quiz 10
How many copies of a gene for each character does a diploid organism have? Will the alleles be the same at each gene or can they be different? If the alleles are the same, the individual is _______________ at that gene. If the alleles are different, the individual is _________________ at that gene.
2 They can be different. homozygous heterozygous
(allele for purple flowers --------------- - ----- --------------- - ----- allele for white flowers) Each chromosome in this homologous pair possesses a different allele for flower color. Which statement about this homologous pair of chromosomes is correct? A) These homologous chromosomes represent a maternal and a paternal chromosome. B) Each of these homologous chromosomes consists of a single chromatid. Therefore, they must come from a haploid cell. C) These homologous chromosomes are formed by DNA replication.
A
A plant that is true-breeding for a particular trait would: A) be homozygous for that trait. B) show different traits in the F1 generation when crossed with itself. C) be heterozygous for that trait. D) carry two different alleles for that trait.
A
An individual who is heterozygous for gene R (Rr) produces two types of gametes in regard to these alleles: R and r. This illustrates: A) Mendel's Law of Segregation B) Mendel's Law of Independent Assortment C) Both the Laws of Segregation and the Law of Independent Assortment. D) The alignment of nonhomologous pairs of chromosomes during Metaphase I
A
Fur color in Labrador retrievers is determined by two genes (gene B for coat color and gene E for deposition of pigment). Nose, lip and gum color is determined only by gene B. A yellow female with brown nose and gums is mated with a brown (chocolate) male whose mother was yellow. What are their possible offspring? A) ½ yellow and ½ brown - all with brown noses. B) ½ yellow and ½ brown - all with black noses. C) 1/3 yellow and 1/3 black and 1/3 brown - all with black noses. D) ½ brown with brown noses and ½ black with black noses.
A
If the P generation is AABBCC x aabbcc, what is the probability of getting an offspring with genotype AaBbcc in the F2 generation? A) 1/16 B) 1/8 C) 3/16 D) 1/64
A
In a cross of two F1-hybrid plants with purple flowers and round seeds (PpRr), what fraction of the offspring should have purple flowers and round seeds (purple flowers and round seeds are the dominant traits)? A) 9/16 B) 1/12 C) 1/16 D) 3/16 E) 12/16
A
In pea plants, the allele for tall stalks (T) is dominant over the allele for short stalks (t). Suppose a cross between a tall pea plant and a short pea plant produces 43 tall offspring and 47 short offspring. If one of the tall offspring is crossed with one of the short offspring, what ratio of genotypes would be most likely in their offspring? A) 1 Tt : 1 tt B) 1 TT : 2 Tt : 1 tt C) All Tt D) 3 Tt : 1 tt
A
To determine if a plant with purple flowers is homozygous (PP) or heterozygous (Pp) for that trait, one would do a test cross with plants of the ________ genotype. A) pp B) PP C) Pp D) P E) p
A
Based on this pedigree describing the inheritance of an autosomal-dominant disease, what is the probability that person A will birth an affected child if she mates with a wild-type male. A) 25% B) 50% C) 75% D) 100%
B
How many different gamete types can an individual with genotype aaBBCcDd make? A) 2 B) 4 C) 8 D) 16
B
In fruit flies (Drosophila), an autosomal gene controls body color. Individuals that are homozygous recessive have an ebony body color but are quite weak. Individuals that are homozygous dominant have a normal body color and normal physical condition and heterozygous individuals have a normal body color with increased physical condition. This is an example of A) epistasis. B) heterozygote advantage. C) polygenic inheritance. D) multiple alleles.
B
Two F1-hybrid plants with yellow, round seeds (YyRr) are crossed. What is the probability of getting an offspring with the genotype YYRr? A) 4/8 B) 1/8 C) 1/16 D) 2/8 E) 3/16
B
______________ is an example of a character that is controlled by more than one gene (a quantitative character) and demonstrates a continuum of phenotypes. A) Pleiotropy B) Polygenic inheritance C) Epistasis D) Codominance E) Incomplete dominance
B
The black chicken and the white roster are parents to the individuals in the middle image. What type of dominance relationship most likely leads to these feather colors in chickens? A) Complete dominance B) Incomplete dominance C) Codominance D) Pleiotropy
B incomplete spotted codominance pink
Which of the following genotype(s) would result in an individual with the type A blood phenotype? Select all that apply. A) ii B) IAi C) IAIA D) IAIB
B & C
A couple are each carriers for sickle cell disease (a recessive condition). What is the probability that this couple will have 2 children with sickle cell and one child without the disease? A) 1/64 B) 3/64 C) 9/64 D) 1/4
C
A friend wants to have four children. What is the probability that she will have 3 girls and 1 boy? A) 1/16 B) 1/8 C) 4/16 D) 1/2
C
A gene that affects the expression of a second gene is an example of __________________. A) pleiotropy B) codominance C) epistasis D) polygenic inheritance E) incomplete dominance
C
A plant with purple flowers and round seeds (PpRr) is crossed with a plant with white flowers and wrinkled seeds (pprr). What fraction of the offspring should have white flowers and wrinkled seeds? (Purple flowers and round seeds are dominant.) A) 1/5 B) 3/4 C) 1/4 D) 1/3 E) 1/2
C
If a person with blood type A and a person with blood type B have a child, what are the possible blood types that child could have? A) Only type AB is possible B) Types A and B are possible C) Types A, B, AB, and O are possible D) Types A, B, and AB are possible
C
If one parent who has Huntington's disease is heterozygous for the trait and the other parent is not affected, what are the chances of their offspring inheriting the trait? A) 0% B) 25% C) 50% D) 75%
C
In squash, color is determined by two genes that are epistatic. At the first gene, white squash (W) is dominant to colored squash (w). At the second gene, yellow (Y) is dominant to green (y). A squash that is green must have the genotype: A) WWyy B) Wwyy C) wwyy D) A green squash can be either Wwyy or WWyy
C
Suppose a white-furred rabbit breeds with a black-furred rabbit and all of their offspring have a phenotype of gray fur. What does the gene for fur color in rabbits appear to be an example of? A) Codominance B) Epistasis C) incomplete dominance D) Complete dominance
C
The fruit fly Drosophila melanogaster has 3 pairs of autosomal chromosomes and a pair of sex chromosomes. How many different chromosome combinations are produced by independent assortment in D. melanogaster? A) 3 B) 4 C) 8 D) 16
C
Which meiotic process results in the Law of Independent Assortment? A) Homologous chromosomes separating during meiosis I. B) An individual that is heterozygous for a gene producing two different gamete types for that gene. C) Non-homologous chromosomes segregating into daughter cells independently of each other. D) Homologous chromosomes segregating into daughter cells independently of each other.
C
Ana has cystic fibrosis (a recessive condition). Her brother Frank does not have the disease nor do either of their parents. What is the probability that Frank is a carrier for cystic fibrosis? A) 1/4 B) 1/3 C) 1/2 D) 2/3
D
In Labrador retrievers, the allele for black coat color (B) is dominant to the allele for brown coat color (b). However, if a lab has two copies of the recessive allele for a pigment-depositing gene (e), it can only have yellow coat color. In a cross of two doubly heterozygous black labs (BbEe x BbEe), what fraction of the next generation would one expect to be yellow? A) 3/16 B) 1/8 C) 1/16 D) 1/4
D
In a cross of AaBb x AaBb, what fraction of the offspring can be expected to express one of the two dominant alleles, but not both? A) 1/2 B) 3/16 C) 9/16 D) 3/8
D
Skin color in a certain species of fish is inherited via a single gene with four different alleles. One fish of this type has alleles 1 and 3 (S1S3) and its mate has alleles 2 and 4 (S2S4). If each allele confers a unit of color darkness such that S1 has one unit, S2 has two units, and so on, then what proportion of their offspring would be expected to have five units of color? A) 0 B) 1/8 C) 1/4 D) 1/2
D
Suppose that in barley plants, the allele for tall stalks is dominant over short stalks and the allele for wide leaves is dominant over thin leaves. What would be the best way to determine the genotype of a barley plant with a tall stalk and wide leaves? A) Perform a testcross with a known heterozygous barley plant B) Perform a testcross with a barley plant that has a tall stalk and wide leaves C) Perform a testcross with a barley plant that has a tall stalk and thin leaves D) Perform a testcross with a barley plant that has a short stalk and thin leaves
D
The brown allele for eye color (B) is completely dominant over the blue allele for eye color (b). If two brown-eyed parents produce a child that is blue-eyed, what is the probability that at least one out of the next two children they produce will also have blue eyes? A) 12.5% B) 50% C) 25% D) 44%
D
The following question refers to the pedigree chart in the figure below for a family, some of whose members exhibit the dominant trait, W. Affected individuals are indicated by a dark square or circle. What is the probability that individual III-1 is Ww? A) 1/4 B) 1/2 C) 3/4 D) 1
D
This pedigree shows the inheritance of a genetic trait in a family. What is the probability of the affected individual in Generation III having a child who is also affected with this disorder if they marry an unaffected individual who is not a carrier? A) 75% B) 50% C) 25% D) 0%
D
You are given two plants. One plant is tall and the other is short. You cross these parental plants and find all F1 progeny are tall. You cross the F1 progeny with one another and find the resulting F2 generation is composed of 770 tall plants and 300 short plants. You should conclude that ___________. A) both parental plants are homozygous, and short is dominant to tall B) both parental plants are heterozygous, and short is dominant to tall C) you can't tell from the information given D) the F1 plants are heterozygous, and tall is dominant to short E) the F1 plants are homozygous, and tall is dominant to short
D
You cross two true-breeding parents (one with yellow seeds and one with green seeds), grow and self-pollinate the F1 generation, and then count the number of offspring with yellow and green seeds in the F2 generation. If you counted 2,000 F2 offspring and there was a 3:1 ratio of yellow:green seeds, how many offspring would have yellow seeds? A) 500 B) 667 C) 1000 D) 1500 E) 1999
D
You have a pea plant that exhibits the dominant trait of green pods. You cross this plant to a true-breeding plant with the recessive trait of yellow pods. Half of the offspring from this cross have green pods and the other half have yellow pods. Which of the following statements is true? A) The parent with green pods was true-breeding for green pods. B) The parent with yellow pods was heterozygous for this character. C) The parent with green pods had the genotype GG. D) The parent with green pods had the genotype Gg. E) The parent with yellow pods had the genotype Gg.
D
______________________ is a human genetic disease that results in cognitive impairment, but it can be prevented by following a strict low-protein diet. A) Cystic fibrosis B) Sickle-cell anemia C) Huntington's disease D) Phenylketonuria
D
Does this pedigree show a dominant or recessive disorder?
Dominant
C B I I b I I A X X D This image shows a pair of chromosomes. Answer the following questions based on this image. Use each answer only once. The arrow at letter "A" is pointing to The letter B refers to The letter "B" and "b" refer to The arrows at letter "C" are pointing to The arrows at letter "D" are pointing to These chromosomes are
a centromere a gene alleles of gene B sister chromatids a homologous pair of chromosomes in the replicated state
