Unit 4 Review - Genetics

Each parent contributes one of the genes for a particular trait. The genes of the pair are called:
1. variables
2. hybrids
3. alleles
4. gametes
Tay Sachs disease is a fatal genetic disorder. Children born with this disorder generally die before they are five years old. A couple has had three children who died of Tay Sachs. About this couple it can safely be assumed that:
1. they are both homozygous for the Tay Sachs trait
2. they are both heterozygous for the Tay Sachs trait
3. one is heterozygous and the other is homozygous for the Tay Sachs trait
4. any children they have in the future will also die from this disease
When two bell shaped squash are crossed, 25% of the offspring are round, 25% are oblong, and 50% are in between, or bell shaped. This cross illustrates:
1. a pedigree
2. mutiple alleles
3. codominance
4. a recessive trait
Traits that are influenced by at least several genes and also the environment are known as:
1. variations
2. multifactorial
3. dominant
4. recessive
In humans, the child’s sex is determined by:
1. the father
2. the mother
3. both parents equally
4. an autosome
The observable traits of an organism are known as its
1. allele
2. dominance
3. phenotype
4. genotype
The gene makeup of an organism for a particular trait is known as its
1. allele
2. dominance
3. phenotype
4. genotype
The genotypes that cannot be determined from the inspection of the offspring of a cross are the:
1. homozygous dominant and the homozygous recessive
2. codominant
3. codominant and the homozygous recessive
4. homozygous dominant and the heterozygous dominant
Chromosomes that carry genes that code for the same products, such as hemoglobin or eye pigment, are said to be:
1. homozygous
2. homologous
3. heterozygous
4. heterogeneous
Mendel discovered principles of inheritance because he:
1. observed simultaneously all of the characteristics in which the parents differed
2. was smarter than any other scientist of his time
3. ignored all characteristics except a few markedly contrasting ones which he studied carefully
4. studied only the offspring obtained from a single mating
The color black is dominant in guinea pigs. The phenotypes of homozygous black guinea pigs and heterozygous black guinea pigs are:
1. BB and Bb
2. black
3. white
4. gray
In snapdragons, Tallness (T) is dominant to dwarfness (t). In a cross between two plants that are heterozygous for this trait, the percent of offspring expected to exhibit dwarfness is
1. 0%
2. 25%
3. 50%
4. 75%
5. 100%
In snapdragons, Tallness (T) is dominant to dwarfness (t). In a cross between two plants that are homozygous for the recessive allele, the percent of offspring expected to exhibit tallness is
1. 0%
2. 25%
3. 50%
4. 75%
5. 100%
In snapdragons red flower color is due to gene (R) and white to its allele (r). The heterozygous condition results in pink (Rr) flower color. In a cross between two pink snapdragons, what percentage of the offspring can be expected to be pink?
1. 0%
2. 25%
3. 50%
4. 75%
5. 100%
In snapdragons red flower color is due to gene (R) and white to its allele (r). The heterozygous condition results in pink (Rr) flower color. In a cross between two pink snapdragons, what percentage of the offspring can be expected to be red?
1. 0%
2. 25%
3. 50%
4. 75%
5. 100%
In pea plants, the allele for green pods (G) is dominant and the allele for yellow pods (g) is recessive. A researcher crosses two green pea plants, and the in F₁ generation, 25% of the offspring exhibit yellow pods. What are the genotypes of the parents?
1. Gg and Gg
2. GG and Gg
3. Gg and gg
4. gg and GG
In pea plants, the allele for green pods (G) is dominant and the allele for yellow pods (g) is recessive. A researcher crosses two green pea plants, and the in F₁ generation, all of the offspring exhibit green pods. Can you determine the genotypes of both parents
1. Yes, they are GG and GG
2. Yes, they are Gg and GG
3. Yes, they are gg and gg
4. No, they could be Gg and Gg OR GG and Gg
5. No, they could be Gg and GG OR GG and GG
Cystic Fibrosis (CF) is a genetic disorder that is controlled by a recessive allele. If a person suffering from CF were to marry an individual who is heterozygous for the trait, what % of their children could be expected to suffer from the disease? Ignore issues of sterility in persons with CF.
1. 0%
2. 25%
3. 50%
4. 75%
5. 100%
Cystic Fibrosis (CF) is a genetic disorder that is controlled by a recessive allele. If a person suffering from CF were to marry an individual who is heterozygous for the trait, what % of their children could be expected to unaffected carriers of the trait? Ignore issues of sterility in persons with CF.
1. 0%
2. 25%
3. 50%
4. 75%
5. 100%
In dragons, large scales (S) are dominant and small scales (s) are recessive. A dragon that is heterozygous for the trait is crossed with a dragon that has small scales. What should be the ratio of large-scaled dragons to small-scaled dragons among the offspring?
1. 1:1
2. 2:1
3. 1:2
4. 3:1
5. 1:3
In all conditions in which a defective gene is on the X chromosome, transmission to a male can be:
1. only from his mother
2. only from his father
3. either from his father or his mother
4. from neither his mother nor father
What bloodtype could not be found in the offspring of a couple, each of whom has type AB blood?
1. Type O
2. Type A
3. Type AB
4. Type B
Three babies were recently mixed up in a hospital. The blood types of the possible parents and babies are shown below.
Parents
#1 Parents
#2 Parents
#3 Baby
#1 Baby
#2 Baby
#3
A and B A and A AB and O B O AB

Who are the possible parents of baby #1?
1. Parents #1
2. Parents #2
3. Parents #3
Three babies were recently mixed up in a hospital. The blood types of the possible parents and babies are shown below.
Parents
#1 Parents
#2 Parents
#3 Baby
#1 Baby
#2 Baby
#3
A and B A and A AB and O B O AB

Who are the possible parents of baby #3?
1. Parents #1
2. Parents #2
3. Parents #3
Three babies were recently mixed up in a hospital. The blood types of the possible parents and babies are shown below.
Parents
#1 Parents
#2 Parents
#3 Baby
#1 Baby
#2 Baby
#3
A and B A and A AB and O B O AB

Who could not have been the parents of baby #2?
1. Parents #1
2. Parents #2
3. Parents #3
The term "sex-linked trait" almost universally refers to alleles with genes on the
1. Y chromosome
2. X chromosomes
3. 22 autosomes
Colorblindness is a sex-linked trait that is uncommon in women because
1. it is carried by a gene on the Y chromosome
2. women have to receive the trait from both parents in order for it to be expressed
3. women have a different gene for color vision
The image below is a partial pedigree for the inheritence of hemophilia in the royal families of Europe.

Based upon this pedigree, hemophilia is
1. sex-linked
2. autosomal recessive
3. autosomal dominant
4. autosomal codominant
A man with type A blood marries a woman with type B blood. Their three children have blood types A, B and O, respectively. What are the parental genotypes?
1. Father: AO || Mother: BO
2. Father: AO || Mother: BB
3. Father: AA || Mother: BO
4. Father: AA || Mother: BB
Both A and B blood type alleles are dominant to type O. To what do we owe the high frequency of people in the population with type O blood?
1. O is the most common allele
2. Many people have genetic diseases
3. Women are more likely to have type O blood
4. Babies with types A and B are more likely to die in childhood
Colorblindness is a recessive, X-linked trait. In marriages between a man who is colorblind, and a woman who is a carrier, what percentage of the children can be expected to be sons who are color blind?
1. 0%
2. 25%
3. 50%
4. 75%
5. 100%
Colorblindness is a recessive, X-linked trait. In marriages between a man who is colorblind, and a woman who is a carrier, what percentage of the children can be expected to be sons who are not color blind?
1. 0%
2. 25%
3. 50%
4. 75%
5. 100%
Colorblindness is a recessive, X-linked trait. In marriages between a man who is colorblind, and a woman who is a carrier, what percentage of the children can be expected to be daughters who are color blind?
1. 0%
2. 25%
3. 50%
4. 75%
5. 100%
Colorblindness is a recessive, X-linked trait. In marriages between a man who is colorblind, and a woman who is a carrier, what percentage of the children can be expected to be daughters who are carriers of the trait?
1. 0%
2. 25%
3. 50%
4. 75%
5. 100%
Colorblindness is a recessive, X-linked trait. In marriages between a man who is colorblind, and a woman who is a carrier, what percentage of the children can be expected to be daughters who do not carry the trait at all?
1. 0%
2. 25%
3. 50%
4. 75%
5. 100%
A father is heterozygous for a particular autosomal dominant trait. If his spouse is homozygous recessive for the same trait, what percentage of their offspring can be expected to express the dominant condition?
1. 0%
2. 25%
3. 50%
4. 75%
5. 100%
The pedigree above indicates that the trait in question is
1. sex-linked
2. autosomal recessive
3. autosomal dominant
In snapdragons, tallness (T) is dominant to dwarfness (t), while red flower color is due to gene (R) and white to its allele (r). The heterozygous condition results in pink (Rr) flower color. A dwarf red snapdragon is crossed with a plant homozygous for tallness and white flowers. What percentage of the offspring can be expected to have the tall, pink-flowered phenotype>
1. 0%
2. 25%
3. 50%
4. 75%
5. 100%

Parents #1	Parents #2	Parents #3	Baby #1	Baby #2	Baby #3
A and B	A and A	AB and O	B	O	AB