Pre 9
What was the ratio that Mendel observed between dominant and recessive traits in the F2 offspring of a monohybrid cross?
3 dominant:1 recessive
A characteristic ______ segregation in the F2 generation is referred to as the Mendelian ratio for a monohybrid cross.
3:1
How many potential phenotypes can result from a dihybrid cross when the traits assort independently from one another?
4
In terms of probabilities, the cross of a tall yellow seeded pea plant (TTYy) with a tall green seeded pea plant (Ttyy) is equivalent to which two monohybrid crosses?
TT x Tt and Yy x yy
Select all that apply Choose statements that correctly refer to components of Mendel's five-element model (please note that the answers use the modern term gene instead of factor).
The presence of an allele doesn't ensure that it will be expressed. Alternative forms of genes are called alleles. Parents transmit genes to offspring. The two alleles remain discrete.
cross-fertilization
pollen collected from a white flower introduced into a purple flower with male parts removed
cross-fertilization.
pollen collected from a white flower introduced into a purple flower with male parts removed
reciprocal fertilization
pollen from a white-flowered plant is used to fertilize a purple-flowered plant, while pollen from a purple-flowered plant is used to fertilize a white-flowered plant
To calculate the probability that if a woman has four children, they will all be girls, you should use the
product rule
Which of the following is NOT a component of Mendel's five-element model (please note that the answers use the modern term gene instead of factor)?
the two alleles are usually the same
Which term is used to refer to plant varieties in which offspring produced from self-fertilization remain uniform from one generation to the next.
true-breeding
A pea plant with green seeds is allowed to self hybridize. All of the resulting offspring plants produce green seeds as well. That plant is therefore considered to be a
true-breeding plant
A hybridization experiment involves mating
two individuals with different characteristics to each other
The probability of genotypes in an independently assorted dihybrid cross is based on the probabilities of
two monohybrid crosses
Prior to the work of Mendel, inheritance was viewed as resulting from
blending of traits from an offspring's parents.
Which of the following plants was the main organism for Mendel's genetic experiments?
pea
In a homozygous recessive individual the probability of the dominant allele being present is
0
In a heterozygous individual, the probability of a recessive allele being present in a gamete is
0.5
Click and drag on elements in order Place the steps of the Punnett square approach in the correct order.
1. Place the different female gametes along the side of a square and the different female gametes along the top of a square.2. Fill in the possible genotypes of offspring by combining the alleles of the gametes in the empty boxes.3. Determine the relative proportions of genotypes and phenotypes in the offspring.`
Click and drag on elements in order Place the three stages of Mendel's experiments in the correct order from first (on top) to last.
1. allowing plants to self-cross to ensure they are true-breeding.2. reciprocal crosses between true-breeding varieties.3. allowing hybrid offspring to self-fertilize.
In the cross of Pp x Pp four outcomes are possible: PP, Pp, pP, and pp. The probability of being heterozygous is ________.
1/2
When performing a monohybrid cross, Mendel noticed that not all individuals in the F2 generation were true breeding. What proportion were not?
1/2 of the F2 individuals exhibiting the dominant form were not true breeding.
How many possible allele combinations (consider all possible combinations, even those that are identical) are produced in the offspring of heterozygous parents in a dihybrid cross?
16
One of the parents in a dihybrid cross has the genotype AABb. How many types of gametes can this parent produce?
2
This ratio is obtained in the F2 generation of a dihybrid cross when alleles assort independently from one another.
9:3:3:1
An individual with genotype Aa can produce which gamete(s)?
A and a
Select all that apply Assuming independent assortment, which of the following are examples of gametes produced by an AaBb individual?
AB ab
Which of the following is an example of a testcross?
AaBb x aabb
In pea plants, the allele T encodes for tall plants, while the allele t encodes for dwarf plants. If a true-breeding tall pea plant is crossed with a true-breeding dwarf pea plant what are the expected genotypes of the offspring?
All Tt
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.
Which of the following is NOT one of the three main stages that Mendel conducted his experiments in?
Back crosses between F1 and P individuals
The law of independent assortment states that in a dihybrid cross, the ____________ of each gene assort independently.
Blank 1: alleles
A(n) ________ cross follows the simultaneous inheritance of two different characters.
Blank 1: dihybrid, two-factor, or 2-factor
An individual's total set of alleles for a particular trait is called his/her
Blank 1: genotype
A 9:3:3:1 ratio is obtained in the F2 generation of a dihybrid cross when alleles assort _______ from one another.
Blank 1: independently, separately, distinctly, autonomously, or individually
The physical appearance or other observable characteristic of an individual is called his/her _________
Blank 1: phenotype
An example of __________a cross is using pollen from a green-seeded pea plant to fertilize a yellow-seeded pea plant and then using pollen from a yellow-seeded pea plant to fertilize a green-seeded pea plant.
Blank 1: reciprocal
One of the traits that Mendel studied in pea plant is plant height. Tall plants are dominant with respect to dwarf plants. If the gene for this trait is denoted by the letter "T", then the genotype of a dwarf pea plant is________
Blank 1: tt
reciprocal fertilization
Choice, pollen from a white-flowered plant is used to fertilize a purple-flowered plant, while pollen from a purple-flowered plant is used to fertilize a white-flowered plant pollen from a white-flowered plant is used to fertilize a purple-flowered plant, while pollen from a purple-flowered plant is used to fertilize a white-flowered plant
What type of cross follows the simultaneous inheritance of two different traits?
Dihybrid cross
In a monohybrid cross, when there are a pair of alternate forms of a trait, in which generation is one of the traits latent, or present but not expressed?
F1
In a typical monohybrid cross, all of the offspring in which generation will exhibit a single trait without blending?
F1
True or false: Mendel found that plants exhibiting the recessive trait were usually not true-breeding.
False
True or false: Mendel's observations did not support the independent assortment hypothesis.
False
What type of experiment involves mating two individuals with different characteristics to each other? One individual provides females gametes, while the other provides male gametes.
Hybridization
This law states that in a dihybrid cross, the segregation of different allele pairs is independent.
Law of independent assortment
Which of following crosses is crossing two variations of a single trait?
Monohybrid cross
Match the following rules to their descriptions.
Multiplication rule -> used for independent events Addition rule -> used for mutually exclusive events
A(n) _______ square can be used to predict the outcome of a simple genetic cross.
Punnett
Which of these is commonly used to predict the results of simple genetic crosses?
Punnett square
Select all that apply A parent with a genotype of RrYy can produce which of the following gametes?
RY Ry rY ry
Select all that apply Which of these are not reasons that Mendel chose to study the garden pea:
They were inexpensive to buy Long generation time
Which of the following is an example of a monohybrid cross?
White and purple flowers
Mendel's observations supported the independent __________ hypothesis.
assortment
By convention, the phenotypic ratio from a Punnett square is written as
dominant:recessive
Prior to the 20th century, the two main ideas that provided the basis for most thinking about heredity were
heredity occurs within species traits are transmitted directly from parents to offspring
Consider a testcross where the unknown parent is heterozygous. The offspring will be
heterozygotes and homozygotes
If the offspring from a testcross contain only heterozygotes, the genotype of the unknown parent must be
homozygous dominant
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
Match these genotypes with the correct genetic symbols.
homozygous dominantmatches<->TTheterozygousmatches<->Tthomozygous recessivematches<->tt
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
In order to determine the likelihood of having a flipped coin come up on heads three times in a row, you would use the
multiplication rule
In the monohybrid crosses performed by Mendel, the F1 plants always displayed ____.
one trait
self-fertilization
takes place within an individual flower if it is not disturbed
self-fertilization
takes place within an individual flower if it is not disturbed takes place within an individual flower if it is not disturbed
The cross of an individual who has a dominant phenotype with an individual who is homozygous recessive for that gene is known as a
testcross
In Mendel's experiments, he observed a 3:1 ratio between dominant and recessive traits in
the F2 generation of monohybrid crosses.
