Chapter 12 | GEN BIO 111
This is the idea that the two alleles of a gene separate during the formation of eggs and sperm so that every gamete receives only one allele.
Principle of Segregation
A(n) ________ square can be used to predict the outcome of a simple genetic cross.
Punnet
Which of these is commonly used to predict the results of simple genetic crosses?
Punnett square
Select the rule of probability that is applied to events with mutually exclusive outcomes.
Rule of addition
The gene that determines ABO blood types encodes an enzyme that adds which of the following molecules to proteins on the surface of the red blood cells.
Sugars
If a cross between heterozygotes for a single trait results in three separate phenotypes, which of the following types of inheritance is the likely reason?
Incomplete dominance
Segregation of alleles occurs during which of the following processes?
Meiosis
Which type of cellular division involves the pairing and subsequent segregation of homologous chromosomes?
Meiosis
When two consecutive events occur, each one with its own probability (that does not depend on the the probability of the other event), we say that the two events are ________.
independent
A 9:3:3:1 ratio is obtained in the F2 generation of a dihybrid cross when alleles assort ________ from one another.
independently
A cross in which only a single trait is considered is called a(n) ________ cross or single factor cross.
monohybrid
An experimental cross where only a single characteristic is considered (for example, flower color) is called...
monohybrid
The inheritance patterns of many traits are (more or less) complex than simple Mendelian patterns.
more
Events that can not occur at the same time are called...
mutually exclusive
If a true-breeding tall pea plant is crossed with a true-breeding dwarf pea plant and all of the offspring are tall plants, the trait "tall plant" is...
dominant over "dwarf plant"
Match these terms with their definitions: 1. Homozygous... 2. Heterozygous...
1. individual carries two identical alleles of a gene 2. individual carries two different alleles of a gene
Mendel called the trait that was expressed in the F1 offspring of a monohybrid cross ________.
dominant
Of the following alleles for blood type, indicate which two alleles are codominant to each other.
1. IB 2. IA
Which of the following are examples of environmental effects on phenotype?
1. The number of seeds eaten by a bird affects its weight. 2. The amount of sunlight experienced by a sunflower affects the number of seeds produced.
Choose statements that correctly refer to components of Mendel's five-element model...
1. The presence of an allele doesn't ensure that it will be expressed. 2. Parents transmit genes to offspring. 3. Alternative forms of genes are called alleles. 4. The two alleles remain discrete.
Match the following blood type genotypes with phenotypes: 1. IAi 2. IBIB 3. ii 4. IAIB
1. Type A 2. Type B 3. Type O 4. Type AB
A parent with a genotype of RrYy can produce which of the following gametes?
rY ry RY Ry
The probability of tossing a coin and having it land on heads is...
0.5
Pair each type of inheritance with the appropriate characteristics: 1. incomplete dominance... 2. codominance...
1. the heterozygote is an intermediate in appearance between the two homozygotes 2. the heterozygote shows some aspect of both homozygotes
Examples of environmental influences on phenotype include...
1. the pattern of coat color in Siamese cats 2. the pattern of coat color in Himalayan rabbits
Prior to the 20th century, the two main ideas that provided the basis for most thinking about heredity were...
1. traits are transmitted directly from parents to offspring. 2. heredity occurs within species.
If a particular gene in a population has multiple alleles, how many alleles can a diploid individual inherit?
2
One of the parents in a dihybrid cross has the genotype AABb. How many types of gametes can this parent produce?
2
A Punnett square for a single trait should be a set up as a ________ square
2 x 2
This ratio is obtained in the F2 generation of a dihybrid cross when alleles assort independently from one another.
9:3:3:1
Which of the following statements describe pleiotropic alleles?
A pleiotropic allele can be dominant with respect to one trait and recessive with respect to another trait.
A woman who has type B blood and a man who has type A blood could have children with which of the following blood types?
A, B, AB, O
The trait for round (R) peas is dominant over the trait wrinkled (r) peas. What would happen if true-breeding round peas are crossed with true-breeding wrinkled peas?
All offspring will have round peas
In a typical monohybrid cross, all of the offspring in each generation will exhibit a single trait without blending?
F1
Which of the following alleles involved in human blood types are codominant?
IA and IB
Which of the following rules states the probability that two or more independent events will occur is equal to the product of their individual probabilities?
The rule of multiplication
When continuous traits are graphed with the phenotype on the X-axis and the number of individuals with that phenotype on the Y-axis, a ________-shaped curve results.
bell
A situation where a single individual expresses two different alleles is referred to as...
codominance
The expression of two different alleles simultaneously in the heterozygote is called ________.
codominance
The heterozygote shows some aspect of both homozygotes in which of the following?
codominance
When the expression of one gene obscures the effects of another gene, this is called...
epistasis
When the interaction of genes alters genetic ratios, this is called ________.
epistasis
The rule of addition is applied to events with mutually ________ outcomes.
exclusive
Mendel postulated that for a given character, every individual carries two genes that he referred to as ________.
factors
In his studies, Mendel referred to factors that are passed intact from one generation to the next. We now know that these factors are actually ________.
genes
Which of these are what Mendel referred to as "factors" that are passed intact from one generation to the next?
genes
Mendel postulated that every individual carries two ________, called alleles, for a given character.
genes or factors
An individual's total set of alleles for a particular trait is called his/her ________.
genotype
Consider a testcross where the unknown parent is heterozygous. The offspring will be ________.
heterozygotes and homozygotes
An individual who carries two different alleles of a gene is termed ________ with respect to that gene.
heterozygous
If the offspring from a testcross contain homozygotes and heterozygotes, the genotype of the unknown parent must be ________.
heterozygous
An individual with two identical alleles of a gene of a particular trait has a(n) ________ genotype with respect to that gene.
homozygous
Consider the "tall"/"short" traits of pea plants. A pea plant that carries two "tall" alleles is ________.
homozygous
The results of a testcross indicate that all of the offspring have a dominant phenotype. The genotype of the parent in question must be ________.
homozygous dominant
If a heterozygote displays a phenotype that is intermediate between the two homozygous individuals, then the trait must operate by...
incomplete dominance
The product rule states that the probability that two or more ________ events will occur is equal to the product of their individual probabilities.
independent
A Punnett square has rows and columns which represent gametes made by males and females. At the intersection of each row and column we combine the corresponding gametes to produce the genotype of a potential ________.
offspring or zygote
In the monohybrid cross performed by Mendel, the F1 plants always displayed ________
one trait
The physical appearance or other observable characteristic of an individual is called his/her ________.
phenotype
In snapdragons, alleles resulting in red pigment and white pigment exhibit incomplete dominance. If red snapdragons are crossed with pure white snapdragons the offspring of the F1 generation will be ________.
pink
An allele that has more than one effect on a phenotype is called ________.
pleiotropic
Continuous phenotypic variation results from...
polygenic inheritance and independent segregation of genes
The principle of ________ is that 2 alleles for a genes separate during gamete formation and are rejoined at random, one from each parent, during fertilization.
segregation
Individuals have two alleles for each gene and when gametes form by meiosis, the two alleles...
separate
In order for Mendel's simple ratios to hold true, the following assumption must be made:
that the traits are inherited independently
Mendel designated a dominant trait as the one...
that was expressed in the F1 generation.
A cross between heterozygotes for a single trait will lead to a genotypic ratio of 1:2:1. How many phenotypes will be observed if incomplete dominance is occurring?
three
The Blending Theory of Inheritance suggested that each parent contributes ________ that are blended together in their offspring.
traits
An individual can acquire only ________ allele(s) per trait, even if multiple alleles are present in the population.
two
Each parent carries ________ alleles of a gene that will segregate from each other during gamete formation.
two
Which of the following is NOT a component of Mendel's five-element model?
two alleles are usually the same