Hi I am studying for a biology exam and I have some questions that are on a revi
ID: 7652 • Letter: H
Question
Hi I am studying for a biology exam and I have some questions that are on a review sheet that i am unsure about
1. In Tomatoes, the allele for red fruit is dominant over the allele for yellow fruit. If a plant that is homozygous for red fruit is crossed with a plant with yellow fruit –
a) what is/are the genotype(s) and the phenotype(s) of the fruit produced in the F1 generation?
b) what is/are the genotype(s) and the phenotype(s) of the fruit produced in the F2 generation?
c) what is the phenotypic ratio of the F2 fruit?
2. A plant with red flowers is crossed with a plant with white flowers. All the F1 plants produced red flowers. When the F1 plants are allowed to self-pollinate, they produce 623 plants with red flowers and 198 plants with white flowers. What are the genotypes of the P and F1 generations?
3. In Tomatoes, the allele for red fruit is dominant over the allele for yellow fruit. The allele for tall plants is dominant of the allele for short plants. Find the genotypes and phenotypes of the F1 and F2 generations and the phenotypic ratio of a cross between a homozygous dominant in both genes and a homozygous recessive in both genes. The homozygous individuals are the Parental generation.
4. In cocker spaniels, solid coat color is dominant over spotted coat. A veterinarian has a spaniel with a solid coat. How can she unequivocally determine the genotype of this animal for coat color from a single breeding?
Explanation / Answer
Gametes can be produced by organisms with the following genotypes are
RrGg - RG, Rg, rG, rg
rrGG - rG
RrGG - RG, rG
rrgg - rg
2).progeny expected in the following crosses are-
RrGg x RrGG
RG Rg rg rG
RG RRGG RRGg RrGg RrGG
Rg RRGg RRgg Rrgg RrGg
Rrgg x rrGG
Rg rg
rG RrGg rrGg
RrGG x Rrgg
RG rG
Rg RRGg RrGg
rg RrGg rrGg
RrGg x rrgg
RG Rg rg rG
rg RrGg Rrgg rrgg rrGg
3). allele for red fruit is R and for yellow is y.
cross between homozygous for red fruit and with a plant with yellow fruit gives the following progeny-
RR * yy
F1 - Ry - red fruit.
cross between F1 progeny gives the following-
Ry * Ry
F2 -
RR - red fruit
Ry- red fruit
Ry- red fruit
yy- yellow fruit.
a) genotype(s) and the phenotype(s) of the fruit produced in the F1 generation are Ry - red fruit
b) genotype(s) and the phenotype(s) of the fruit produced in the F2 generation- RR, Ry- red fruit and yy-yellow fruit.
c) phenotypic ratio of the F2 fruit is 3:1.
4). plant with red flowers is crossed with a plant with white flowers. All the F1 plants produced red flowers
F2 produce 623 plants with red flowers and 198 plants with white flowers.
parents - RR * ww
- Rw - red flowers.
cross between F1 progeny gives the following-
F1 - Rw * Rw
RR - red flower
Rw- red flower
Rw- red flower
ww- white flower.
623 and 198 are 3:1 ratio.