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Genetics Study Sheet- This study sheet must be complete before retaking the genetics test. The last day for retakes is March 18
Define Meiosis –
Define germ cellDefine haploidDefine sex-cellWhy must the sex cells be haploid prior to fertilization?
*Know genes are located on homologous chromosomes in corresponding pairs. For example, the allele for pink flowers is on one of
the chromosomes and the allele for white flowers is on the other chromosome. These two traits work together to code for a trait.
The alleles together are called a genotype. The expression of the genotype is the phenotype.
homologousallele genotypephenotypeHomozygous
Heterozygous
Dominant
Recessive
Codominant
Incomplete dominance
Label the following heterozygous (HE), homozygous dominant (HO-D) or homozygous recessive (HO-R)
ff
BB
Bb
cc
DD
Dd
For the homologous chromosomes
below show a heterozygous
combination for eye color genes,
brown is dominant to blue.
What is the genotype for the alleles shown?
What is the phenotype if pink is dominant
over white?
What is the genotype for the alleles
shown?
What is the phenotype?
What alleles can be present in the
sperm cells if this is the father?
or
gg
For the homologous chromosomes below
the individual has blue eyes, which is
recessive to brown eyes. Label the
alleles on the chromosomes
What is the genotype for the alleles
shown?
What is the phenotype?
What alleles can be present in egg cells if
this is the mother?
Or
From the above cross of the mother and the father draw and solve the Punnett square look like?
Genotypic ratios 50% Bb 50% bb
Phenotypic ratios 50% brown eyes, 50% blue eyes
For the homologous chromosomes
below show a heterozygous
combination for hair color where dark
hair is dominant over blonde.
For the homologous chromosomes below
the individual has blonde eyes, which is
recessive to dark hair. Label the alleles
on the chromosomes
Show the Punnett square the cross
between the couple and the possible
outcomes of their children.
Genotypic ratio
What is the genotype for the alleles
shown?
What is the phenotype?
What alleles can be present in the
sperm cells if this is the father?
or
What is the genotype for the alleles
shown?
What is the phenotype?
Phenotypic ratio
What alleles can be present in egg cells if
this is the mother?
Or
Karyotype below
To the left is a picture of an individual’s chromosomes
Approximately how many total genes are on these chromosomes?
Which ones are the autosomes?
Which ones are the sex chromosomes?
Is this a male or a female? How do you know?
Of each of these chromosomes how many of each number will be
inherited by this females offspring?
Will the egg cell created from this females germ cell be haploid or
diploid?
Why is it important for the cell to become haploid prior to
fertilization?
How many chromosomes should ideally be in the offspring?
Define nondisjunction-
Do the following crosses for autosomal traits. All of them show complete dominance inheritance pattern.
What chromosomes are the autosomal traits found on?
1.
Blue eye color is an autosomal recessive trait. Assume two individuals have blue eyes and have 8 children. What alleles
must be present on the parent’s homologous chromosomes?
And
.
What is the cross for these individuals?
X
Show the Punnett square for this cross.
Genotypic ratio
Phenotypic ratio
2.
In pea plants height is an autosomal dominant trait. If 2 heterozygous plants for height are crossed what is the
cross
X
Show the Punnett square
Genotypic ratio
Phenotypic ratio
3.
In pea plants round seeds are dominant to wrinkled seeds. If a plant that is homozygous recessive is crossed
with a heterozygous plant. The cross is:
X
Punnett square
Genotypic ratio
Phenotypic ratio
4.
How is it possible to have a black lamb from a white ewe and a white ram?
Cross must be
Punnett square
X
Genotypic ratio
Phenotypic ratio
5.
If the above white ewe and white ram, have a heterozygous genotype but do not produce any black lambs,
what’s up? Explain.
6.
A couple have three kids. Unfortunately, one of these children is born with cystic fibrosis. This disorder is
autosomal recessive. What is the genotype of both parents?
Or
Show the cross.
Codominance Crosses Co= both dominant alleles are expressed.
7.
8.
What does gene expression mean?
A black chicken (BB) is crossed with a white chicken (WW). What type of chickens can they produce?
Show the Punnett square
Genotypic ratio
Phenotypic ratio
9.
Two speckled chicken are crossed. Show the cross
X
Solve the Punnett square
Genotypic ratio
Phenotypic ratio
Incomplete dominance – neither allele expresses dominance over the other – BLENDING
10. A plant shows incomplete dominance for flower color. A red flower and a white flower often produce plants
with pink flowers. A red flower (RR) plant is crossed with a white flower cross (WW).
Show the cross
X
Punnett square
Genotypic ratio
Phenotypic ratio
11. Two pink flowers are crossed. Show the cross
Punnett square
X
Genotypic ratios
Phenotypic ratios
12. A red flower is crossed with a pink flower. Show the cross
Show the Punnett square
X
Genotypic ratio
Phenotypic ratio
U
Multiple alleles inheritance pattern is when 3 or more allele types are available, but only 2 are inherited. The ABO blood
type is an example of this type of inheritance
13. A woman with homozygous dominant type A blood (AA) and a husband with heterozygous type A blood (AO).
Show the Punnett square
Genotypic ratio
Phenotypic ratio
14. A woman with heterozygous B type and a man with type O blood (hint: O is recessive) have three children.
What are the possible blood types?
Punnett square
Genotypic ratio
Phenotypic ratio
Sex-linked traits. Sex-linked traits are inherited from alleles on the X or the Y chromosome. The traits studied in biology
include; Duchenne Muscular Dystrophy, colorblindness, and hemophilia. Memorize that these are sex-linked traits that
are found on the X chromosome. All conditions are recessive – requiring 2 alleles for inheritance in females and only
one in males because the chromosomes are not homologous.
Draw the alleles of a female without
the mutation- two normal (N) alleles
Draw a heterozygous combination of
alleles on the female- one normal
and one mutation
Label the X with a recessive allele
Does he inherit the disease?
Genotypes
Phenotype
What alleles can this female pass
along to her offspring?
Or
Genotype
Phenotype
What alleles can this female pass
along to her offspring?
Or
Genotype
Phenotype
What alleles can this pass along to
offspring?
*note only
one allele if it is on the X.
15. Show a cross between a normal female and a male with colorblindness.
Genotypic ratio of boys
Phenotypic ratio of boys
Genotypic ratio of girls
Phenotypic ratio of girls
16. Show the cross between a female that is a carrier for DMD and a man that has the normal allele for DMD.
Genotypic Ratio for boys
Phenotypic ratio for boys
Genotypic ratio for girls
Phenotypic ratio for girls
17. A female is a carrier for hemophilia with a father that has hemophilia (which is rare….especially these days when
we know this is a genetic disorder)
Genotypic Ratio of boys
Phenotypic ratio of boys
Genotypic ratio of girls
Phenotypic ratio of girls
18. A woman who is a carrier for hemophilia and a man that does not have this mutation have three children, 1 boy
has hemophilia, and the other two girls are being tested to determine if they are carriers.
Show the Punnett square to show the family these girls cannot have hemophilia
Explain to the parents why their girls will not inherit hemophilia, but may be carriers.
Define Gel Electrophoresis a. Write in the positive and negative charges on the gel electrophoresis below and use an arrow to show the
direction of movement. Since smaller molecules move further into the gel, the mutation (which is a deletion
in this case), the mutated DNA will move further into the gel. B. Assign the mutation with one color and the
normal with another. Key:
c. draw the band pattern for mom, dad
and boy 1.
Mom Genotype :
Mom Phenotype:
Dad genotype:
Dad phenotype
Boy Genotype:
Boy Phenotype
Girl 2 genotype
Girl 1 Genotype
Girl 2 phenotype
Girl 1 Phenotype
ABO blood type
Define antigen –
Define antibodyBlood type is an inherited trait and is expressed as self-markers (called antigens) on its surface. For example A+
blood would have antigens for A and Rh on its surface. The antibodies (immune system attackers) available
include A, B and Rh. The blood type will make opposite antibodies than its surface markers. If it made
antibodies for its antigens the antibodies would attack itself and the blood would clump. So for A+ blood it will
only make B antibodies. Thus, if B blood is given (and has antigens on its surface for B) the B antibodies would
attack and the blood would clump. Not a good situation.
Fill in the table below.
Blood Type
Genotypes
Antigens
Self-markers
Antibodies
Blood can safely get
Type A+
AB+
BAB+
ABO+
O*note – O- does not have any self-marker antigens and O+ would only have Rh self-marker antigens. Thus, Owould make all antibodies and O+ would make all except Rh.