Vocab
Vocab 2
Key Points
Alleles and Genotypes
Punnett Squares
100
The scientific study of heredity.
Genetics
100
An organism with two different alleles for a trait.
Hybrid
100
Who is considered the father of modern genetics?
A priest named Gregor Mendel.
100
The alleles for a hybrid tall pea plant are -
Tt
100
Punnett Square A shows a cross between two black guinea pigs.
What is the probability that an offspring will be black? White?
Black: 3:4 or 75%
White: 1:4 or 25%
200
Each different form of a gene.
Allele
200
An organism that has two different alleles for a trait
heterozygous
200
Which of these genotypes is heterozygous?
AA
Bb
Cd
ee
Bb
200
Assume that purple flower color (P) is dominant over white flower color (p), what color would you expect a heterozygous genotype to be? Explain.
Purple, because the genotype would be Pp, one dominant allele and one recessive allele. If a dominant allele is present, it will always show that phenotype.
200
If black is the dominant color and white is the recessive, what color are the hamster parents shown in Punnett Square B?
What color are the parents shown in Punnett Square B?
300
Physical characteristics of an organism.
Trait
300
an organism’s genetic makeup, or allele combinations
genotype
300
Which of these is a phenotype?
tall, homozygous, allele, genotype
tall
300
If tall pea plants (T) are dominant over short pea plants (t), what would you expect the genotype to be of a short pea plant. Explain.
tt - In order for the recessive trait to show, both alleles must be the recessive allele.
300
Black coloring is dominant and white is recessive. Which guinea pig parent(s) in Punnett Square B is homozygous?
Which is heterozygous? Explain how you know?
The female, white guinea pig is homozygous recessive (bb), and the male, black guinea pig is heterozygous (Bb). If the black guinea pig parent were homozygous (BB), then there would be no chance for the offspring to be white; they would all be heterozygous black.
400
An allele whose trait always shows up in an organism.
The dominant allele.
400
an organism’s physical appearance
phenotype
400
In a cross between individuals that are Aa × Aa, how many boxes of the Punnett square will show an offspring that is homozygous dominant?
1 - AA
400
If two heterozygous green pea plants were crossed/bred, what are the resulting phenotype probabilities. Name them all.
Green - 3:4 or 75%
recessive/yellow - 1:4 or 25%
400
In this Punnett Square, what words would you use to describe the male and female parents (P generation)?
Both parents are heterozygous dominant genotype, which means they both show the dominant phenotype. Because they both carry the recessive allele, their offspring will have a 1:4, or 25% chance of producing a homozygous recessive genotype (recessive phenotype).
500
An allele whose trait is hidden in the presence of a dominant allele.
A recessive allele.
500
an organism that has two identical alleles for a trait
homozygous
500
In a cross between individuals that are Aa × Aa, what are the chances of producing a homozygous recessive offspring?
25%
500
If you cross a green pea plant (dominant) with a yellow pea plant, all it's offspring are green. What is the genotype of the original green pea plant? How do you know?
The original green pea plant must be homozygous dominant (GG) in order for the offspring of a cross between it and a yellow pea plant to all be green. If the original green plant were heterozygous (Gg), then the resulting offspring would have a 25% chance of producing a yellow pea plant.
500
For the following, assume that green peas are the dominant phenotype.
Punnett Square:
Y y
Y YY Yy
y Yy yy
Yellow peas probability: 1:4 or 25%
Green Peas probability: 3:4 or 75%