michigan and Kansas |
| | C) | Oregon and Michigan |
| | D) | all have mutations in different genes |
| | E) | all have mutations in the same gene |
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| 22 | |
You are an entomologist working with beetles, and have two true-breeding strains that show no spots. You cross these strains and obtain all spotless beetles in the F1. In the F2, you observe 13 spotless:3 spotted beetles. If you cross random spotted beetles of the F2, what phenotypic ratio do you expect for individual crosses?
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| | A) | 3 spotted: 1 spotless |
| | B) | 1 spotted: 1spotless |
| | C) | all spotted |
| | D) | b & c |
| | E) | a & c |
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| 23 | |
You are a commercial berry farmer with two true-breeding strains, one with red berries and one with white. You cross these strains and obtain all red berries in the F1. In the F2, you observe the ratio of 12 red: 3 golden: 1 white berries. If you cross random individuals bearing white berries with individuals bearing golden berries, what phenotypic ratios do you expect to see in individual crosses?
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| | A) | all white |
| | B) | 1 golden: 1 white |
| | C) | all golden |
| | D) | b & c |
| | E) | e a & b |
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| 24 | |
Fruit flies can have black or tan body color. Black bodies are the result of a mutation in either the black (B) or ebony (E) gene. For both genes, the black body alleles are recessive to the tan body alleles. You have a vial of true-breeding flies with black bodies and decide to do a complementation test to determine the genotype of your flies. You cross your flies to two other black body mutant strains, BBee and bbEE. In both cases, the F1 flies all have black bodies. The genotype of your unknown flies is:
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| | A) | bbee |
| | B) | BBEE |
| | C) | BbEe |
| | D) | BBee |
| | E) | bbEE |
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| 25 | |
Several genes interact to influence mouse coat color. Wild-type AA animals have dark and yellow striped hairs. The AY allele of the same gene is recessive lethal, but is also dominant to the A allele--it gets rid of the dark stripe and thus produces an all yellow color. The B gene controls whether the dark color of a hair stripe is black (B) or brown (b). B is dominant to b. Black and yellow striped hairs are referred to as "agouti". Brown and yellow striped hairs are "cinnamon". If mice of genotype AYABb are crossed to each other, what resulting phenotypic ratios do you see in the next generation among the living mice?
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| | A) | 9:3:3:1 (yellow: agouti: black: brown) |
| | B) | 9:3:4 (yellow: agouti: cinnamon) |
| | C) | 9:7 (yellow: agouti) |
| | D) | 8:3:1 (yellow: agouti: cinnamon) |
| | E) | 12:3:1 (yellow: agouti: cinnamon) |
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