Review Sheet for Genetics Test
A Punnett square shows the possible combinations of Genes.
A pea plant with two tall genes is said to be pure tall.
Characteristics that an organism has are its traits.
An organism with two like genes for a trait is said to be pure.
When one parent is pure dominant and the other parent is pure recessive, and offspring will be hybrid
dominant.
A gene that always shows up in the offspring is a dominant gene.
The passing of traits from parent to offspring is called heredity.
Inherited traits are controlled by genes.
Most plants and animals reproduce sexually.
Traits are an organism’s physical characteristics.
Budding in a hydra is an example of asexual reproduction.
An offspring that is the result of asexual reproduction inherited genes from a single parent such as a
hydra.
Alleles are different forms of a gene.
Why does a person who inherits an allele for curly hair and an allele for straight hair have curly hair? The
allele for curly hair is dominant.
Chromosomes are made partly of long-chained molecules called DNA.
A(n) gene is a segment of a DNA molecule containing information that governs a specific trait.
Sexual reproduction results in the offspring that are not exactly like either parent.
A(n) dominant allele is one whose traits always shows up in an organism that has inherited that allele.
Because the allele for a smooth chin is recessive, a person must inherit two such alleles in order to have
a smooth chin.
A recessive allele of a gene is hidden whenever the dominant allele of the gene is present.
Make a Punnett Square for the following:
a. Dominant Short hair bear (homozygous) mates with a recessive long haired bear (homozygous).
List the offspring’s genotypes and phenotypes:
Genotype: 100% Ss
Phenotype: short hair
s
s
S
Ss
Ss
S
Ss
Ss
b. Dominant Green flower (hybrid) crossed with a recessive white flower. List the offspring’s
genotypes and phenotypes:
Genotype: 50% Gg 50% gg
Phenotype: 50% green 50% white
g
g
G
Gg
Gg
g
gg
gg
c. Homozygous blood type A with a heterozygous blood type AB. List the offspring’s genotypes
and phenotypes:
Genotype: 50% AA 50% AB
Phenotype: 50% Blood Type A 50% Blood Type AB
A
B
A
AA
AB
A
AA
AB
d. Heterozygous Brown hair crossed with a homozygous dominant Brown. List the offspring’s
genotypes and phenotypes:
Genotype: 50% BB 50% Bb
Phenotype: 100% Brown hair
B
B
B
BB
BB
b
Bb
Bb