Jeopardy

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Jeopardy
Mendel, Genotypes and Phenotypes
Punnett Squares
Meiosis
Non-Mendelian Inheritance
Pedigrees
Q 100
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Q 200
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Q 300
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Q 400
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Q 500
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Q 500
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Q 500
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100 Question Meiosis
What is crossing over? During which phase of
meiosis does crossing over take place?
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100 Answer Meiosis
Crossing over is when homologous chromosomes swap
segments of DNA. Crossing over occurs during
prophase I (or prometaphase I) of meiosis.
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200 Question Meiosis

• A crayfish cell has 200 total or 100 pairs of
  chromosomes. Following mitosis, the daughter
  cells would each have a total of ______
  chromosomes. After meiosis, the four daughter
  cells would have _____ chromosomes.
• 200, 200
• 100, 100
• 100, 200
• 200, 100
• 46, 23

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200 Answer Meiosis
d. 200, 100
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300 Question Meiosis

• Compare and contrast the daughter cells produced
  by meiosis to the parent cell in terms of
• Number of cells.
• Chromosome number.
• Composition of chromosomes.
• Purpose of cells.

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300 Answer Meiosis

• Parent cell
• 1 cell
• 2n (diploid), in humans 46.
• Chromosomes have not gone through crossing over,
  so maternal and paternal chromosomes are
  separate.
• Cells generate sex cells, gametes, sperm or
  eggs, etc.
• Daughter cells
• 4 cells
• 1n (haploid), in humans 23.
• Chromosomes have gone through crossing over so
  maternal and paternal chromosomes have a mix of
  DNA also, chromosomes have been assorted
  independently.
• Cells are sex cells, gametes, sperm or eggs, etc.

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400 Question Meiosis
How are the processes of meiosis and
fertilization shown in Punnett squares? How do
Punnett squares illustrate Mendels laws of
independent assortment and segregation?
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400 Answer Meiosis
Punnett squares show meiosis through the
separation of alleles (Bb being separated into B
and bs, for instance) which is Mendels law of
segregation and in alleles assorting
independently of one another (BbTt forming four
kinds of gametes) which is Mendels law of
independent assortment.
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500 Question Meiosis
Disorders like Down Syndrome, Trisomy 13
Syndrome, etc. result when the zygote ends up
with aneuploidy an abnormal number of
chromosomes. Plants sometimes end up polyploid
having a 3n or 4n chromosome number, which can
found a new species of plant. Given what you
know about meiosis, propose how both aneuploidy
and polyploidy result.
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500 Answer Meiosis
Anueploidy and polyploidy both result from
non-disjunction, when chromosomes fail to divide
properly in meiosis. Aneuploidy generally results
when one set of homologous chromosomes (for
instance, chromosome 21 in the case of Down
syndrome) fails to separate in anaphase I of
meiosis. The resulting gametes have an abnormal
number (22 or 24) of chromosomes. In plants, an
entire set or sets of homologous chromosomes fail
to separate, leading to gametes that are 2n or
3n, resulting in 3n or 4n offspring. (Or two
plants can do this, each with 2n gametes, etc.)
This results in plants having high chromosome
numbers and sometimes the formation of a new
species.
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100 Question Mendel, Genotypes, and Phenotypes
What is the difference between a genotype and a
phenotype?
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100 Answer Mendel, Genotypes, and Phenotypes
Genotypes refer to an organisms internal
genetic code phenotypes refer to an organisms
external appearance or behavior.
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200 Question Mendel, Genotypes, and Phenotypes
Use the following traits to complete questions on
genotypes, phenotypes and Punnett squares. Two
Antennae (A) vs. One Antennae (a) Pointy Ears (I)
vs. Round Ears (i) A male has the genotype AA
and is heterozygous for ear shape. His wife is
heterozygous for antennae and ii for ear shape.
What will their phenotypes be?
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200 Answer Mendel, Genotypes, and Phenotypes
Him Two antennae, pointy ears. Her Two
antennae, round ears.
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300 Question Mendel, Genotypes, and Phenotypes

• During Mendels experiments, he crossed a pea
  plant with smooth peas with a pea plant with
  wrinkled peas. All the plants in the F1
  generation had smooth peas. From this
  information, you can conclude
• a. The smooth allele is dominant to the wrinkled
  allele because the smooth allele hid the presence
  of the wrinkled allele.
• b. The smooth and wrinkled alleles are codominant
  to each other.
• c. The smooth and wrinkled alleles are
  incompletely dominant to each other.
• d. The wrinkled allele is dominant to the smooth
  allele because the wrinkled allele was hidden by
  the smooth allele.

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300 Answer Mendel, Genotypes, and Phenotypes
a. The smooth allele is dominant to the wrinkled
allele because the smooth allele hid the presence
of the wrinkled allele.
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400 Question Mendel, Genotypes, and Phenotypes
An experimenter wants to determine if a plant
with purple flowers is homozygous dominant or
heterozygous for the trait. Purple flowers are
dominant to white flowers. Design an experiment
that would determine which genotype the plant
has.
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400 Answer Mendel, Genotypes, and Phenotypes
Cross the plant with purple flowers with a plant
with white flowers, which are always homozygous
recessive. If half the offspring are white, the
plant is heterozygous. If all the offspring are
purple, then the plant is homozygous dominant.
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500 Question Mendel, Genotypes, and Phenotypes
Both pink and blue hydrangeas have the same
genotype for flower color. Explain how the same
genotype can produce two different flower colors.
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500 Answer Mendel, Genotypes, and Phenotypes
The hydrangeas phenotypes are, in part,
determined by the soil in which they are planted.
Pink flowers result from acidic soils, blue
flowers from basic soils and intermediate
(purple) flowers from more neutral soils. Just
as environment (sunlight, fake tanning) can
influence phenotype in humans, it can also
influence phenotype in plants.
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100 Question Punnett Squares
Perform the following cross Ss x Ss. (S short
fur, s long fur.) What are the genotypes and
phenotypes of the offspring?
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100 Answer Punnett Squares
S s
SS Ss
Ss ss
S s
Genotypes 25 percent homozygous dominant 50
percent heterozygous 25 percent homozygous
dominant Phenotype 75 percent short fur 25
percent long fur
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200 Question Punnett Squares
Hair color in humans is NOT sex-linked. Brown
hair (B) is dominant to blond hair (b). A
blond-haired woman has children with a male
heterozygous for hair color. What percentage of
their offspring are likely to have blond
hair? a. 0 percent b. 25 percent c. 50
percent d. 75 percent e. 100 percent
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200 Answer Punnett Squares
c. 50 percent
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300 Question Punnett Squares
Two parents heterozygous for two traits mate and
have children. How many of their children are
likely to be homozygous dominant for both traits?
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300 Answer Punnett Squares
One out of sixteen.
AB Ab aB ab
AABB AABb AaBB AaBb
AABb AAbb AaBb Aabb
AaBB AaBb aaBB aaBb
AaBb Aabb aaBb aabb
AB Ab aB ab
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400 Question Punnett Squares
An individual homozygous dominant for two traits
(unattached earlobes and brown eyes) has children
with an individual homozygous recessive for two
traits (attached earlobes and blue eyes). WITHOUT
performing a Punnett square, predict what the
genotypes and phenotypes of the offspring will be.
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400 Answer Punnett Squares
All offspring will be heterozygous for both
traits and have unattached earlobes and brown
eyes.
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500 Question Punnett Squares
A scientist crosses two plants heterozygous for
two traits and gets the following phenotypic
ratios. Explain how these numbers could be so
different from the expected phenotypic ratios.
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500 Answer Punnett Squares
These genes are located on the same chromosome,
therefore they do not assort independently of one
another. These are known as linked genes. When
phenotypic ratios are significantly different
from what we expect with independent assortment,
we can conclude something else such as gene
linkage may be at work. Depending on how
frequently genes assort independently from one
another, we can establish how far away from each
other they are on a chromosome.
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100 Question Pedigrees
Two people in a pedigree are linked like this
What is the relationship between them?
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100 Answer Pedigrees
They are married. You can tell by the line
connecting them.
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200 Question Pedigrees
In the above pedigree, people with
brachodactylia, a dominant trait, are shaded in
while people with a recessive trait are left
blank. Use a B for brachodactylia and a b for
normal fingers. What are the genotypes of II-8
and II-2? How do you know?
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200 Answer Pedigrees
II-8 - bb, because the person is homozygous
recessive since his square is unshaded II-2 - Bb.
The person must be heterozygous, since her
parents are Bb and bb. To be shaded, she must
have the dominant trait and cannot be BB.
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300 Question Pedigrees
The following pedigree shows the inheritance of a
recssive trait in a family. Those with the
recessive trait are shaded in red. What are the
genotypes of I-1 and II-2? How do you know?
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300 Answer Pedigrees
I-1 is homozygous recessive because he shows the
recessive trait. II-2 is heterozygous because
half her children are homozygous recessive and
half are heterozygous.
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400 Question Pedigrees
For the above pedigree, people with a trait have
been shaded in. Is this trait dominant or
recessive? HOW DO YOU KNOW?
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400 Answer Pedigrees
The trait is dominant. If its dominant, both
parents are heterozygous and the affected
offspring are either homozygous dominant or
heterozygous. If a trait is dominant, then
people with at least one allele for the trait
will show the trait in their phenotype. If the
trait is recessive, then those with the trait are
homozygous recessive and cannot have offspring
that have a dominant allele.
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500 Question Pedigrees
For the above pedigree, people with a specific
trait have been shaded in red. Note that only
males (squares) have the trait, while females may
be carriers, but do not have the trait. Propose a
possible system of inheritance for the trait that
explains these observations.
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500 Answer Pedigrees
The trait displayed is hemophilia, which is known
as a sex-linked trait. Sex-linked traits tend to
be shown more in males, since males have the
genotype XY. Because they only have one X
chromosome, a trait, even a recessive trait,
carried on that X will give them that phenotype.
(They are known as hemizygous since the X and Y
chromosomes are non-homologous.) Sex-linked
recessive traits are, as result, much more common
in males than in females, who have a second X
chromosome. This issue was compounded by the
cousin-marriages practiced by European royalty,
which means that a rare harmful allele became
more common when people who were closely related
married and had children.
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100 Question Non-Mendelian Inheritance
A red flower is crossed with a white flower. The
resulting offspring are all pink. What kind of
inheritance are these flowers showing?
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100 Answer Non-Mendelian Inheritance
This is incomplete dominance because the
offspring resemble and intermediate of the two
parents.
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200 Question Non-Mendelian Inheritance
A rabbit with black and white hair breeds with a
rabbit with black and white hair. 25 percent of
the resulting rabbits have black hair, 50 percent
have black and white hair, and 25 percent have
white hair. What kind of inheritance is displayed
here? How do you know?
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200 Answer Non-Mendelian Inheritance
These rabbits are displaying codominant
inheritance. We know because the rabbits can
display two dominant traits (black and white fur)
simultaneously.
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300 Question Non-Mendelian Inheritance
A woman with type A blood is married to a man
with type B blood. One of their children has type
A blood. The man suspects that the child is not
his (genetically). Can the child be his? SHOW
YOUR WORK!
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300 Answer Non-Mendelian Inheritance
IAIA or IAi x IBi.
IA IA IA i
IAIB IAIB
IAi IAi
IAIB IBi
IAi ii
IB i
IB i
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400 Question Non-Mendelian Inheritance
A person with type AB positive blood and a person
with type O negative are rushed to a hospital in
need of blood transfusions. Explain what kinds of
blood each person can receive and why.
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400 Answer Non-Mendelian Inheritance
The AB positive person can receive all blood
types A pos and neg, B pos and neg, O pos and
neg, and AB pos and neg. The type O negative
person can only receive type O negative
blood. People with Type AB blood, since they
have A and B sugars, can receive both A and B
blood. Everyone can receive O blood and their own
blood type. Rh positive people can receive
positive and negative blood. People with Type O
blood can receive Type O and Type O only. People
with negative blood can negative blood and only
negative blood.
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500 Question Non-Mendelian Inheritance
People with red hair and pale skin often
experience more dental pain than people of
different hair colors and skin tones. Explain
what could make this correlation possible, in
terms of non-Mendelian genetics.
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500 Answer Non-Mendelian Inheritance
Sometimes single genes can have multiple effects.
A mutation in the MCR1 gene can lead to lack of
brown pigmentation (red hair comes from the red
pigments showing through). A mutation in the same
gene can increase likelihood of experiencing
dental pain. This kind of inheritance one gene
with many effects is called pleiotropy.