Download 3.2 Probability Student pages

Lesson Review Questions
On separate paper.
Recall
1. Write a short paragraph in which you correctly use the concepts chromosome,
gene, allele, locus, and trait.
Apply Concepts
2. Use a Punnett square to determine the possible offspring genotypes of parents
with the genotypes Bb and bb.
Assume that B is the dominant allele for violet flower color in peas and b is the
recessive allele for white flower color. What is the expected ratio of violet-flowered
to white-flowered offspring based on your Punnett square?
Think Critically
3. Compare and contrast genotype and phenotype.
Points to Consider
Mendel choose wisely when he decided to study garden peas. Today we know that
not all organisms follow the basic patterns that he observed.
4. Can you think of a trait that has more than two phenotypes?
Dragon Genetics
1. In dragons, the allele for fire breathing is dominant. Dragons can be fire
breathers, or non-fire breathers.
Show the genotypes and phenotypes of all possible dragons.
2.If a heterozygous fire-breathing dragon is crossed with one that does not
breathe fire, how many offspring will be fire breathers?
3.If two heterozygous dragons are crossed, how many offspring would you
expect to NOT be fire-breathers?
4.Also in dragons, wings are a dominant trait. If you crossed two wingless
dragons, how many of their offspring would you expect to have wings?
5.If a purebred winged dragon is crossed with a purebred wingless dragon, how
many of their offspring will be winged and what is their genotype?
6. A dragon with wings (Dd) is crossed with ones that does not have wings. What percentage
of their offspring will be wingless?
Student Notes 3.2 Answers
1. A gene is a section of DNA, with many bases that code for a protein. This results in a trait.
2. Traits are controlled by genes. Genes are found on chromosomes and have a genetic code for a
protein.
The position of the gene on the chromosome is called the locus.
3. Different versions of a gene for a given trait are called
alleles. See Diagram: purple flower and white flower.
These alleles are how variations of traits occur
within a species.
4. In sexually reproducing organisms, chromosomes
come in pairs. They will have the same gene located
Allele for
at the same loci. The alleles may be the same or they maybe
white color
different for that trait.
5. When gametes unite in fertilization, the zygote inherits 2 alleles for every gene.
a. One from the __mom
Locus for
Flower
color
Allele for
purple color
b. One from the __dad
These 2 alleles = the individuals genotype. If they are the same= homozygous
and if they are different = heterozygous for that gene.
Example Genotypes alleles B and b, with B dominant to b
Genotypes
BB (homozygote)
Bb (heterozygote)
bb (homozygote)
6. The expression of the genotype is called the phenotype. Phenotype refers to the individuals traits.
Example Phenotype with Alleles B and b, with B dominant to b
Phenotypes
BB= purple flowers
Bb=purple flowers
bb= white flowers
7. Different genotypes can produce the same phenotype. How?
a. One allele is DOMINANT (B) to the other allele which is RECESSIVE (b)
Dominant and recessive are terms from Mendel’s factors.
8. What happens when you cross Bb x Bb? Give the genotype ratios and phenotype ratios
Student Notes 3.2
1. A _______is a section of DNA, with many bases that code for a __________.This results in a
_________.
2. Traits are controlled by ___________. Genes are found on _____________and have a
__________code for a protein.
The position of the gene on the chromosome is called the _____________
Locus for
Flower
color
3. Different ________________ of a gene for a given trait are called
_______________. See Diagram: purple flower and white flower.
These alleles are how _________________of traits occur
within a species.
4. In ____________________reproducing organisms, chromosomes
come in pairs. They will have the same ___________located
Allele for
Allele for
purple color
at the same __________. The alleles may be the __________ or
white color
they may be ________________for that trait.
5. When the______________unite in fertilization, the _____________inherits 2 alleles for every gene.
a. One from the ________
b. One from the ________
These 2 _____________= the
individuals ______________.
If they are the same= ________________ and if they are different = _______________for that gene.
Example Genotypes for the alleles B and b, with B dominant to b
Genotypes
_______ (homozygote)
_______ (heterozygote)
_______ (homozygote)
6. The _______________of the genotype is called the _________________. Phenotype refers to the
individuals traits.
Example Phenotype for the alleles B and b, with B dominant to b
Phenotypes
BB=______________ flowers
Bb=______________ flowers
bb= ______________flowers
7. Different genotypes can produce the same ____________________. How?
One allele is __________________(B) to the other allele which is ____________________ (b)
Dominant and recessive are terms from Mendel’s factors.
8. What happens when you cross Bb x Bb? Give the genotype ratios and phenotype ratios