Module 8 (vocabulary is on Biology ipad app) Flashcards
Three pea plants have the following alleles for yellow (“Y”) and green (“y”) peas. What is the genotype and phenotype of each? Note whether they are homozygous or heterozygous.
a. YY b. Yy c. yy
a. “YY,” resulting in a phenotype of yellow peas
b. “Yy,” resulting in a phenotype of yellow peas
c. “yy,” resulting in a phenotype of green peas
What process causes gametes to have only one allele, since other human cells have two of each alele?
Meiosis separates the two alleles.
A pea plant which is homozygous in the dominant, axial flower allele (“A”) is crossed with a pea plant that is heterozygous in that alele. What are the possible genotypes and phenotypes, along with their percentage chances, for the offspring?
50% of the off offspring have “AA” genotype and 50% have the “Aa” genotype; 100% have the axial flower phenotype
A woman is heterozygous in the ability to roll her tongue when extended. If she marries a man who cannot roll his tongue, what percentage of their children will be able to roll their tongues? Remember, the allele for being able to roll your tongue is dominant.
50% of the children will be able to roll their tongues
See page 259, #6
the genotype is “Bb”
See page 260 #7
no wings (“N”) is the dominant allele; 1 and 2 must have the “Nn” genotype; 3 and 4 must also have the “Nn” genotype
Give the possible phenotypes and the percentage chance for each in the dihybrid cross between a pea plant that is homozygous in producing smooth, yellow peas and a pea plant that produces wrinkled, green peas. The smooth and yellow alleles are dominant.
100% of the offspring have the “SsYy” genotype and the smooth, yellow phenotype
Give the possible phenotypes and the percentage chance for each in the dihybrid cross between a pea plant that is heterozygous in producing smooth, yellow peas and another with the same genotype.
smooth, yellow peas 9 of 16 or 56.25%
smooth, green peas 3 of 16 or 18.75%
wrinkled, yellow peas 3 of 16 or 18.75%
wrinkled, green peas 1 of 16 or 6.25%
If fruit flies, the color of the eye is a genetic trait that is sex-linked. What is the percentage of males that will have white eyes when a heterozygous, red-eyed female is crossed with a white-eyed male? What is the percentage of females that will have white eyes from the same cross?
50% of the females (remember, only XX’s are females) will be white-eyed and 50% of the males (only XY’s are males) will be white-eyed
In the case of the fruit fly eye color again, what must be the genotype of a male fly if, when crossed with a heterozygous female, there is no possibility of having a female with white eyes?
XRY
If a gamete has two alleles for the same genetic trait, what type of genetic disorder will result in a zygote formed with this gamete?
change in chromosome number
A person carries a genetic disorder but does not have the disorder. How is that possible?
genetic disorder must be recessive
Do sex-linked genetic disorders affect men and women the same? If not, which sex is affected more and why?
sex-linked disorders affect men more frequently than women because men have only one allele in sex-linked traits
Two individuals have the exact same genotype for a certain trait, but they are not identical when it comes to that trait. How is this possible?
While the genetics are the same, the environmental and spiritual factors were probably different.
A woman with type O blood marries a man with type AB blood. What blood types are possible for their children? What is the percentage chance for each blood type?
A (50%) and B (50%)
