Ch. 11
What is the probability of two successive coin tosses coming up tails?
1/4
If you cross two heterozygous Yy pea plants, what proportion of the offspring will be the dominant color yellow?
75%
The offspring of a monohybrid testcross could have what possible genotype(s)?
AA and Aa
The stability of inheritance and variation between offspring from one generation to the next is explained by the field of
Genetics
During Mendel's pea plants experiment, he discovered that the trait for tallness is dominant to that of shortness. Which of the following statements is correct?
Tall = TT or Tt while short = tt
Mendel bred a plant with a dominant phenotype to an individual with the recessive phenotype. He then analyzed the offspring to determine the unknown genotype. This type of experiment is called a(n)
Testcross
In order to conduct a testcross, one of the parents needs to be true-breeding _______
homozygous recessive
Which parent will pass a recessive X-linked allele to their sons?
mother
If a human who is a tongue roller (T) and has unattached ear lobes (E) marries a person who cannot roll their tongue and has attached earlobes, could they produce an offspring that was also a non-tongue-roller with attached earlobes? What would be the genotype of the first parent? The second parent?
yes; TtEe; ttee
A female is a carrier of a recessive, X-linked trait. She reproduces with an unaffected male. What are the chances that they have an affected female offspring?
0
A certain badger is heterozygous for two genes: he has sharp claws and bad breath. He mates with another badger that is homozygous for both genes, with sharp claws and minty-fresh breath. What are the chances that they have an offspring with sharp claws and minty-fresh breath? (Assume simple, Mendelian inheritance.)
1/2
Achondroplasia is a common form of dwarfism caused by autosomal dominant mutation in the fibroblast growth factor receptor 3 (Fgfr3) gene. If a person with achondroplasia (Aa) married and had children with a person of normal height, what is the probability that both their first child and second child would have achondroplasia?
1/4
What is the probability that two heterozygous individuals will produce a child that is recessive?
1/4
The life cycle of the fruit fly, from fertilized egg to adult, takes approximately how many days?
10 to 14
When predicting the phenotypic ratio of a crossing between two heterozygous corn plants (PpSs), the ratio was shown to be 9:3:3:1. What would the phenotypic ratio be if we crossed two homozygous corn plants, with one homozygous dominant for both color and texture (PPSS) and the other homozygous recessive for both traits (ppss)?
1:0:0:0
In humans the recessive allele "a" results in the lack of the production of the skin pigment melanin. People who are homozygous recessive lack pigment and have white skin, pink eyes, and white hair. This phenotype is referred to as albinism. The normal allele for the gene in the pigment production pathway is "A". What phenotypic ratio of offspring is predicted by a cross between a man who is heterozygous (Aa) and an albino woman?
1:1 Albino: Normal pigment
If a population has two alleles for an X-linked gene, how many different variations of male genotypes are possible?
2
The probability of obtaining a dominant phenotype from self-fertilization of a heterozygous individual is
3/4
Mendel's monohybrid cross of tall parents with the genotype Tt resulted in a tall to short ratio of
3:1
If you cross RrYy and RRyy pea plants, what fraction of the offspring will have yellow peas? R = round, r = wrinkled, Y = yellow, y = green
50%
If a woman is a carrier for the color blind recessive allele and her husband is normal, what are their chances that their son will be color blind?
50% since the mother is a carrier
Which statement about the blending concept of inheritance is correct?
A cross between a tall man and a short woman would always produce children of medium height.
The ability to roll the edges of the tongue upward in a U-shape is considered to be an inherited trait. The standard assumption is that tongue-rolling is a dominant allele at a single gene locus. Which of the following would cast doubt on this assumption? Select all that apply.
A student who can roll his tongue has both a mother and father who cannot.
What is the blending theory of inheritance?
A theory that describes how offspring show traits intermediate between those of the parents.
What is the correct designation for predicting a cross between two heterozygous organisms?
AaBb X AaBb
Some plants fail to produce chlorophyll, and this trait appears to be recessive. Many plants also self-pollinate. If we locate a pea plant that is heterozygous for this trait, self-pollinate it and harvest seeds, what are the likely phenotypes of these seeds when they germinate?
About 1/4 will be white and three-fourths green since it is similar to a monohybrid cross.
What did Morgan think was odd about the results of his experiments with X-linked inheritance and fruit flies?
All of the recessive individuals were males.
Why did Mendel choose pea plants for his research?
All of these were important characteristics in Mendel's selection.
Autosomes
Are chromosomes that are the same for both sexes
Human beings have 23 pairs of chromosomes. Of these, 1 pair determines gender and the other 22 pairs are _______.
Autosomes
An individual who does not express a genetic condition but can pass the condition to their offspring are said to be _______ of the condition.
Carrier
In a Chi Square analysis the ______ is determined by the number of types minus one.
Degrees of freedom
An individual of genotype TtBb bred with an individual of genotype TtBb is an example of a(n)
Dihybrid
Polygenic traits are controlled by two or more sets of alleles which have a quantitative effect on an individual's phenotype, causing the effects to be additive. These are ________ alleles
Dominant
Which of the following is not part of Mendel's law of segregation?
Each gamete will contain two factors for a trait.
In the study of genetics the offspring of the P generation is referred to as the
F1 generation
Which term is currently used to describe the hereditary units described by Mendel's particulate theory of inheritance?
Genes
If the alleles for Huntington disease are represented by the letter "H," which of the following genotypes belongs to individuals affected with this disorder?
HH, Hh
What aspect of Mendel's background gave him the necessary tools to discover the laws of inheritance?
He had studied mathematics and probability.
Which of the following is an autosomal dominant disorder?
Huntington disease
If two parents have blood genotypes IAi and IBi, which of the following blood genotypes are possible in their children?
IAi, IBi, IAIB, and ii
In the experiment determining the parental genotype of fruit flies from a monohybrid cross, if the number of long wing offspring was equal to the number of short wing offspring, what would the parental genotype have been?
Llxll
A phenotype that results from a genetic change and is different from the common phenotype observed in nature is called a
Mutant
In pea plants, smooth (S) peas are dominant over wrinkled (s) peas in the single gene controlling pea texture. A plant with smooth peas is crossed with a plant with wrinkled peas. Of the progeny, 252 are smooth and 247 are wrinkled. What are the genotypes of the parent plants?
Ss and ss
True or false: Homologous chromosomes have the same locus for a particular gene.
True
In a Punnett square, all possible types of sperm are lined up ______.
Vertically
The most commonly found phenotype in the natural population of a species is called the
Wild-type
What is the genotype of the male fruit fly?
XY
Which of the following is the correct genotype for a man who has a recessive X-linked genetic disorder?
XtY
What is the definition of a monohybrid cross?
a mating between individuals that traces a single gene of interest
Alternate forms of a gene are called
alleles
The pedigree chart depicts the inheritance pattern of _____. Circles depict females and squares depict males. Colored shapes represent affected individuals (expressing a trait) and uncolored shapes are unaffected (do not express a trait).
an autosomal recessive characteristic with both parents being heterozygous
Methemoglobinemia is a(n)
autosomal recessive disorder
If two individuals appear normal for a genetic condition, but they produce a child who expresses the condition, the parents would be called ______ for that condition.
carriers
The most common lethal genetic disease among Caucasians is
cystic fibrosis
An experimental cross in which the parents differ in two traits is called a _______ cross.
dihybrid
An allele that exerts its effects whenever it is present is
dominant
If an individual is homozygous for a particular trait
each parent contributed the same allele for that trait
The particular set of alleles an individual receives at fertilization is called its __________.
genotype
Dominant alleles ______
have a DNA sequence that produces a fully functioning protein
Because human males have only one allele for X-linked traits, they are considered ________ for this condition
hemizygous
When Mendel crossed two purple-flowered pea plants with each other, he obtained a phenotypic ratio of 3:1 (purple-flowered pea plants to white-flowered pea plants). His results are consistent with which of the following sets of parents?
heterozygous purple pea plant and heterozygous purple pea plant
A testcross involves an individual with the dominant phenotype but unknown genotype being crossed with an individual that has a(n) ________ genotype.
homozygous recessive
If red flowers are crossed with white flowers and the resulting flowers are all pink, this would be an example of ________ dominance
incomplete
A heterozygote displaying an intermediate variation of a trait—a phenotype in between that of individuals homozygotic for both alleles— is an example of
incomplete dominance
The reason why some individuals who inherit polydactyly (having an extra digit on the hand or feet) do not express the trait is due to
incomplete penetrance
Which description below explains epistatic inheritance?
inheritance in which one gene can override another
DNA is directly inherited from an organism's parents, via their gametes, which are produced by the process of ________ Thus, if a person has phenylketonuria, they have inherited genetic information that has lead to the production of a dysfunctional protein, specifically a(n) _________ that normally breaks down phenylalanine.
meiosis, enzyme
A certain gene has 5 possible alleles throughout a population. The trait controlled by this gene has/is
multiple alleles
When a trait exists in several allelic forms within a population, the trait is referred to as being controlled by
multiple alleles
Offspring inherit _________________; if one or both parents passes on a gene with DNA that does not code for functional proteins, disorders like phenylketonuria can result.
one copy of each gene from both parents
The "P" in P generation refers to
parental
A single, simple, recessively inherited mutation inactivates the enzyme that converts phenylalanine to tyrosine. Homozygous recessive individuals possess an excessive amount of phenylalanine and a deficiency of tyrosine. Additionally, these individuals may be mentally deficient, have abnormally light hair and abnormally light skin color. This disorder is an example of
pleiotropy
The condition in which a single mutant gene affects more than one distinct characteristic of an individual is called _______
pleiotropy
A condition in which two or more sets of alleles control genetic patterns is controlled by _____ inheritance.
polygenic
The human population exhibits a continuous phenotypic variation in height and weight because these traits follow
polygenic inheritance
When an individual of African descent marries and has children with an individual of European descent, their children often have a mid-shade of skin color, but they could also have a light shade or a dark shade. This can best be described as
polygenic inheritance
What is the definition of wild-type?
the most common phenotype observed in a natural population for a given characteristic
Recessive alleles seem to vanish in some generations and reappear in later generations because
they are masked by a dominant allele
When Mendel crossed short (tt) pea plants with short (tt) pea plants the offspring
were all short
The most common phenotype or allele for a gene in a population is referred to as
wild type
