Transcript Back - wallrichscience

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• If a cell starts out with
46 chromosomes,
how many will it end
up with at the end of
meiosis?
• 23
Back
• In meiosis, what type
of cells are produced?
• Sex cells or gamates
Back
What is an allele?
• Different forms of a
gene.
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• How does an allele
relate to a gentoype?
• 2 alleles make up a
genotype for a trait.
Back
• Name 3 ways mitosis
and meiosis are
different.
• Mitosis- identical cells,
meiosis = gamates
• Mitosis 2 cells created
meiosis 4
• Meiosis haploid;
meiosis diploid
Back
• Organisms that have
2 identical alleles for a
particular trait.
• Homozygous
• Or purebred
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• What is the purpose of
genetic screening?
• To see if you have
mutations (faulty
genes)
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• What is a phenotype
and genotype of an
individual?
• Phenotype – Physical
traits
• Genotype – Genes
inside
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• If a pea plant has tt for
height, what can you
say about its parents
• They each have the t
allele….don’t know
the other allele
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• Describe how a trait is
expressed from the
DNA.
• By making a Protein
that does a function
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• In humans, people
can either roll their
tongues or not. How
many alleles are there
for tongue rolling?
• 2
• R=rollers
• r = non rollers
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• Each individual
inherits ____allele
from Mom and one
from Dad.
• one
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• Two mice with black
fur were crossed and
produced offspring
with black fur and
offspring with white
fur. If black is
dominate over white,
what would represent
the most probable
genotypes of the
parental mice?
• Bb x Bb Heterozygous
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• In humans, dimples is
completely dominant
to no dimples. Two
parents that are both
heterozygous for
dimples are expecting
a child. What are the
chances that the child
will have dimples?
Complete a punnett
square.
• 75%
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• What is best way to
determine the
phenotype of a guinea
pig is to?
• Observe it
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• A cross of a red flower
with a white flower
produces pink flowers.
This is a type of
inheritance called
• In-complete
Dominance
Back
• If a trait is
codominant, what will
the offspring look like?
• Give an example to
support your answer
• They will have both of
the parents traits
• Red + white = red and
white
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• Situations where an
allele is NOT
completely dominant
over the other allele is
called______
• Incomplete
dominance
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• A woman carrying the
gene for hemophilia
marries a man who is
a hemophiliac. What
percentage of their
children can be
expected to have
hemophilia? Complete
Punnett Square
• 50%
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• Co-Dominance. A
black chicken and a
white chicken produce
a checked chicken. If
two checkered
chicken are crossed
what is the phenotypic
and genotypic ratios?
Show your work using
a Punnett square.
• Pheno – B:C:W
0:2:2
• Geno - BB:BW:WW
0: 2 : 2
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• What shapes
represent males and
females in a
pedigree?
• Square – Males
• Circles - Females
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• True or False: Genetic
counselors often help
people with a family
history of genetic
disorders. Give an
example.
• True
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• Name three purposes
of a pedigree.
• To understand how
traits are passed on
• Identify disorders in
future generations
• Represent genetic
relationships between
family members
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• Identify the type of
pedigree below:
• Sex-Linked
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• Identify the type of
pedigree below & give
the genotype of
individual I-1.
• Autosomal Dominant
• Heterozygous
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• What are the genotypes of the following
individuals?