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Genetics Unit Biology II
Genetics
Notes Day 1
Warm up-What is the definition of genetics?
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Gregor Mendel (1860’s)
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Father of genetics.
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Studied pea plants.
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Performed experiments with pea plants.
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Used a __________________________ approach.
Why do pea plants work well for genetic study?
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___________ __________ - have male and female structures
- Can do self-fertilization
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____________________________________________________________
____________________________________________________________
Can cross-pollinate them
- Cross Pollinate = Manually take __________ from one pea plant and place
it on the ____________ of another pea plant.
Mendel’s Experiment
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Step 1 - ______________________________________________________
– Let the plants self fertilize repeatedly.
• Purple plants self-fertilized to make ONLY __________ offspring
• White plants self-fertilized to make ONLY __________ offspring
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Collected seeds from these plants.
These were the PARENTAL GENERATION ( __ __________________)
Genetics Unit Biology II
• Step 2 - ______________________________________________________
– Purple flowers cross pollinated with white flowers.
– Collected and grew the seeds from these plants
– Called this the First Filial Generation (____)
– ___________________________________
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Step 3 - ______________________________________________________
– He collected and grew these seeds
– Called this the ____ generation.
– Purple flowers grew AND White flowers grew
– _______________________________________
Mendel studied many traits of Pea Plants
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____________________________________________________________.
Seed color (yellow or green).
____________________________________________________________.
Pod color (green or yellow).
He always found that there was a 3:1 ratio!
Terms to Know
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________________: the alternative traits that are passed down
-Example: mom passed down the allele for blue eyes while dad
passed the allele for brown.
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________________: The expressed form of the trait.
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________________: The trait that is not expressed when the dominant
allele is present.
EXAMPLE:
Allele for brown (dom) eyes from dad
Allele for blue (rec) eyes from mom
Child will have brown eyes.
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Genetics Unit Biology II
• _________________: The two alleles that are passed down are the same.
-Example: Both pea plant parents passed down the allele for purple
flowers.
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_________________: The two alleles that are passed down are different.
-Example: One pea plant parent passed down the allele for white flowers
and one passed down the allele for purple flowers
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_____________________: The set of alleles that an organism has.
-PP (homozygous dominant)
-Pp (heterozygous)
-pp (homozygous recessive)
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_____________________: The physical appearance.
-purple (homozygous dominant)
-purple (heterozygous)
-white (homozygous recessive)
List 10 Phenotypes
List 10 Genotypes
1._______________
2._______________
3._______________
4._______________
5._______________
6._______________
7._______________
8._______________
9._______________
10.______________
1._______________
2._______________
3._______________
4._______________
5._______________
6._______________
7._______________
8._______________
9._______________
10.______________
Genetics Unit Biology II
Genetics
Notes Day 2
Warm Up – What is the difference between a genotype and phenotype? Provide an
example of each.
Genotype:
Phenotype:
Punnett Squares
Punnett Square = ____________________________________________________
__________________________________________________________________
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__________________________________________________________
__________________ & _______________ alleles are represented by
_____________.
A _______________ letter is used for dominant alleles.
A __________ _____ letter is used for recessive alleles.
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EXAMPLE (Tall or short)
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T = dominant allele
t = recessive allele
Homozygous dominant
Genotype = _____
Phenotype = __________
Heterozygous
Genotype = _____
Phenotype = __________
Homozygous recessive
Genotype = _____
Phenotype = __________
CREATING A PUNNETT SQUARE
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The letters representing the alleles from one parent are placed along the top of
the square.
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The letters representing the two alleles from the second parent are placed along
the side of the square.
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Genetics Unit Biology II
T t x T t
The genotype (____________ ____________) can be used to predict the phenotype
(___________ _____________) of the offspring.
Probability: ________________________________________________________
Punnett Squares:
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Help you keep track of traits.
Predict genotype and phenotype.
Calculate probability.
BB x bb
Genotypes:
Phenotypes:
BB x Bb
Genotypes:
Phenotypes:
Genetics Unit Biology II
___ Bb
A. Mendel
___ bb
B. Monohybrid cross
___ BB
C. Dihybrid cross
___ father of genetics
D. Phenotype
___ Blood type AB
E. Genotype
___ letters like (Ff)
F. Heterozygous
___ traits like (freckles)
G. Dominant
___ 4 square Punnett square
H. Recessive
___ 16 square Punnett square
I. Cross pollination
___ pollen from one plant transferred to another
J. Co-dominant
Fun facts: Genetics
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Unless you are an identical twin, your DNA is unique.
Fingerprints are unique to each person, even identical
twins.
Your gender and physical characteristics are determined
by your DNA.
Genes exist in pairs; one half comes from a person's
mother and the other half from the individual's father.
Humans have at least 30,000 genes.
Goldfish have more genes than humans do