Study cards for Chapter 14 "Mendelian Genetics" BIOL 189 CSN
List three reasons why Mendel chose to work with pea plants.
easy to grow
short growing time
each character had two traits
Describe the "blending" hypothesis.
If parents were of contrasting appearance, the offspring would have an intermediate appearance.
True or False: The "blending" hypothesis was proven correct in the 19th century.
False - Mendel disproved the blending hypothesis in the 19th century.
Describe what it means to be a "true-breeding" plant.
The plant is homozygous for it's specific characters and all self-pollinated offspring will have the same characters.
Gregor Mendel studied hereditary science during which decade of the 19th century?
The thought that red flowers crossed with white flowers would always yield pink flowers is an example of the:
Blending Concept of Inheritance
Mendel chose what type of plant to perform his hybridization experiments?
Inheritable features among individual are known as:
Variations of characters, such as flower color or eye color, are known as:
Why would you utilize true-breeding plants in the P generation?
to control which traits are being passed on
Cross polinating two true-breeding parent plants creates the _______ generation.
List the four primary tenets of Mendel's Model.
alternative versions of genes will cause variation in characters
individuals inherit two alleles for each character
if the alleles are different, one will override the other
during gamete formation, the two alleles will seperate and end up in different gametes
Alternate versions of genes that allow for variation in characters are known as:
True or False: The alleles you inherit can be identical or different.
Where do the two alleles for a specific gene come from?
one from each parent
The allele that overrides the recessive allele causing it to be masked is the:
The allele whose expression is only visible when the dominant allele is not present is the:
Explain the Law of Segregation.
During gamete formation, the two alleles for a specific gene seperate and end up in different gametes.
What is a Punnet Square used for?
to predict the alleles of an organisms offspring
If an organism is homozygous for a trait, it's alleles are:
True or False: An organism can be homozygous dominant or homozygous recessive.
If an organism has two alleles that are different, it is said to be:
heterozygous for the trait
The genotype expresses the ________ of the two alleles.
The phenotype is the physical expression of the:
Is blonde hair a genotype or phenotype?
Is homozygous recessive a genotype or phenotype?
In what circumstance would you do a "test cross?"
when you do not know the genotype of an organism
Assuming that red flowers are dominant to white flowers, if you cross an unknown red flowered plant with a true-breeding recessive plant (white flowers) and get all red plants, you know that the unknown parent plant was:
Assuming that yellow seeds are dominant to green seeds, if you cross an unknown yellow seeded plant to a true-breeding recessive (green seeded) plant, and you get half yellow seeds and half green seeds, you know that the unknown parent plant was:
Define a monohybrid.
organism that is heterozygous for a specific trait
An plant that is heterozygous (Tt) for a single trait is an example of a:
The two true-breeding plants that are crossed to begin a hybridization experiment are known as the ___ generation.
The result of crossing two heterozygous F1 plants is known as the ___ generation.
In a monohybrid cross all the plants in the F1 generation will be:
In a monohybrid cross the ratio of dominant to recessive phenotypes in the F2 generation will be:
3 to 1
True or False: The crossing of a true-breeding dominant plant (TT) with a heterozygous plant is an example of a monohybrid cross.
False - a monohybrid cross begins with a homozygous dominant parent and a homozygous recessive parent.
An organism that is heterozygous for two traits is known as a:
What is the difference between a dihybrid and a monohybrid?
a dihybrid is heterozygous for two traits while a monohybrid is heterozygous for only one
A cross between individuals who are heterozygous for a single trait is a:
A cross between individuals who are heterozygous for two traits is a:
True or False: In a dihybrid cross, the F1 generation will be heterozygous for both traits.
True or False: In a dihybrid cross the P generation will be heterozygous for both traits.
False - the P generation will be homozygous, either dominant or recessive, for both traits
For the P generation RRHH and rrhh, list the four gametes of the F1 generation.
In a dihybrid cross examining traits represented by G and Q, what will be the genotype of the F1 generation.
In a dihybrid cross considering traits R and T, what will be the P generation gametes?
RT and rt
Describe the Law of Independent Assortment.
each pair of alleles will separate independently
The fact that seed color alleles are independent of pod color alleles is an example of:
the Law of Independent Assortment
If you do not express a trait but are able to pass it on to your offspring you are known as a:
The practice of crossing plants with different genotypes resulting in daughter plants with new genotypic combinations is known as:
The probability scale ranges from ___ to ___.
0 to 1
A probility value of 1 is assigned to:
With two heterozygous parents, the probability of offspring that is homozygous dominant is:
1/4 or 25%
With two heterozygous parents, the probability of offspring that are heterozygous is:
1/2 or 50%
With two heterozygous parents, the probability of offspring that are homozygous recessive is:
1/4 or 25%
In a dihybrid cross, the probability of an F2 child expressing the dominant gene for both traits is:
9/16 or 56.3%
In a dihybrid cross, the probability of an F2 child expressing the dominant gene for trait 1 and the recessive gene for trait 2 is:
3/16 or 18.7%
In a dihybrid cross, the probability of an F2 child expressing the recessive gene for trait 1 and the dominant gene for trait 2 is:
3/16 or 18.7%
In a dihybrid cross, the probability of an F2 child expressing the recessive gene for both traits is:
1/16 or 6.2%
When the dominant allele completely masks the recessive allele you have this type of dominance.
True or False: There is no phenotypic difference between organisms that are homozygous dominant and heterozygous for a specific trait.
When neither allele dominates the other completely you have this type of dominance.
With incomplete dominance, when an organism is heterozygous, neither allele masks the other and you get an:
If two parents with alleles that exhibit incomplete dominance are crossed, what percentage of the F1 generation will display the intermediate effect.
100% - they will all be heterozygous
Consider two flowers, one red and one yellow, that are crossed. The F1 generation will have orange flowers due to incomplete dominance. What proportion of the F2 generation will have orange flowers?
How does codominance of alleles affect phenotypic expression?
both alleles are expressed in the phenotype
True or False: If two alleles are codominant, you will always see both contribute to the phenotypic expression.
Consider two organisms, one with white coloring and one with black coloring. If the alleles exhibit incomplete dominance, what can we expect of the color of their offspring?
it will be gray
Consider two organisms, one with white coloring and one with black coloring. If the alleles exhibit codominance, what can we expect of the color of their offspring?
it will be black and white striped
True or False: Each phenotype is always determined by one genotype.
False - each phenotype can be determined by multiple alleles.
If a person has type A blood, what are the possible genotypes?
IAIA and IAi
If a person has type B blood, what are the possible allele combinations?
IBIB and IBi
If a person has the blood genotype IAIB, what type blood do they have?
If a person has the alleles "ii," what type blood do they have?
Rh is determined by the presence, or absence, of:
the D antigen
A gene at a secondary location affecting the expression of a gene at the primary location is an example of:
True or False: In mice color is deposited on the fur only if they have a dominant allele for color deposition, regardless of the alleles for fur color.
When two or more genes have an added effect upon each other you have:
The example of polygenic inheritance discussed in class was:
True or False: Regarding skin color, as you decrease the number of dominant alleles, you decrease the amount of pigmentation.
What shape is used to denote males on a pedigree chart?
Circles represent which gender on a pedigree chart?
On a pedigree chart, if a person is affected by the trait, his/her shape will be:
True or False: The environment can affect phenotypic expression.
What environmental condition can affect the color of hydrangeas?
Hydrangeas that express blue petals must be growing in ______ soil.
What environmental process affects the color of jackrabbits?
changing of the seasons
True or False - In summer jackrabbits turn white.
False - the decrease in temperature of winter turns them white