Meiosis
Genetic Diversity
Mendelian Genetics
Non-Mendelian Genetics
X2
100
The type of cell division that produces gametes with half the chromosome number.
meiosis
100
The random alignment of homologous chromosome pairs during metaphase I.
independent assortment
100
An allele that masks the expression of another allele.
What is a dominant allele?
100
A pattern of inheritance where the heterozygote shows an intermediate phenotype.
incomplete dominance
100
The formula used to calculate chi-square values.
What is Σ[(observed − expected)² / expected]?
200
The stage of meiosis I in which homologous chromosomes pair and crossing over occurs.
prophase 1
200
The exchange of genetic material between homologous chromosomes
What is crossing over?
200
The expected phenotypic ratio from a monohybrid cross of heterozygotes
3 dominant : 1 recessive
200
Human blood type inheritance is an example of this pattern involving three alleles.
multiple alleles and co-dominance
200
This value is determined by the number of phenotypic categories minus one.
degrees of freedom
300
The key difference between meiosis I and meiosis II is that this process occurs only in meiosis I.
separation of homologous chromosomes or crossing over
300
This structure physically holds homologous chromosomes together during crossing over.
chiasma / chiasmata
300
In mice, black fur (B) is dominant to brown fur (b), and short tail (T) is dominant to long tail (t). Two mice that are heterozygous for both traits are crossed.
Predict the phenotypic ratio of the offspring.
Calculate the probability that an offspring has brown fur and a short tail.
What is an explanation that a BbTt × BbTt cross produces a 9:3:3:1 phenotypic ratio, that the probability of brown fur and short tail is 3/16
300
When two genes are located close together on the same chromosome and do not assort independently.
genetic linkage
300
If the calculated chi-square value is less than the critical value, this conclusion is made.
fail to reject null
400
Failure of chromosomes or chromatids to separate properly during meiosis.
nondisjunction
400
DAILY DOUBLE: Explain why crossing over increases genetic variation more than independent assortment alone.
What is that crossing over creates new allele combinations within chromosomes, not just whole chromosomes?
400
A cross between an AABb individual and an Aabb indivual occur. What is the probability that an offspring is genotype Aabb?
25%
400
A recessive allele that causes color blindness is located on the X chromosome.
A woman with normal vision has a father who is color-blind. She has children with a man who has normal vision.
Determine the genotype of the woman and explain your reasoning.
Predict the probability that a son will be color-blind.
Predict the probability that a daughter will be color-blind.
She is a carrier, because the dad can only pass on the color blind gene to her but she is normal vision from her mom.
50% chance the son is colorblind, 0% chance the daughter is colorblind
400
In a pea plant cross, purple flowers are dominant to white flowers. Two heterozygotes are crossed, and the observed results are: 78 purple, 22 white.
Perform a chi-square test to determine whether the observed results differ significantly from the expected results. You must show all work.
X2 = .48
df = 1
Pvalue = 3.84
Fail to reject null, simple mendelian and normal.
500
A student claims that cells become haploid only after meiosis II because sister chromatids separate at that stage. Explain why this claim is incorrect by identifying when cells become haploid during meiosis and what specifically changes in chromosome number at that point.
cells become haploid after meiosis I, when homologous chromosomes separate, reducing the chromosome number from diploid (2n) to haploid (n), even though sister chromatids remain joined?
500
A diploid organism has a chromosome number of 2n = 10.
Calculate the number of genetically different gametes that can be produced by independent assortment alone.
Explain why this calculation assumes no crossing over.
What is an explanation that an organism with 2n = 10 has n = 5, producing 2⁵ = 32 possible gametes from independent assortment alone, and that crossing over would increase genetic variation beyond this value?
500
In corn plants, kernel color (Y = yellow, y = white), kernel shape (R = round, r = wrinkled), and plant height (T = tall, t = short) are controlled by three independently assorting genes. Two plants heterozygous for all three traits are crossed.
Calculate the total number of possible gametes produced by one parent.
Determine the probability that an offspring is homozygous recessive for all three traits.
Explain how the product rule of probability applies to this situation.
What is an explanation that each parent produces 2³ = 8 possible gametes, that the probability of yyrrtt offspring is (1/4)³ = 1/64, and that independent events allow probabilities to be multiplied?
500
A woman with type A blood has a father with type O blood. She has children with a man who has type B blood and is heterozygous.
Determine the genotype of each parent (the woman and man) and justify your answers.
Use a Punnett square to predict the possible blood types of their offspring.
Calculate the probability that a child will have type AB blood.
woman: IAi, man: IBi.
AB, A, B, O
25%
500
In corn plants, seed color (yellow dominant to green) and seed texture (smooth dominant to wrinkled) assort independently. Two plants heterozygous for both traits are crossed. Complete a chi square analysis and show all work
Yellow, smooth = 312
Yellow, wrinkled = 111
green, smooth = 101
green, wrinkled = 36
expected values = 315, 105, 105, 35
x2 = ~.52-.55
df = 3
pvalue =7.82
fail to reject null